Plant Sanitation and Safety

UNIT 18 ISSUES IN FOOD SAFETY

Structure
18.1 Introduction
18.2 Microbiology and Food Safety
18.2.1 Microorganisms in Foods
18.2.2 Growth of Bacteria and the Factors that Affect the Growth of Microorganisms
18.2.3 Control of Microbial Growth in Foods
18.3 Food Borne Illness
18.3.1 Types of Food Borne Illnesses
18.3.2 Control of Food Borne Illnesses
18.4 Modes of Disease Transmission
18.4.1 Routes of Disease Transmission
18.4.2 Source of Contamination
18.5 Conditions that Could Lead to Food Spoilage
18.5.1 Categorization of Food on the Basis of their Shelf Life or Perishability and Conditions
that could Lead to Food Spoilage
18.5.2 Signs of Spoilage in Fresh, Dry and Preserved Foods
18.6 Importance of Pest Control
18.6.1 Classification of Pesticides
18.6.2 Precautions to be Taken While Handling Pesticides
18.7 Hygienic Food Handling
18.7.1 Procedures in Food Preparation which Affect the Microbial Count
18.7.2 Cooked Food and Microbial Contamination
18.8 Let Us Sum Up
18.9 Answers to Check Your Progress Exercises

18.1 INTRODUCTION
In our previous unit, we have learnt about plant and equipment maintenance and the
ways by which they can be taken care of. Also, we read in Unit 17 about safety and
sanitation issues that could be a cause of concern if not dealt with caution. This unit
now could be considered a continuation with what we have learnt so far. In this unit
we shall focus on food safety. Issues related to food borne infections and poisoning,
different modes of transmission in food service institutions and conditions that could
lead to food spoilage would be highlighted.

Food contamination with microorganisms is a major source of illness either in the form
of infections or poisoning. You may recall reading about this in Unit 5 in the Food
Microbiology and Safety Course, MFN-003, as well. Negligence on the part of the
food handler can result in a large epidemic. The prime responsibility, as you would
agree to break the chain of transmission of disease from carrier to food and from food
to the consumer lies solely on the food handler. This important aspect has been
covered in the next and final unit. However, you may find certain concepts, topics
included here in this unit and in the next unit repetitive and you might be well aware
of these, as they have already been covered in Food Microbiology and Safety Course,
(MFN-003). Nevertheless, we strongly recommend that you read this unit carefully
and perhaps it would be more useful to study this unit in combination with Units 2,
3 and 5 of the Food Microbiology and Safety Course. This will help you consolidate
your understanding of issues in both worker and food safety.

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Entrepreneurship and Food Objectives
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After studying this unit, you will be able to:
• recall the microorganisms that can cause infection and disease,
• differentiate between food borne infections and poisoning,
• discuss why and how to handle food to prevent infection,
• explain the various modes of disease transmission, and
• describe the conditions that can lead to food spoilage in a food service establishment.

18.2 MICROBIOLOGY AND FOOD SAFETY

You are already aware of the fact that microbiology and food safety are inter-linked.
Many microorganisms are disease-causing yet, some others are beneficial for us in
many ways. Can you think of any examples? Yes, for example moulds are useful to
humans. They are used to ripen cheese and to add flavour and colour to it. At the
same time some moulds are harmful because they produce toxins.

Like moulds, bacteria, viruses etc. are other microorganisms important from food
safety view point. These are briefly highlighted in the subsequent sub-section.

18.2.1 Microorganisms in Foods

Microorganisms, as you must know by now, can be classified into five groups. These
include:
a) Viruses
b) Bacteria
c) Fungi
d) Algae
e) Protozoa
A detail review on these microorganisms is already presented in Unit 2 in the Food
Microbiology and Safety Course. Hence we shall not repeat the review here. But
certainly, we shall like to recapitulate what we have learnt earlier. Quickly go through
the summarization presented herewith. We shall begin with viruses first.
a) Viruses: Viruses are very minute in size, strictly parasitic and cannot be cultivated
outside the living host cell. They feed on living cells of plants and animals and
are pathogenic. Viruses attach themselves to plant, animal or bacterial cells and
the nuclear material present in the virus is released in the cell. At the expenses
of the host the virus multiplies inside the cell. When sufficient numbers of
particles are formed, the cell bursts and the released viruses attack other cells.
Poliomyelitis and infectious hepatitis are viral diseases caused by contaminated
food and drinking water. Shellfish such as oysters, cockles and mussels from
sewage polluted waters can cause viral food poisoning if food is not cooked
thoroughly. Viruses are present in the nose and throat discharges and in the faeces
of infected.
b) Bacteria: Bacteria are found everywhere – in and on soil, water, air, plants,
animals, humans and their food. Bacteria are both useful and harmful to humans.
Can you list down their benefits? They are capable of fermenting sugar to lactic
acid. This makes them important in the manufacture of dairy products like curds,
yoghurt, buttermilk and cheese and fermented vegetable products like sauerkraut
and dill pickles. Some bacteria help in fermenting and curing coffee and cocoa
beans.
Many bacteria are pathogenic to humans and animals. Most food infections and
food poisonings are of bacterial origin. They are also responsible for spoilage of
food. Canned foods, fruit juices and alcoholic beverages are spoiled by acid
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 producing bacteria. They spoil beverages and milk by forming rope or slime in Issues in Food Safety
them. They may cause surface discolouration on many foods or putrefy foods
accompanied with the development of a foul smell. Some of the facts that a food
handler must be aware are presented in Box 18.1.

Box 18.1 Important Facts for Food handlers

The food handler should know that:
1) Bacteria are the most common cause of food poisoning.
2) They are present everywhere.
3) We cannot see them.
4) They do not have legs or wings but are carried from one place to another
by humans animals, water and wind.
5) Under favourable conditions they are present in large numbers.
6) An awareness of how they grow and reproduce is necessary if we want to
control them.
Bacteria live and multiply in many foodstuffs. Very often the type of food, atmospheric
temperature and humidity of the kitchen provide ideal conditions for multiplication of
bacteria. Protein rich foods like meat, fish and poultry, whether raw or cooked, are
excellent media for bacterial growth, especially when these foods are stored without
refrigeration.
c) Fungi: Fungi include the lower plants and are usually multicolour, but the plant
body is not differentiated into roots, stem and leaves. They are saprophytes and
lack chlorophyll. Some may be parasitic. They very in size from the small
microscopic yeasts to mushrooms in the fields. All of them are widely distributed
in nature. Fungi include both yeasts and moulds. Let us get to know both.
Yeast: Yeast are unicellular and are found naturally in soil and dust.
Moulds: Moulds are multicolour. Their bodies are thread-like or filamentous.
Moulds are useful to humans. They are used to ripen cheese and to add flavour
and colour to it. Blue cheese or Roquefort cheese is ripened by Penicillium
roquefort and Camembert cheese by Penicillium camembert. Some species of
Penicillium produce life saving antibiotics. Aspergillums orzo is used for making
soy sauce. Moulds are used in many oriental fermented foods like temper.
Some moulds are harmful because they produce toxins. Aspergillus produce a
toxic substance called aflatoxin when they grow on peanuts, corn, wheat grain and
their meal. Some are parasitic, for example, ringworm is a mould which is parasitic
on skin and hair. Certain varieties of mushrooms growing in the fields are highly
toxic and can cause death, for example, Amanita Sp. Any food with plentiful
mould growth should be discarded.
d) Algae: Algae include both unicellular and multicolour organisms found naturally
in water. They contain chlorophyll and are photosynthetic. Multicultural algae are
of importance as a source of agar for microbiological media. Red and brown algae
are used as a source of food and blue green algae as fertilizers because they are
rich in proteins. Algonac acid and its salts are made from brown algae. This is
used in ice creams to prevent ice crystal formation and to give a smooth texture.
It is also used in cheese and frosting.
A pathogenic algae Gonyaulaux catenulate is found in seawater planktons. Mollusks
who feed on this plankton become poisonous.
e) Protozoa: Protozoan belong to the animal kingdom. They are unicellular. Some
are parasitic.
Pathogenic varieties include Entamoeba histolytica which causes amoebic dysentery.
Trypanosoma causing sleeping sickness and Plasmodium which causes malarial fever.
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Entrepreneurship and Food Amoebiasis occurs when drinking water is contaminated by sewage through
Service Management salads and root vegetables grown on soil to which untreated excreta is applied as a
fertilizer. Entamoeba forms cysts which require heat for their destruction.
Despite of varying characteristics and harmful/beneficial effects, we discussed above,
all microbes have certain common characteristics such as nutrition and oxygen
requirements. Though the nature of these requirements may vary and can be used to
classify bacteria.
Microorganisms require their nourishment by any of the following three methods.
1) By feeding on dead and decaying organic matter. Such microorganisms are called
saprophytes. Bacteria, yeasts and moulds are saprophytic.
2) By feeding on living host cells. Such microorganisms thrive at the expense of the
host and are called parasites. Viruses, some bacteria, some fungi and protozoa
are parasitic on plants and animals.
3) By manufacturing their own food, Green algae contain chlorophyll and can
produce their own food by the process of photosynthesis just like plants.
On the basis of oxygen requirements, microorganisms are classified into three broad
categories. These include:
1) Aerobes: These microorganisms use oxygen to release energy from food, for
example, algae, protozoa and some bacteria like Salmonella which causes typhoid.
2) Anaerobes: These microorganisms obtain their energy without oxygen, for example,
viruses, some fungi and bacteria such as Clostridium causing food poisoning.
3) Facultative Organisms: They can respire either aerobically or anaerobically like
Shigella which causes bacillary dysentery and Staphylococci which causes food
poisoning.

Most microorganisms are harmless to humans. The metabolic wastes produced by

parasitic microorganisms like viruses, bacteria, fungi and protozoa are toxic to living
cells. These poisons or toxins produce the symptoms of disease such as fever,
inflammation, headache, nausea and gastrointestinal upsets.

While talking about microorganism, it would help us to know at what phase of

microbial growth we need to take precautions to prevent food spoilage. Let us have
a look at the growth pattern of bacteria. We have already discussed about it in Unit
2, Food Microbiology and Safety Course, (MFN-003). Let us once again refresh our
understanding of the growth of bacteria.

18.2.2 Growth of Bacteria and the Factors that Affect the Growth
of Microorganisms
Microbial growth as you would know is measured in terms of increase in cell number
and the time period which lapses between two successive cell divisions is called
generation time. It varies in different organisms. The environmental conditions available
also determine the time required for cell division. Many common methods of preserving
food and keeping it fit for consumption depend not on the destruction or removal of
microorganisms but on: (a) delay in the initiation of growth, and (b) hindrance to
growth once it has begun,

Most microorganisms, when added to food, multiply at a very rapid rate under
favourable conditions. A single bacterial cell divides into every 20 to 30 minutes. If
the rate of multiplication is maintained, a single will produce one billion new cells after
a period of 10 hours.

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If the logarithms of the number of organisms (per ml) and the time (in hours) is plotted Issues in Food Safety
on a graph, it is observed that the rate of multiplication is not maintained indefinitely,
but four distinct phases of growth are observed as indicated in Figure 18.1.

Resting phase

Log Of Numbers of Bacteria

Growth
(Log)

Lag
phase Death phase

Time

Figure 18.1: Four phases of bacterial growth

To control bacterial growth, therefore, we must first be familiar with these phases. The
first phase, as you can see, is the lag phase, where there is no growth. The second
phase is the exponential growth phase or log phase in which growth increases at a
very rapid rate and growth rate is highest. The stationery phase is the third phase.
The last phase is the death phase, in which the bacteria die because of a change in
the environment such as: (a) exhaustion of nutrients, (b) accumulation of toxic metabolic
waste products, or (c) alteration of pH etc.

The study of these phases will help us to prevent spoilage of foods at a much earlier
stage, as well as, retard the further growth of microbes. How well we can apply this
understanding to the food industry. This is the focus of the following discussion.

Applications of the Growth Phase to the Food Industry

To prevent spoilage of food it is important that the lag phase are lengthened as much
as possible. This can be achieved by the following ways:
1) by reducing the amount of contamination, i.e. keeping contaminating organisms
away from food.
2) by preventing addition of actively growing organisms which are already in the
logarithmic phase of growth – unclean utensils, containers and equipment that
come in contact with food may harbour such organisms.
3) by providing one or more unfavourable environmental conditions like low
temperature, heat, unfavourable pH, reducing the moisture level, keeping oxygen
away or adding inhibitors etc. The more unfavourable the conditions, the longer
the time required for growth of microorganisms.
4) by actual damage to organisms by processing methods such as heating or irradiation.
To give food the desired storage life and delay the initiation of growth, it is better to
use a combination of methods rather than a single method. Though the best approach
would be not to allow the growth of the microbes. For this, we must be aware of
the various factors that affect the growth and multiplication of microbes. You have
already studied about these factors in Unit 3, Food Microbiology and Safety Course
(MFN-003). Hence, here we shall not go into the details and just list down the factors
to refresh your memory. However, we suggest you look up these in details in the Food
Microbiology and Safety Course for a better understanding.

Factors that Effect the Growth of Microorganisms

Various environmental conditions affect the growth and multiplication of microbes. The
important factors, which have an influence on growth, are listed as:
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Entrepreneurship and Food 1) Food and Nutrients 5) Oxygen
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2) pH level 6) Time
3) Moisture 7) Osmotic pressure
4) Temperature 8) Sunlight or UV rays
Let us now review a few methods, which would control growth of microbes in foods.
18.2.3 Control of Microbial Growth in Foods
Microbial growth in foods can be controlled in a number of ways. When the conditions
necessary for bacterial growth are not available, growth and multiplication will be
restricted. Microorganisms can be prevented from growing by the following methods;
controlling temperature, removing oxygen, adding chemical preservatives, reducing
the moisture content and exposure to ultraviolet rays. A brief review follows.
A) Controlling Temperature
Most microorganisms require a warm temperature to multiply. Pathogenic
microorganisms grow and multiply best at normal body temperature of 37°C. It has
been seen that maximum number of microbes multiplies between the temperature
ranges of 5°C to 60°C (FSSAI). This temperature range is known as the danger zone.
Multiplication slows down towards both ends of the danger zone. Figure 18.2 depicts
the various temperature zones for varying purposes. Here, you can locate danger zone,
45° - 140°F, It is imperative for all food handlers to realize that food should be stored
outside this zone.
Water boils
and most 210
0

bacteria 200
0

killed
(2120F) 1900 Rinse temperature
180 for dishes
0

Internal
(175 -185 F)
0 0
170
0
temperature
for cooked 1600 Machine wash
pork temperature
150
0
(16 F) (145 -155 F)
0 0 0

140
0

Minimum Hand wash water

temperature 130
0
temperature
(135 -145 F)
0 0
for hot food 1200
handling
110
0
(150 F)
0

100
0
DANGER
ZONE! 90
0

Bacteria Room temperature

80
0
(-70 -90 F)
0 0
multiply very
fast 70
0

(450-140F) 600 Dry storage

(-50 -65 F)
0 0

50
0

40
0 Cold storage
(-36 -40 F)
0 0

30
0

200
10
0

Freezer storage
0
0
(-15 -10 F)
0 0

-10
0

-20
0

Figure 18.2: Temperature guide for food safety

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Microbial growth can be contained/controlled as described herewith. Issues in Food Safety

a) Freeing: At low temperatures microbes are not destroyed. Their growth rate is
retarded and so their numbers in food is controlled. When food is thawed and
temperatures become favourable, these microorganisms are capable of growth and
reproduction once again.
b) Heat: High temperatures destroy microorganisms by denaturation of cell proteins
and inactivation of enzymes needed by them for their metabolism. At temperatures
above 63°C bacteria stop multiplying and as the temperature increase, they are
gradually destroyed. The thermal death time (TDT) is the time need at a given
temperature to kill a number of microbes. Heat used to destroy microbes may
be in the form of wet heat or dry heat. Let us understand these two heat
conditions.
• Wet heat: This is more commonly used in the food industry. If carefully
administered, it is a useful method of controlling microorganisms. Wet methods
include pasteurization, cooking and canning.
1) Pasteurization: This method is used to control microorganisms in milk, fruit
juices and wines. Food may be pasteurized by any one of the three methods
listed below:
a) LTH (low temperature holding) method at 62°C for 30 minutes.
b) HTST (high temperature short time) or flash method at 72°C for 15
seconds.
c) UHTS (ultra high temperature sterilization) at temperatures above 135°C
for two seconds. This method makes foods commercially sterile. Such
foods are packed under aseptic conditions and can be stored at room
temperature for three to six months.
2) Canning: In this process, temperatures used are above 100°C. Heating the
food in an autoclave at temperatures between 115°C - 125°C destroys all
microorganisms that could spoil food under normal conditions of storage. The
exact temperature and time required for canning depends on the type of food
to be canned. Acidic foods such as fruit are heated to 100°C only because
acid also helps in preventing microbial growth. A vacuum is created inside the
can or the air in the headspace may be replaced by nitrogen gas to prevent
growth of aerobic bacteria.
3) Cooking (boiling, steaming, stewing and poaching): In these methods of cooking,
wet or moist heat is used. The temperatures attained are 100°C. At this
temperature most microorganisms are destroyed but spores survive. Foods
cooked by these methods cannot be stored for long.
Next, we shall review the dry heat methods.
• Dry heat: It comprises of the following methods.
1) Sun drying, smoking and freeze-drying: In these methods, dry heat is used to
control microorganisms. Dry heat brings about dehydration of the foods or of the
surface of food. It destroys moulds, yeast and most bacteria and spores.
2) Cooking (baking, roasting, and grilling): In these methods of cooking, food is
cooked by dry heat. The temperatures reached on the surface are approximately
115°C. Most bacteria are destroyed. Internal temperature of food is generally
lower.
If food has to be kept for sometime, it should be cooked thoroughly. Foods cooked
by dry heat methods do not spoil as moist heat methods as they lower moisture
content.
Next, let us learn how to prevent growth of microorganisms by other methods.
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Entrepreneurship and Food B) Removing Oxygen
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Removal of oxygen can stop aerobic microorganisms from growing. This can be done
by packing foods in airtight containers or vacuum packing of foods as in canned foods.
However, an aerobic microorganism can still grow in such foods, if these have
been inadequately processed.
C) Adding Chemical Preservatives
These substances retard deterioration of food by preventing microbial growth. Law has
restricted the use of Class II preservatives. If these preservatives are used in foods,
they should be mentioned on the label. They are used to preserve food in the following
ways:
1) They may be added to food, for example, sodium benzoate in tomato sauce and
potassium metabisulphite in lemon squash.
2) They may be applied on the surface of foods. Sulphur dioxide is used on dry fruits
and borax is used to wash vegetables and whole fruit.
3) Wrappers may be impregnated with sorbic acid to prevent surface spoilage of
cheese.
4) The ice used to chill foods like fish may contain tetracycline, an antibiotic that
is a permitted preservative.
5) They may be used as gases around food. Fruits and vegetables are stored in an
atmosphere containing two to three per cent carbon dioxide to retard the ripening
process.
D) Reducing the Moisture Content
The moisture content of food like milk is reduced by evapouration, dehydration or
desiccation of the food. Microorganisms survive in such foods, but they remain
dormant. When such foods are dehydrated, the microorganisms become active once
again. Class I preservatives like sugar and salt are natural substances that bind water,
which is present in the food, and make it unavailable to microorganisms like bacteria.
Moulds and yeasts, which are osmophilic, can grow on such foods. Milk, eggs, fruit
and vegetables are some of the foods, which are preserved by reducing the moisture
content. Such foods can be safely stored at room temperature till they are rehydrated.
E) Exposure to Ultraviolet Rays
Ultraviolet rays are lethal to bacteria. They have poor penetrating power and can be
used only for surface sterilization or for sterilizing the air in a room. They are used
to control mould growth on the surface of bakery products and to prevent spoilage
of meat while tenderizing and ageing.
With a review of the various factors we end our study of the various methods, which
can prevent the growth of microorganisms. What would be the consequences of
microbial growth in foods? Certainly, it would lead to food borne illnesses. Next, let
us get to know about the food borne illness.

18.3 FOOD BORNE ILLNESS

A food borne illness as you already learnt in Unit 5, Food Microbiology and Safety
Course (MFN-003), is a general term applied to all types of illnesses caused by
an organism, substance or material of any kind which is present in food and gains
entrance into the body when such food is consumed.
The cause of contamination is generally faulty handling, poor sanitary practices,
insects, rodents or microorganisms. The sources of contamination of food are shown
in Figure 18.3. The natural decay that occurs in animal or plant tissues is accompanied
by foul odours, and changes in appearance and taste. As the spoilage is visible, people
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reject the food. The main cause for concern is food which is spoilt but where spoilage Issues in Food Safety
is not visibly noticeable. Such food is likely to be consumed and may result in disease.

Spoiled Air
Food Raw
material with
Processing natural
microflora Water
Equipment

Diseased
plants and Soil
animals

Packing Sewage
Materials

Pests Humans

Faeces
Figure 18.3: Causes of contamination
Food may disease by any of the following ways:
1) The food itself may be wholesome but may act as a vehicle of disease
transmission. Pathogenic organisms can be transmitted from one person to another
through many routes like soiled linen, unclean cups, handkerchiefs, door handles
etc. Food handles with soiled hands or on which an ill person or a carrier has
coughed or sneezed, can also cause illness. Diseases like tuberculosis, tonsillitis,
typhoid and influenza can be easily transmitted this way.

2) The food may serve as an ideal medium for rapid growth and multiplication of
large number of microorganisms like Staphylococci and Salmonella. This may
result in food poisoning or food infection. These microorganisms can cause
violet illness of the stomach and intestinal tract. Some of these bacteria release
toxins into the food. The bacteria may die but the toxins formed cause food
poisoning.

Other bacteria do not act until they are consumed alongwith food. They then
cause an infection of the gastrointestinal tract.

3) Food poisoning may be caused by agents other than microorganisms. These

include toxic chemicals, poisonous plants like poisonous mushrooms, insecticides
and pesticides. Toxic metals such as cadmium, zinc, lead etc., or excessive use
of mono sodium glutamate in Chinese food may lead to severe reactions. Some
individuals may show abnormal sensitivity to certain foods and develop allergies.
Common food allergens are egg white, shellfish and strawberries.

Food-born hazards may thus result from microbial action, toxic metals and
pesticides, animal parasites, natural poisons in foods are allergic reactions of a person
due to sensitivity to a particular food. The food borne illnesses are summarized in
Table 18.1.

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Entrepreneurship and Food Table 18.1: Food borne illnesses at a glance
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Bacterial Food Poisonings or Intoxications
1. Staphylococcus food intoxication 3. Bacillus cereus food poisoning
2. Botulism 4. Perfringens food poisoning
Bacterial Food Infection
1. Salmonellosis 6. Campylobacter Infection
2. Typhoid and Paratyphoid 7. Streptococcal Infection
3. Bacillary Dysentary 8. Brucellosis
4. Cholera 9. Listeriosis
5. Enteropathogenic Infection
Viral Infections
1. Infectious Hepatitis 2. Influenza
Parasitic Infestations
1. Amoebiasis 4. Giardiasis
2. Trichinosis 5. Roundworm Infestation
3. Tapeworm Infestation
Naturally Occurring Toxicants in Foods
1. Lathyrus Sativus 5. Cereals and Groundnuts
2. Soyabeans 6. Poisonous Mushroom
3. Green Potatoes 7. Mussels and Clams
4. Argemone Oil 8. Ergot
Toxic Metals and Chemicals
1. Selenium 8. Tin
2. Zinc 9. Brass
3. Arsenic 10. Fluoride
4. Lead 11. Barium
5. Cadmium 12. Mercury
6. Cobalt 13. Pesticides
7. Copper
Food Allergies
1. Eggs 4. Chocolates
2. Shellfish 5. Strawberries
3. Peanuts

Let us review these food borne hazards briefly.

18.3.1 Types of Food Borne Illnesses

Of all the food borne hazards listed in Table 18.1 above, diseases caused by microbial
action in food are most widespread. Microorganisms cause food poisoning and food
infection and animal parasites cause infestation. Hygienic handling of food and good
personal hygiene can control all these. Microorganisms, which cause food borne
illnesses, are bacteria, viruses, protozoans and nematodes, as already mentioned earlier.
Among all these microorganisms, bacterial contamination is the most common cause
of food poisoning in the catering industry. It usually results from mishandling of food.
These illnesses are characterized by a severe disturbance of the stomach and intestines,
which occurs after consuming food in which the offending bacteria were given a
chance to multiply. Such illnesses are broadly divided into two categories: food
poisoning and food infection. Let us get to know about them.
a) Food Poisoning
Food poisoning or food intoxication is an illness caused by toxins present in
contaminated food. The toxin may be a poisonous chemical toxin, which is accidentally
or intentionally, added, a naturally occurring poison like solanine in green potatoes or
a toxic metabolite excreted by bacteria. Some important facts about food poisoning are
420 highlighted next.
 Issues in Food Safety
SOME IMPORTANT FACTS
• Food poisoning causes more than 23 million lost working days in a year.
• The number of reported cases has doubled in the last ten years.
• In spite of more public awareness about hygiene, food poisoning is on the
increase.
• The standard of food hygiene in most establishments is very poor.

In bacterial food poisoning the toxin is produced during multiplication cells. When food
is consumed, the toxin already present irritates the lining of the stomach and causes
vomiting. If the toxin reaches the intestine, it may cause abdominal pain and diarrhoea.
The incubation period for such food poisonings is comparatively shorter (one-six hrs)
than that for bacterial food infections. The offensive food may not contain any living
bacteria, which may have been destroyed during heating.
Toxins need much higher temperatures to be destroyed than the bacteria, which
produce them. They may thus be present in inadequately heated foods, even if the
bacteria have been destroyed. However, some food poisonings occur only when large
numbers of live bacteria are ingested. When these bacteria reach the intestinal tract
they produce the toxin, for example, Clostridium perfringens. Refer to Table 18.2,
which summarizes some common bacterial food poisoning. The causative agent, main
source of infection, food involved and preventive measures are highlighted.
What are food infections? Let us get to know about them.
b) Food Infections
Food infection is an illness caused by microorganisms. It results from the consumption
of food that contains living bacteria, which are multiplying and capable of producing
disease. The illness, which results, is the reaction of the body to the presence of
microorganisms or to their metabolites. The gastric juices secreted in the stomach are
acidic and destroys some bacteria. In the small intestine the pH is neutral and bacteria
multiply rapidly. This irritates the lining of the intestines, resulting in nausea, diarrhoea
and abdominal pains. The incubation period for an infection to occur is 12 hours or
more.
For bacteria must be present in food. It is likely that food could be contaminated with
several hundred causative bacteria. If conditions for growth are favourable, these
bacteria could multiply to over one million in a short span of three to four hours.
The time lapse between the consumption of food and the appearance of symptoms
is called the incubation time. The incubation time and the severity of the attack of
bacterial poisoning or infection will depend on several factors . Refer to Table 18.2,
once again which summarizes some common bacterial food infections. The causative
agent, main source of infection, food involved and preventive measures are highlighted
as such.
As mentioned earlier besides microbial action the food borne hazards may also result
from toxic metals and pesticides, animal parasites, natural poisons in foods and allergic
reactions of a person due to sensitivity to a particular food. Let us briefly review these.
c) Naturally Occurring Toxicants in Food
Besides food poisoning and food infections, certain plants and animals contain natural
substances that are poisonous and may produce gastrointestinal disturbances. Some
may even prove fatal. These naturally occurring toxicants in food are summarized in
Table 18.3. A detail review of the naturally occurring toxicants, as you may already
know, is already included in the Food Microbiology and Safety Course (MFN-003)
in Unit 7. You may have already gone through the unit. Hence, we shall not dwell
further.
Next, let us briefly review the toxic metals and chemicals.
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d) Toxic Metals and Chemicals Issues in Food Safety

Metals, when consumed in excess of the requirement, could cause toxicity. These
contaminants may be present in the environment and may accumulate during the
different stages of food preparation. By the time food is ready to be consumed, it can
reach levels, which are toxic to humans. Some of the toxic metals are listed in Table
18.4. Table 18.4, in fact presents an outline of all toxic metals and chemicals their
toxic effect and the food involved. For a detail review we suggest you look up Unit
7 in the Food Microbiology and Safety Course (MFN-003). Perhaps you may have
already done that.
Finally, a word about food allergies.
e) Food Allergies
An allergy is defined as a special reaction of an individual to some ingredient of food.
Some people show abnormal sensitivity to foods that are harmless to a non-allergic
person. The substance that causes the allergy is called an allergen. Allergens may be
present in foods like eggs, wheat, fish, shellfish, chocolate, strawberries and cow’s
milk. You may recall studying about food allergies and their management in the
Clinical Nutrition and Therapeutic Course (MFN-005) in Unit 6. As described in this
unit, symptoms of allergies vary from urticaria or hive to gastrointestinal upsets and
may be mild to extremely severe. The food responsible for causing the allergy should
be avoided.

In the catering industry, the service staff should have basic knowledge of various
recipes in the menu in terms of ingredients used, so as to guide the customers about
food selection in case of allergy. Next, let us find out how can we control these
illnesses.

Having reviewed the food borne hazards, let us next get to know of measures which
can be adopted for the control of the food borne illnesses.

18.3.2 Control of Food Borne Illnesses

Food borne diseases are generally transmitted through careless food handlers who are
either suffering from the disease or are carries of microorganisms. A healthy food
handler may transmit microorganisms indirectly through cross-contamination. These
diseases are a constant threat to the food industry. Practicing the basic principles of
hygiene listed herewith can prevent them:
1) Food should be handled in a hygienic manner by all food handlers and infected
handlers should be kept away.
2) Cross-contamination from raw to cooked foods can be prevented by washing
hands and all equipment or surfaces in contact with raw food.
3) The time gap between preparation and service of food should be reduced to avoid
long storage in a warm environment.
4) Large masses of food, which have to be reheated later should be cooled quickly
to 15°C and refrigerated immediately.
5) Food should be reheated thoroughly so that the center of the food gets heated
to temperatures high enough to destroyed bacteria.
6) Frozen foods should be thawed carefully at temperatures between 10 to 15°C
and frozen food should not be refrozen unless it has been cooked well after
thawing.
7) Cooked foods, which are to be served hot, should be stored above 63°C. Avoid
cooling and heating food repeatedly.
8) Leftover food should be refrigerated immediately to keep it out of the danger
zone. 429
Entrepreneurship and Food 9) Food should be prepared in quantities required and quantities for which adequate
Service Management refrigerated storage space is available. This will prevent perishable or high risk
from spoiling.
10) Suspect food should be discarded immediately without tasting it.
11) The kitchen and cooking equipment should be cleaned daily and regular pest
control measures should be taken.
12) Adequate toilet and washbasin facilities with a continuous supply of water should
be provided.
13) High risk foods like meat, poultry, eggs and milk should be purchased from
certified dealers only.
With a word on how to control the food borne illnesses we end our study on food
borne illnesses. Next, we shall focus on the mode of transmission of diseases, since
in the food industry this has a direct impact on food and worker safety.

18.4 MODES OF DISEASE TRANSMISSION

A communicable disease is an illness caused by a specific infectious agent or its toxic
products. The disease occurs through transmission of that agent or its
products from the source to the susceptible host either directly or indirectly. It includes
contagious, as well as, infectious diseases.
A carrier is a person who harbours a specific infectious agent in the absence of
obvious signs and symptoms of the disease and serves as a potential reservoir of
infection for other people. Carriers are either temporary carriers or chronic carriers
as enumerated herewith:
1) Temporary Carriers: They excrete the organism only for a short period of time.
Temporary carriers may be of three types:
a) Incubatory Carriers: These carriers shed the organism during the incubation
period of the disease.
b) Convalescent Carriers: These carriers continue to excrete organisms during
the period of convalescence.
c) Healthy or contact Carriers: These carriers acquire the disease producing
organism without suffering from the disease and may continue to excrete the
disease agent for variable periods.
2) Chronic Carriers: They harbour and excrete the disease-producing organism for
indefinite periods. The duration of the chronic carriers state varies with the
disease. For example in the case of typhoid, the carrier state lasts for several
years, whereas in chronic dysentery the carrier state lasts for one year or more.
From the point of view of spread of disease, chronic carriers are a far more important
source of infection than people who are actually suffering from the disease. This is
because chronic carriers are difficult to identify and it is likely that they may be
handling food and spreading infection unknowingly.
The first known chronic carrier of typhoid fever was Mary Mallon, often referred to
as Typhoid Mary. She worked as a cook in New York and infected at least 53 people
with typhoid fever in the early 20th century, before she could be identified as the
source of infection and removed from the job.
Another mode of transmission of diseases is through cross-contamination. Let us get
to know about it.
Cross-contamination
Harmful microorganisms present in one food can contaminate another food. This
430 process is known as cross contamination and is defined as the transfer of bacteria
from something dirty to something clean, or from a food with many bacteria to a Issues in Food Safety
food with fewer bacteria, by means of a non-food vehicle such as:
1) Chopping boards, knives, utensils and equipment,
2) Work surfaces, dish cloth etc,
3) Hands of the food handler,
4) Drops of liquid oozing from contaminated food, and
5) Infected droplets from cough and sneeze.
Cross-contamination can occur whenever clean and dirty operations are mixed or if
the same equipment is used for handling raw and cooked meat without cleaning and
sanitizing it between use. Raw meats and its juices contain many bacteria, which are
transferred to cooked meat by using the same equipment. Cross-contamination of
cooked meat can be prevented by:
1) Storing raw and cooked meat separately and not next to or on top of each other,
to prevent drops of liquid oozing.
2) Colour coding equipment such as chopping boards and knives for handling only
one type of food, for example using pink for raw meat and poultry and brown
for cooked meat and poultry.
3) Preparing cooked and raw meats on separate tables.
Can you list a few examples, which could lead to cross-contamination? Well, there
could be many examples of cross-contamination, but simple handling of equipment,
utensil, as enumerated herewith could be detrimental:
1) When a dishwasher places clean and sanitized plates on a table reserved for dirty
plates, the plates get contaminated.
2) When a busboy brings used plates to the dishwashing machine and picks up clean
plates without washing his hands, the clean plates get contaminated.
3) When the chef places a dirty cardboard box on a food preparation table, the table
gets contaminated and any food kept on that table will also get contaminated.
Even when a potentially hazardous food gets contaminated, it does not become
harmful immediately. Remember, the bacteria transferred to the food need time and
a warm temperature to multiply before the food can cause a food borne illness
when consumed.
In fact, besides the carriers and cross-contamination, in a food service establishment
diseases may be transmitted by many routes. These are highlighted in the subsequent
sub-section.

18.4.1 Routes of Disease Transmission

Diseases may be transmitted by more than one route. The common routes of transmission
are:
1) Contact transmission: by direct or indirect contact with the source of disease.
2) Vehicle transmission: where milk, water and other foods act as vehicles for
transmitting disease.
3) Vector transmission: by insects and other invertebrate hosts that transmit infection
by inoculation into the kin, by biting or by depositing infective material on skin,
food and other objects by their feet and bodies or by regurgitating on food.
4) Air-borne transmission: by droplet infection, droplet nuclei and infected dust.
Droplet infection can occur when a person sneezes or coughs and expels particles
of moisture containing a large number of organisms, up to a radius of 1 meter
or more. When the moisture from smaller droplets evaporates, a minute particle
of virus or bacteria which are called droplet nuclei, remain suspended in the air. 431
Entrepreneurship and Food 5) Infected dust: larger droplets of moisture settle down on the floor and become
Service Management a part of dust. During dusting or sweeping these dust particles become air- borne
and get inhaled or settle on uncovered food and drink.
In fact disease could be transmitted through food either directly or indirectly. Let us
find out how.
Direct and Indirect transmission
Disease is transmitted through food either directly or indirectly. In direct transmission
of disease, the pathway illustrated in Figure 18.4, is involved.
Coughs and sneezes
(Respiratory tract)

The food handler Open Sores Prepared Food Food is

(Diseased or Carrier) cuts, boils (Skin)
consumed

Soiled hands Illness results

(Intestinal tract)

Pathogens are
excreted
Figure 18.4: The direct transmission of disease

Let us get to know about it.

• Direct Transmission: The food handler transmits pathogens to food. Because of
coughing or sneezing on or near the food, droplets containing microorganisms may
fall on the food.
Unwashed or improperly washed hands transfer diseases of the intestinal tract.
If hands soiled with faecal matter handle food, disease-causing agents are transferred
to the prepared food. Consumption of such food causes illness. When food is
openly displayed, the customer handling the food can contaminate it.
• Indirect Transmission: The host of communicable diseases may transmit
pathogens indirectly through various routes onto prepared food and from there to
other people consuming the offending food as highlighted in Figure 18.5. The
other indirect routes of transmission of disease causing agents or pathogens are
through:
1) contaminated utensils and equipment,
2) sewage polluted water and food grown on polluted soil or through faulty
plumbing,
3) soiled linen, door handles and taps,
4) insects like flies and cockroaches,
5) rodents like rats, mice, and
6) infected animals and their products.
Disease causing various routes of indirect Food is consumed
agents transmission
(listed above)
Illness results

Pathogens are excreted

Figure 18.5: The indirect transmission of disease

432
Food may also be contaminated through unclean utensils and equipment as already Issues in Food Safety
mentioned earlier. The pathogenic organisms eliminated from the human body are
found in sewage is mainly faecal matter. If untreated sewage is allowed to drain into
any drinking water, the water, as well as, fish breeding in such waters gets contaminated.
Salad vegetables, roots and tubers are at a greater risk of contamination as they are
consumed raw and because they are in direct contact with the soil. Rats, mice, flies
and cockroaches can also transmit disease. They live in sewers and garbage dumps.
Un-pasteurized milk and meat from diseased animals can transfer pathogens of animal
origin.
What could be the sources of contamination of food that would eventually lead to its
spoilage? Let us know about this, next

18.4.2 Source of Contamination

Food can be contaminated or spoilt by any of the following sources and at any stage
from the farm to the table till it is consumed. Sources of contamination of food include:
air, water, plant, soil, food handler, machinery and equipment, sewage and trucks or
carts during transport.
Contamination of food results in the spoilage. Food spoilage can be broadly classified
into six groups. Foods spoil mainly because of any one or more of the following
reasons. Let us see what are these.
1) Microbiological action: Microorganisms are present everywhere and in all the
sources of contamination mentioned above. These organisms can contaminate
food and spoil it. Milk turns sour because of bacterial action, yeasts ferment fruit
juices and mould grows on bread, which has to be discarded. Microbial growth
in foods may be obvious like the example listed above. Some bacteria, which
cause food poisoning or food infection, may contaminate food, which is
unhygienically handled. In such cases, microbial growth may not be obvious. Not
all microorganisms can cause disease, in fact some are useful to the food industry.
Foods having a high protein, moisture, vitamin and mineral content are an ideal
media for bacterial growth.
2) Presence of contaminants: If any unwanted inedible matter is added to or is
present in foods, the food is said to be spoiled and should be rejected. Contaminants
present in food could be nail chippings, hair stones, grit, dirt or other extraneous
matter. Accidental contamination by metallic fragments and shards of glass may
render food harmful. Some common metal fragments are stapler pins, flexible
aluminum wire, metal curls and fine filings from canned food opened with a
defective opener. Glass chips may enter food from broken glassware or misuse
of glass for taking out crushed ice.
Radiation used for preserving spices and those emitted by microwave ovens,
although invisible, may also prove hazardous to health if used in excess. This kind
of contamination occurs at any stage right from harvesting to food service
3) Action of insects: Foods are spoilt because of the presence of worms, weevils,
fruit flies, moths etc. These may damage the food and reduce its nutrient content.
Food spoilt by insects is not fit for human consumption. The presence of insects
or insect body fragments or droppings in food served to customers is highly
objectionable and will affect the reputation of the catering establishment.
4) Natural enzymes: Foods spoil by autolysis or the action of various enzymes
naturally present in them. After picking or harvesting, fruits and vegetables remain
alive for sometime. They respire and ripen and if they are not consumed or
processed soon they become over-ripe and ultimately spoil.
Enzymes naturally present in meat act on mutton fibers and bring autolysis. If
these natural changes are not controlled, foods may spoil. As action of enzymes
is influenced by temperature, refrigeration will retard the action and blanching will
destroy the enzyme. 433
Entrepreneurship and Food 5) Physical changes: These changes occur in food by freezing, desiccation, evaporation
Service Management and absorption of moisture. Freezer burn is a physical change seen in deep frozen
foods.
Mechanical damage during harvesting and transporting foods, like bruising and
crushing of fruits and vegetable, broken eggs and cracked shells, can accelerate
spoilage by microorganisms because of easy access. It also results in greater
susceptibility to decay and discolouration by enzyme action. This can be prevented
by proper storage and transport facilities.
6) Chemical reaction: Chemical changes, which are not catalyzed by natural enzymes
or action of microorganisms, can also result in chemical spoilage of foods. A
reaction between acidic food and iron from the can causes hydrogen swell in
canned foods. Development of oxidative rancidity in fats and the fatty phases of
foods results in spoilage of fried snacks and oil-based pickles. Other changes
include oxidative discolouration, flavour changes and nutritive loss.
Spoilt food can cause a great financial loss to the catering establishment. Spoilt food
is best discarded. However, bacteria causing food poisoning may soil the food without
showing any visible signs of spoilage. The caterer should take utmost care to prevent
spoilage from occurring. It is best to remember that once a food is spoilt, no amount
of cooking, freezing or proper handling can make the food fit for consumption.
In this context therefore it is important for us to understand or know about the
conditions that lead to spoilage. These are described in the next section.

18.5 CONDITIONS THAT COULD LEAD TO FOOD

SPOILAGE
We have already learnt about various modes of transmission of diseases caused due
to infections agents, or their products. Also, we saw the sources of contamination.
Next, how do we find out whether a food is suitable for consumption or not? We will
soon find out by going through the discussion presented herewith in this section.
A food is wholesome and it fit for consumption if the following criteria are fulfilled.
1) Food should be at the desired stage of development, or maturity, for example,
fruits should not be over-ripe.
2) Food should be free from pollution at any stage in production or handling, for
example, vegetables grown in areas fertilized by sewage should not be consumed.
Food handed by dirty and/or diseased workers, should be discarded. Food
contaminated by files or rodents should be considered as suspect food.
3) Food should be free from objectionable changes resulting from microbial
attack or action of enzymes in the food.
So then what is spoiled food and what are the conditions that could lead to spoilage.
Let us find out.

18.5.1 Categorization of Food on the Basis of their Shelf Life or

Perishability and Conditions that could Lead to Food
Spoilage
You would have realized that all foods don’t spoil at the same rate and to the same
extent. Certain foods like fruit and vegetables spoil more as compared to cereals, pulses
etc. Why so? This is because based on this characteristic; foods can be categorized
in to three main groups on the basis of their shelf life or perishability.
1) Non-perishable or stable foods: These foods do not spoil unless they are handled
carelessly. They should be stored in a cool, dry place. They can be stored for
434
 one year. They should be picked and cleaned before storage. If necessary, grains Issues in Food Safety
can be washed with water to remove any dust and dirt sticking to them. These
should then be dried in the sun, allowed to cool and stored in containers with tight
fitting lids.
Non-perishable foods include sugar, jaggery hydrogenated fat, vegetable oil,
ghee, whole grains, dals, whole nuts, dry salted fish and meat, papads, canned
foods, preserves such as pickles, jams and murabbas.
2) Semi-perishable foods: These foods do not spoil for a fairly long time, if stored
properly. They are less likely to decay due to microbiological contamination than
other perishable foods. Natural chemical breakdown is also slower in such foods.
If they are stored in a cool place with adequate ventilation, they have a moderately
long shelf life. Use of proper containers is equally important. Semi-perishable
foods include processed cereals, pulses and their products like flour, Bengal
gram flour, millet flour, semolina, parched rice, popcorn etc. Their shelf life
depends on the storage temperature and moisture in the air.
Other semi-perishable foods are potatoes, onions, nuts, frozen foods kept solidly
frozen at “zero” to 18°C and canned foods that need refrigeration, apples, citrus
fruits, pumpkin etc. Foods in this group can be stored for a week to a couple
of months at room temperature without the development of any undesirable
changes in flavour and texture.
3) Perishable foods: This is the largest of the three groups and includes most of
the food items we consume everyday, such as milk and products, eggs, poultry,
meat, fish, most fruits and vegetables such as bananas, pineapple, papaya, green
leaf vegetables etc. As these foods contain high amounts of protein, moisture and
other nutrients, they are an ideal medium for bacterial growth. They also spoil
easily by natural enzymatic changes. They have a very short shelf life of a few
hours to a few days, after which they spoil rapidly. It is this group which is
responsible for the outbreak of food-borne illness.
This group also includes all prepared menu items, opened canned foods and frozen
foods, which have thawed. Foods in this group must be stored at low temperatures
to retard the action of microorganisms and enzymes.

With a brief review of foods categorized into three main groups on the basis of their
shelf life or perishability, next let us get to know about the conditions that could lead
to spoilage.

Conditions that could Lead to Food Spoilage

Foods spoil easily if they are improperly handled. To prevent spoilage in foods, it is
necessary that care should be taken to ensure purity, wholesomeness, taste and
attractiveness of foods and beverages served. Food spoilage is hastened if conditions
are favourable for microbial, enzymatic and chemical contaminants and insect action
or if food is mechanically damaged.

Therefore, it is essential that foods are stored well. The following conditions could lead
to spoilage of foods:
1) buying more food than required,
2) buying poor quality commodities due to lack of accurate purchase specification,
3) insufficient inspection of incoming commodities,
4) lack of promptness in storing delivered items,
5) inadequate storing facilities,
6) failure to separately store dairy products, meats, vegetables, and prepared foods,
7) failure to maintain refrigerators and freezers in good operating condition,
435
Entrepreneurship and Food 8) negligence in maintaining storage areas is a sanitary condition at all times,
Service Management
9) insufficient training and supervision of personnel handling the food.
Next, what signs to look for to identify the spoiled foods? Let us find out.

18.5.2 Signs of Spoilage in Fresh, Dry and Preserved Foods

The signs of food spoilage vary with the type of food, the cause of spoilage and the
environment. One can cause spoilage or more of the different factors mentioned
earlier.
Signs of spoilage generally seen in foods are: softening, hardening, discolouration,
mould growth, fermentation, drying, oozing out of liquid, off odours such as mouldy,
alcoholic putrid, and presence of insects.
Let us then review the spoilage indicator in different categories of food.
Spoilage Indicator in Different Categories of Food
The various spoilage indicators in variety of foods are enumerated herewith.
a) Canned Food: Although canned food have excellent keeping quality because the
contents of the sealed cans are practically free from microorganism, some heat
resistant spores may remain or bacteria may enter cans which are not properly
sealed. If cans are stored at warm temperatures these heat resistant, anaerobic
spores or bacteria may germinate, multiply and spoil the contents of the can.
Sometimes the acid from the food reacts with iron of the container and spoils the
food by forming hydrogen gas. The spoilage of canned foods result either from
chemical or microbial spoilage or both.
Signs of possible canned food spoilage are:
• a puffy, swollen appearance because of bulging ends.
• leaky, corroded or rusty cans.
• contents spurt out when the can is opened.
• contents smell putrid or of hydrogen sulphide.
• brine or syrup looks cloudy, bubbly, slimy or mouldy.
• contents are discoloured.
Note, canned food which is doubtful should be discarded without tasting the contents.
b) Frozen Foods: It is hard to detect spoilage in frozen foods unless there are
changes in colour and smell. However, if the following precautions are taken food-
borne illnesses can be prevented.
• Do not use frozen foods if off smell, taste or discolouration is there,
• Do not re-freeze food which has been thawed,
• Thaw only what you need,
• Do not purchase unsound packages,
• Do not keep frozen food out of the freezer for long before cooking or serving,
and
• Do not accept food which has a large quantity of ice crystals formed inside
the packets.
Note, frozen foods do contain some bacteria as freezing only retards bacterial growth
and does not kill them. Bacteria multiply when food has thawed and is in the danger
zone. Therefore, once frozen foods are thawed, they are highly perishable.
c) Fish: Spoilt fish shows the following signs:
• dull or sunken eyes
• gills are grey or green
• off odour
436
 • flesh separates from the bone and is flabby Issues in Food Safety
• depression remains in flesh when outer skin is pressed
• few scales are left on fish
• shellfish claws and tail lose their spring
d) Meat and Poultry: Bad meat shows the following signs and spoils more
readily when more surface area is exposed, as in minced meat. These signs include
discolouration, putrid smell and slimy appearance and feel. Organ meats such
as liver, kidney and brain are more perishable than muscle meat.
e) Eggs: Stale eggs float in water. The eggshell is the spoilage indicator in whole eggs.
Spoilt egg shows the following signs:
• Cracked Shell
• Leaking contents
• Egg yolk is exposed
• Shell has a dirty discoloured appearance
• Blood spot, meat spot, foul odour or other contamination
f) Milk and Dairy Products: Milk and milk products, which are unfit for
consumption may show any one or more of the following changes:
• Change in taste to sour or bitter, fat separates out into clumps, milk curdles
when heated, butter tastes rancid
• Change in smell
• Rope formation
• Discolouration
• Cheese and curds develop off odours, mould growth and become a little slimy
g) Cereals and Pulses: Although they do not spoil easily, signs of spoilage are:
• Musty odour and off flavour
• Presence of weevils, beetles, moths and worms
• clumping of wholegrain
• presence of dirt, mud and stones
h) Vegetables and Fruit: These show the following signs of spoilage:
• presence of mould, leading to rot
• green leafy vegetables are wilted and limp
• discolouration and mushy texture
• presence of insects and worms
• green potatoes, sprouted potatoes and over mature vegetables
• skin or peel is damaged or bruised
i) Cooked Foods: These foods are at high risk of getting spoilt. They show various
signs of spoilage or may not show any visible signs and yet harbour microorganisms
capable of causing food borne diseases. Leftover should be stored carefully and
doubtful food should not be consumed. Very often there are no obvious signs of
spoilage in cooked foods.
In the discussion so far we have focused on the point that following several basic rules
to protect food from contamination can prevent food spoilage. Spoilage of food
depends upon the perishability of food. The food handler should be able to select
wholesome food and identify likely signs of spoilage in food. Now answer the
questions included in the check your progress exercise 1.

437
Entrepreneurship and Food
Service Management Check Your Progress Exercise 1
1) How does a food handler transmit a food borne illness directly?
................................................................................................................
................................................................................................................
................................................................................................................
2) List the factors that facilitate the growth of bacteria.
................................................................................................................
................................................................................................................
................................................................................................................
3) Name the types of chemical food poisoning. How can they be prevented?
................................................................................................................
................................................................................................................
................................................................................................................
4) State whether true or false.
a) All food borne illness can be prevented.
b) Protein rich foods are an excellent medium for bacterial growth.
c) Leftover food should always be mixed with fresh food for economical
reasons.
d) Brass pots and pans should be lined with tin.
5) Differentiate between food poisoning and food infection.
................................................................................................................
................................................................................................................
................................................................................................................

Besides being able to identify wholesome safe food, it is important that a food handler
practices hygienic food handling practices. A detail review on this aspect is presented
in section 18.7. Before we move on to this section we would also like to bring to your
notice the importance of pest control in a food service operation since we have already
learnt earlier that food contamination leading to food poisoning and other serious
diseases in humans, is a major hazard of a pest infestation.

18.6 IMPORTANCE OF PEST CONTROL

The importance of pest control in food service operation is highlighted herewith.
1) Contamination: Food contamination leading to food poisoning and other serious
diseases in humans is a major hazard of a pest infestation. This is so because pests
move from dirt to food and transfer harmful microorganisms to it.
2) Legal requirement: According to the Prevention of Food Adulteration Act (1954),
if any food article consist either wholly or in part of any filthy, putrid, rotten,
decomposed or diseased animal or vegetable substance or is insect infested or is
otherwise unfit for human consumption, it is deemed to be adulterated. Serving
adulterated food is punishable by law.
438
3) Wastage and destruction: Ten per cent of the world’s harvested cereals are Issues in Food Safety
destroyed by rodents and insects, which if saved could feed 260 million people.
Rodents are known to destroy pipe, insulation and cables. Termites and textile
pests cause grave damage to the woodwork and upholstery. Beetle, weevils and
warehouse moths destroy commodities, making them unfit for consumption.
Rodents contaminate much more food with their hair and droppings than they
actually eat.
4) Reputation: The reputation of any catering establishment depends largely on the
prevailing hygienic conditions. Flies hovering over uncovered food and insect body
parts and droppings found in food can be very repulsive to the consumer, thus
damaging the establishment’s reputation. Hence, proper sanitary practices and pest
control measures would go a long way in building up goodwill among customers
and in turn will improve financial gains.
Having looked at the importance of pest control, let us get to know about pesticides
and the different types.

18.6.1 Classification of Pesticides

Pesticides include insecticides and rodenticides. They are substances, which have
certain pharmacological effects on insects and rodents, either as poisons or as
repellants. Pesticides that are reliable, easily available, have a prolonged residual effect
and are not highly toxic to humans are preferred. Pesticides can be categorized on the
basis of the nature of the substances, their effect on pests, and method of application.
Let us learn how.
A) Nature of the Substances: Under this category, pesticides can be divided into
three types as inorganic, organic and synthetic pesticides. Let us get to know them:
1) Inorganic pesticides: These are natural chemical substances, for example, sulphur
dust, arsenic, hydrogen cyanide and Paris green.
2) Organic pesticides: These are mainly plant extract. They are least harmful and
are also least effective against insects, for example, parathyroid. They have a
quick ‘knok-down’ action but little residual effect hence repeated applications are
necessary.
3) Synthetic pesticides: As the name implies, these are manmade chemicals, are
highly dangerous and should be stored away from food preparation areas. They
include chlorinated hydrocarbons like Lindane, DDT and chlorophyriphos; organo-
phosphates like malathion, phosphine and diazion and carbomates like carbandazim,
aldicarb and carbaryl.
B) Effect on Pests: Based on this criterion, pesticides can be divided into six types.
What are these? Let us see next.
1) Stomach poisons: These are applied to plants and ingested by insects while they
feed on these plants, for example, arsenic, fluorides.
2) Contact poisons: These are applied directly to pests. They penetrate and damage
the insect body wall, for example, DDT, BHC (benzene hexachloride) and indiara.
3) Residual poisons: These are applied to surfaces. Inspects touching them pick up
a lethal does for example, DDT and BHC.
4) Systemic poisons: These are applied to plants and animals. These poisons are
absorbed and translocated to all parts of the organisms, so that insects feeding on
them acquire a lethal does.
5) Repellants: These keep insects and other pests away from a given area, due to
the odour they emanate, for example, Dimethyl phthalate (DMP), Dibutyl phthalate
(DBP) and Tulsi leaves.
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Entrepreneurship and Food 6) Fumigants: These poisons are inhaled by pests and cause death, for example,
Service Management hydrocyanic acid gas and sulphur dioxide.
C) Method of Application: This is the third criterion for classifying pesticides. Let
us see, what are the different types under this classification method.
1) Sprays, for example, lindane, pyrethrum
2) Pellets, for example, boric acid, naphthalene
3) Chalk coated or impregnated with insecticidal powder or dust
4) Dusts, for example, BHC, DDT
5) Meals, for example, zinc phosphide, warfarin
6) Vapours, for example, lindane, DDVP (dichlorvos), hydrocyanic acid
7) Lacquers, for example, insecticides mixed with lacquers, paints, and varnishes;
these are effective for at least a year
8) Liquids, for example, kerosene, mineral and tar oils
9) Aerosols: They contain liquefied gas, for example, Freon, under pressure, which
when released after the valve of the dispenser is opened, lets off the insecticidal
solution mixed with it, for example pyrethrins, DDT.
After having knowledge about what are pesticides and their classification, let us have
a look at the precautions that must be taken while handling pesticides.

18.6.2 Precautions to be Taken While Handling Pesticides

All pesticides are toxic to humans. Hence forth, use of certain pesticides has been
banned. These are given in Table 18.5, for your reference. Food service workers need
to be adequately instructed regarding the hazards involved and should be trained to
avoid them.
These are some of the precaution needed: -
1) Using gloves and masks while handling these chemicals is essential.
2) Wash hands thoroughly after use.
3) Never use sprays when food is openly displayed.
4) Storage of insecticides away from food articles. Holding these poisons in a
separate area with their proper labels is important to avoid accidental poisoning.
Also, they are to be kept away from heat and open flames.
5) Knowledge of the type of pesticides banned and the specific residual limits
permissible in food commodities as laid down by the Government of India is
essential.
6) First-hand knowledge of antidotes to various poisons is necessary for food service
workers.
Table 18.5: Pesticides banned by the Government of India
1) Aldrin 8) Pentachloron-nitrobenzene
2) Chlordane 9) Methyl parathion
3) Hetachlor 10) Nitrofen
4) Dibromo-chloropropane 11) Parquet dimethyl sulphate
5) Toxaphene 12) Nicotine sulphate
6) PCP 13) Tetradifon
7) PMA

Use of DDT in agriculture and BHC on vegetables, fruits and oiled crops and in
preservation of grains have also been banned because their safety is doubtful.
440
Table 18.6 suggests a few pesticides that have been recommended in kitchen against Issues in Food Safety
particular pests.

Table 18.6: Pesticides recommended for use in the kitchen

Pest Pesticide Recommended

1) Cockroaches Pyrethrum extract, malathion, Indiara
2) Flies Pine oil, cypermethrin, Indiara
3) Ants Cypermethrin, malathion, Indiara
4) Silverfish Cypermethrin, malathion
5) Stored grain insects Ethyl dibromide (EDB), mercury tablets, castor
oil, neem guard, boric acid, tulsi leaves
6) Rats and mice Warfarin, bromadiolone

The non-poisonous nature of organic pesticides (Indiara, neem guard) calls for their
extensive use in kitchens and foodgrain stores. Recent studies have indicated that
pesticides like Indiara with a composition of diallyl disulphide, isothiocyanate, allylpropyl
disulphide is non-toxic and non-poisonous. Also, neem oil, castor oil and ginger paste
used as repellants and which are easily available in a catering facility, are recommended
as replacements for the more toxic insecticides.

With this, we end our study on pesticides and their use in food operations. Next, let
us move on to study about hygienic food handling.

18.7 HYGIENIC FOOD HANDLING

You would recall reading about food handling and storage in Units 6 and 7 earlier in
this course. Here we shall first have a look at the general rules for hygienic storage
and handling followed by specific rules/considerations for variety of foods.

Let us first consider a few rules regarding hygienic storage and handling.

General Rules for Hygienic Storage and Handling

1) There should be clean place for storage of cleaned and sanitized ware. Store all
items either on clean dry shelves or in cart racks. Dusty or dirty shelves will
quickly resoil cleaned and sanitized items.
2) Handle items as little as possible, taking care not to touch food or mouth contact
surfaces.
3) Storage area must be dry and above the floor. Splashes from mopping solutions
or food spillage, exposure to dust or floor dirt from sweeping must be avoided.
4) Pans or containers stored on low shelves should be placed inverted or covered.
5) Utensils etc. should be hung in a self-draining position on hooks or racks.
6) Glasses and cups should be inverted on racks or on shelves.
7) Silverware should be placed in perforated plastic containers to dry. Cutlery should
be picked up by the handle.
Despite careful selection, storage of food, and good personal hygiene on the part of
the food handler, outbreaks of food-borne illness can occur if unsafe procedures are
followed in preparing and mixing food and if temperature is not controlled during
preparing and holding food.

Sanitary procedures are very important during preparation, cooking and holding of
food because of the following reasons:
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Entrepreneurship and Food 1) Even if wholesome food is selected, microorganisms are still present in and on
Service Management food.
2) Not all food items served on the menu are cooked, for examples, salads.
3) Normal cooking procedures destroy most pathogens but not necessarily spores or
toxins.
4) Heating foods to safe temperatures is not always feasible as some foods may spoil
at high temperatures, for examples hollandaise sauce.
5) Food can get decontaminated during preparation, mixing or holding.
6) The internal temperature of cooked foods may not reach the safe temperature
level.
7) During preparation, food may get contaminated by other poisonous or harmful
substances.
Some bacteria are likely to be present and will multiply rapidly when ingredients are
mixed and their basic needs of (a) moisture, (b) nutrients, (c) temperature and (d) time
are met.
In the kitchen, most pre-reparations provide microorganism with sufficient moisture
and nutrients. The temperature in a hot, steamy, poorly ventilated kitchen is around
35°C the ideal temperature for microorganism to grow. If food is kept at this temperature
long enough, microorganisms will multiply and spoil food. Once spoilage occurs, if
cannot be rectified by freezing or pressure-cooking.
The majority of causes of food poisoning reported each year is caused by inadequate
refrigeration of perishable food. In India climatic conditions, perishable foods left at
room temperature for even three hours is at great risk as the ambient temperature is
higher as compared to western countries. It is necessary to follow the time-temperature
principles, especially when preparing perishable food. The food handler must observe
two basic rules when food is to be held:
1) Keep food hot, [at an internal temperature above 63°C (145°F)]
or
2) Keep food cold [ at an internal temperature below 5°C (41°F)]
During preparation, food should be exposed for a minimum possible time to temperatures
between 50°C to 63°C. This is the danger zone. Some common procedures in
preparation of food, which affect the microbial count, are highlighted herewith.

18.7.1 Procedures in Food Preparation which Affect the Microbial

Count
The procedure to be followed will depend to a large extent on the food being prepared.
Some common procedures, which affect the microbial count, are as follows:
1) Cleaning: Cereals and pulses are picked before they are milled or cooked, to
remove grit, mud, stones, husk, mouldy and insect-infested grains. Green leaves
are separated from the inedible roots and tough stalks.
2) Washing: Most foods need to be washed before preparation with potable cold
water. Washing removes extraneous matter like surface dirt, soil and preservative
and pesticide residue.
Fruits and vegetables to be consumed raw should be washed in a solution of
50 ppm chlorine for five minutes or in a dilute solution of potassium permanganate.
Leafy and salad vegetables should be washed thoroughly.
In case of suspected insect or worm infestation, soak fresh vegetables like
cauliflower in cold salted water for twenty minutes. If insects are present they will
rise to the surface.
442 Wash the body cavity of poultry well. Let all washed items drain well.
3) Pre-preparation: This step includes peeling, trimming and soaking. Potable water Issues in Food Safety
must be used for pre-preparation and cooking. Fruits and vegetables need to be
peeled, trimmed and cut to remove inedible or spoilt parts. Grains are soaked for
sprouting. Potable water should be used for all pre-preparation. No food container
should be placed on the floor as the floor is heavily contaminated. Keep all food
on racks or shelves.
4) Thawing: Frozen foods should be thawed completely before cooking, unless the
manufactures instructions are otherwise. Thawing large portions of food joints and
poultry takes time. Freezing only prevents bacteria from multiplying it does not
kill them. When a food is thawed, these dormant microorganisms start
multiplying rapidly once again.
If food is cooked while it is partially or totally frozen, a large amount of heat will have
to travel to the center of the food to melt the ice. The food may get cooked on the
surface, but internal temperature will not high enough to kill bacteria. The food is thus
likely to reach a temperature within the danger zone, which is favourable for bacterial
growth.

Meat may be thawed in a special thawing cabinet at a temperature of 10 to 15°C.

The advantage of such a cabinet is that cross-contamination is prevented and thawing
is faster and safer at a cool temperature of 15°C. A refrigerator may be used instead
of a thawing cabinet. Care should be taken to prevent any liquid from raw meat
dripping in the refrigerator and contaminating other foods. Raw meat can contaminate
any and everything it comes in contact with in the kitchen, like hands, work table,
chopping board, meat block, knives, cutters, utensils, dish cloth and dusters. These
articles can further contaminate other foods.

Never thaw meat by immersion in warm water or near heat as the microorganism on
the surface will grow rapidly while the center is still defrosting. Thawed meat should
be cooked immediately or kept in the refrigerator for maximum 24 hours before
cooking. Never refreeze meat, which has once thawed. If it has to be refrozen, then
cook and freeze. There are certain rules that must be considered for thawing food.
Let us see what these see.

Rules for Thawing Food

Thaw or defrost food in any one of the following ways:
1) In the refrigerator below 4°C (39°F).
2) In a thawing cabinet at temperatures between 10 - 15°C.
3) In potable running water at 21°C or below while it is still in the packet.
4) In a microwave oven, only when it has to be cooked immediately.
5) As per of conventional cooking, for example, certain frozen foods like frozen
vegetable and ready-to-eat chicken preparation are cooked in the frozen state
and quickly thaw when they are cooked.
Let us next review the different types of cooking methods and the microbial
contamination.

18.7.2 Cooked Food and Microbial Contamination

Food may be served uncooked, rare or medium cooked or well-cooked depending on
the foodstuff and the recipe. Cooking reduces the number of bacteria present in food.
The food handler should realize that conventional cooking procedures do not kill all
bacteria and spores or inactivate them. Hence, even cooked food should be handled
very carefully.

Food is a poor conductor of heat and for large pieces; longer time is needed for heat
to reach the center of the food being cooked. Generally, there are more bacteria on
443
Entrepreneurship and Food the surface than inside the food, unless it has been mashed, minced or rolled. In such
Service Management foods, bacteria present on the surface get distributed throughout the food. It is
necessary for the center of the food to reach temperature of at least 700°C for few
minutes while it is being cooked. Internal temperature can be checked with the help
of a probe thermometer. Wipe the probe with a sanitizing solution or isopropyl alcohol
after every use.

Most harmful bacteria present on the surface of a food are destroyed when food is
cooked. The microbial contamination in some common cooked preparations is
enumerated herewith.

Stuffed Preparation: While cooking any stuffed preparation, like stuffed chicken or
turkey, it is advisable to cook the stuffing and then stuff the bird. This is because
stuffing slows down heat penetration and sometimes even if the bird is cooked, the
temperature in the center may not be high enough to kill bacteria.
Food poisoning is more likely to occur from stuffed foods because:
1) Bare hands may be used to stuff the food.
2) Heat transfer is slow, permitting bacteria to remain in the danger zone for a
longer time.
3) Adequate heat may never reach the center of the food while externally the food
may be cooked to the desirable stage.
Although a final temperature of 63°C (145°F) is considered sufficient to prevent
microbial growth, the following temperature chart as given in Table 18.7 is recommended
for various meats.
Table 18.7: Ideal cooking temperatures for various meats
S.No. Food Stuff Internal
°C °F
1. Rare roast beef 54 130
2. Pork and pork products 66 150
3. Stuffed meat 74 165
4. Pork (gray stage) 77 170

The larvae of trichinella are killed at 66°C (150°F). As a precaution, it is recommended

that pork be cooked to the gray stage. It is preferable to cook or reheat food to at
least 74°F provided culinary quality is not lost.

Coated Preparations: Many food items are coated with a protective covering before
they are fried. This coating helps in retaining the juices and flavour of food and keeps
excess fat out. They are usually coated with batter or dipped in egg and covered with
breadcrumbs before they are cooked. These coverings act as good heat insulators and
reduce the transfer of heat to the food being cooked. They may also add to the
bacterial population. This can happen in conditions when:
1) the better is mixed by hand,
2) food is repeatedly dipped in better by hand,
3) microorganism from the raw food may contaminate batter,
4) if batter is state, and
5) dry bread crumbs favour microbial growth when they are moistened with beaten
egg and are left unused at room temperature. Excess batter or breadcrumbs should
be discarded or refrigerated.

444
Mixing Raw and Cooked ingredients: When raw and cooked ingredients are mixed Issues in Food Safety
and the products is not refrigerated or consumed immediately, it can lead to food
poisoning. Special care should be taken while preparing salads and sandwiches, which
are made from highly perishable foods like egg, meat and poultry. They should be
stored at refrigeration temperatures immediately. In sandwiches, the bread acts as a
heat insulator and prevents the filling from cooling fast. Preparing trifles, sandwiches,
etc. a day prior to use should be avoided.

Eggs may be contaminated with Salmonella which are destroyed only at 60°C (150°F).
This temperature may not be reached while preparing meringues, soufflés, egg nag,
soft cooked eggs and scrambled eggs. In such cases, use clean, whole shell eggs instead
of dried or liquid eggs.

We have in our discussion above highlighted the cooking methods and how they
influence the microbial growth. Once the food is cooked it is held at hot cold,
temperatures before serving. Also sometimes the left over food left in hot-holding
equipment during the entire lunch break is exposed to additional contamination. This
also influences microbial growth. Let us study about this aspect in greater details.

Holding Food: Food, after being prepared, need not necessarily be served immediately.
It may be held for sometime and then served. The holding can be for both cold and
hot foods. Extra precaution is needed while handling and storing such foods, as they
are prone to microbial attack. What are these precautions? Let us read and find out.

Precautions for Holding Hot Food

To maintain high culinary quality, food be prepared when it is needed and served as
soon as it is prepared. But this situation is not feasible in most catering establishments
as the volume of production is enormous and volume of sales cannot be accurately
predicted. To serve hundreds of lunches in a two-hour lunch break, calls for preparing
most of the items on the menu in advance. Foods which have to be served over an
extended lunch hour can be held hot with the help of a bain marie, double boiler steam
table or chaffing dish, The food handler should understand that these gadgets are not
reheating food but only hot-holding of foods. If used for reheating, food will remain
in the danger zone for a longer time.

The temperature at which food remains in the hot-holding equipment is very important
and should not be less than 63°C. If this temperature is not maintained, it is likely
that food spoilage will occur rapidly. Before keeping food in any of these equipments,
it should be heated to 74°C (165°F) and transferred immediately.
The following precautions should be taken during hot holding of foods:
1) Keep food covered to prevent heat loss.
2) Check temperature with a thermometer and not by just touching it with hand.
3) Stir occasionally for even heating as lower surfaces get heated and upper surfaces
get cooled by air.
4) use proper serving equipment like long-handled ladles and scoops to minimize
hand contact. Keep in a clean place when not in use.
5) Prepare and keep only required amounts as extended heating will affect flavour
and quality.
6) Dry preparations like chappatis, fried items and baked items may dry further, or
get overcooked during hot holding.
Cooling Food: Any perishable food, which is not to be consumed immediately, should
be kept outside the danger zone. Cold preparations like desserts should be cooled as
soon as possible to 15°C and stored in the refrigerator. Food should not be refrigerated
445
Entrepreneurship and Food while it is still hot, otherwise the maximum internal temperature in the refrigerator of
Service Management 4°C would increase and favour spoilage of other foods stored in the refrigerator. Food
must be cooled prior to refrigeration in the coolest part of the kitchen. Large columns
cool faster when divided into smaller portions or when kept in shallow containers.
Cooling can be hastened by keeping food containers in ice-cold water or in quick- chill
units. Food cools faster when the container is placed in water, as water is a better
conductor of heat than air.

Stirring food occasionally brings about a uniform drop in temperature and faster
cooling. Other factors which influence the cooling process are
1) the type of food,
2) the temperature in the refrigerator or quick-chill unit, and
3) the container used- size of container, material it is made of and covering, if any.
Cooked food, which is not to be consumed immediately, should be refrigerated with
1½ hour at 4°C or below. If refrigerator space is inadequate, it is wise to purchase
a quick-chill unit or extra bain maries for ice chilling. Large catering units should have
walk-in chillers for rapid cooling of cooked food.
Leftover food: All food items have to be stored till they are consumed.
Left food or surplus food includes all items that have been:
1) displayed but not during meal time,
2) items prepared but not used in function, and
3) items produced in more than required quantities.
Leftover food, which has not been served and is left in hot-holding equipment during
the entire lunch break, is exposed to additional contamination. Leftovers, which are
highly perishable in nature and have been in the danger zone for more than two to
four hours (depending on the nature of the food), should not be served. Most foods
can be kept for a day if they are not handled much and are stored at the correct
temperature and reheated adequately. Foods, which are usually contaminated with
spore, like Bacillus cereus in rice and Clostridium in meat, require proper reheating.
These foods are responsible for a number of cases of food poisoning. Conventional
cooking practices do not destroy spores and as food is cooked and enters the danger
zone, these spores germinate and bacteria begin to multiply and continues to do so
till food is refrigerated or reheated. They remain dormant in the regulator and when
food is reheated and passed through the danger zone, they multiply once again.

To control bacterial growth in leftover foods, the caterer should keep leftover to a
minimum and highly perishable or high-risk foods should not be reheated more than
once. With each reheating, the bacterial population increases. Surplus food should be
reheated thoroughly to destroy all vegetative bacterial cells. Just warming up a dish
before service would be doing it more harm than good, as bacterial growth would be
favoured.

Food prepared too far in advance can cause embarrassment to the caterer, who may
be tempted to use rather throw it away. It may be recalled that such food is one of
the main cause of food poisoning. Careful planning can minimize over production.

To prevent surplus food causing food poisoning, the following points should be noted:
1) All food prepared but not should be stored at or below 5°C.
2) The caterer should judge the quality of leftover food and then decide whether it
is to be used or not.

446
3) It is considered fit for consumption if it has not been handled excessively or Issues in Food Safety
exposed to high temperatures for long periods.
4) Surplus cold food should be returned to the chilled storage at or below 5°C until
required.
5) Surplus hot food must be cooled as quickly as possible and retriggered below 5°C
until it is to be reheated for service. It should then be heated to 74°C and kept
at a temperature above 63°C until it is served. It should be reheated only once.
6) Surplus hot food like roast joints which have been held at or below 5°C can be
served as cold food over the next two days, provided they are held at 5°C until
required for service.
7) Leftover food should be handled carefully to avoid contamination through dirty
knives, chopping board, equipment etc.
8) It should not be mixed with fresh food.
9) It should be carefully covered and stored away from fresh and war foods to avoid
possible risk of cross-contamination.
10) All excess food should be sorted into categories and refrigerated as soon as
possible and stored accordingly.

The management should look into the amount of overproduction and keep it to a bare
minimum. If large quantities of leftovers are present, the food should be cooled,
covered and labeled before returning the food to the refrigeration. The label should
also record the date before which the food should be used. Such cases arise only when
a function is cancelled or very few people turn up for a function because of bad
weather, etc.

When deciding whether or not to use leftover food, always remember –‘ if in doubt,
throw it out’.
Now let us see what should be the storage temperature so as to minimize microbial
spoilage
Storage Temperature of Prepared Foods: Food Safety and Standard Authority of
India have introduced hygienic and safe transportation, handling and storage temperature
of prepared food. If the prepared food is to be served in the near vicinity, it should
be transported and serve hot at temperature above 60°C and consumed within 4
hours. Otherwise, it should be chilled to less than 5°C and reheated to a temperature
of atleast 70°C which should be served at 60°C and consumed within 4 hours. On
the other hand, cooked food which is to be served cold should be kept at below 5°C
to prevent microbial growth.

Though chilling helps in extending the shelf life of food products, it can be effective
only when high standards of hygiene are observed. Caterers should check temperatures
on receiving deliveries. All allowances at 20°C in the temperature is given for up to
two hours for the following:
1) Defrosting of equipment.
2) Breakdown of refrigeration equipment.
3) During cold food preparation in the kitchen.
4) When food is moved around on the premises.
However, an exemption for certain foods from temperature control is permissible.
These foods/dishes include:
447
Entrepreneurship and Food 1) Certain foods are processed in such a way that it prevents the growth of
Service Management pathogens, for examples, sterilized canned food. Canned foods, which have been
only pasteurized, should be refrigerated and this should be indicated on the label.
2) Sandwiches with perishable fillings can be held at 8°C or below for a period of
24 hours only.
3) Mawa or khoa should always be refrigerated and used within 24 hours.
In our discussion so far we have reviewed the cooking methods and how they
influence the microbial growth. Further, we discussed the appropriate holding and
storage temperature of prepared and leftover foods which any individual/caterer in a
food service operation must follow. We would explore further and study about the
preparation methods for certain foods which are highly perishable and may require
careful handling.

Preparation of Specific Foods

In this section we will look at the preparation method of meat, fish fresh, fruits and
vegetables. These foods bring highly perishable require careful handling. Let us find
out.
a) Meat: Meat is a highly perishable food and gets contaminated from various
sources by the time it reaches the kitchen. It should be washed and trimmed as
it is cooked. Separate knives, cleavers and chopping boards should be used for
raw and cooked meat to reduce chances of cross-contamination.
Bacteria from raw meat may remain on improperly washed equipment and if the
same equipment is used for cutting ready-to-eat meat, like cold cuts which are
eaten without further cooking, the chances of food poisoning occurring become
very high. The bacteria on the raw meat are likely to get destroyed once meat
is cooked. After handling raw meat, wash hands well before touching cooked meat
or any other ready-to-eat foods which are not going to be heated again.
In the butchery, work table surfaces should be made of impervious material which
is easy to clean. The chopping block can be made of hardwood and should be
light enough to be removed for cleaning, scraping and rinsing after every use.
While deboning meat and making rolled joints, chances of contamination increase.
Such joints should be cut into small portions and cooked well to kill microorganisms
that may be present in the center of the cut.
Minced meat is at a higher risk than meat because microorganisms present on the
outer surface of meat get distributed throughout the entire mass of mince. Minced
meat is also handled more and spoil much faster, leading to discolouration and
foul odours and may cause food-borne illnesses. To reduce the chances of
spoilages, the following precautions should be taken:
1) Mince the quality required for the day only.
2) Cook mince thoroughly at sufficiently high temperatures.
3) Surplus mince be cooled rapidly in small portions.
4) Refrigerate surplus immediately.
5) Reheat mince thoroughly before serving.
6) If root vegetables like potatoes, carrots or onions are cooked along with
mince, clean them thoroughly to remove heat-resistant soil organism.
b) Fish: The best way to prepare fish is to place a stone slab long enough to fit
across the sink used for fish preparation and about two-third the width of the sink.
Place a hard wood board on it for cutting fish. This arrangement allows a
continuous flow of clean water with the wash going down the drain of the sink.
c) Fresh Fruit and Vegetables: Vegetables should be thoroughly washed to remove
448 traces of soil. If necessary, root vegetables may have to be soaked for sometimes
 and scrubbed clean as soil may contain Clostridium perfringens and Escherichia Issues in Food Safety
coil along with other intestinal pathogens. Some vegetables, like carrots and
ginger, may be scraped; fruits should be washed well and peeled, if required
before they are served. Peelings help in reducing microbial load and preservative
pesticide residue if any.
Green leafy vegetables should be washed under running water. Lettuce should be
broken up and washed. Leaves should be drained well. A separate sink should
be allotted for vegetables and fruit preparation. Spoilt, inedible portions be removed.
When food is handled carelessly, it is likely to get contaminated or spoilt and may
result in food poisoning. Box 18.2 highlights some common faults in food preparation.
Box 18.2 Common Faults in Food Preparation
The 10 most common faults responsible for outbreaks of food poisoning are:
1) Food prepared much before serving time.
2) Storing perishable food at room temperature beyond four hours.
3) Slow cooling of food in the kitchen at room temperature before refrigerating it.
4) Inadequate storage facilities and reheating of leftover food.
5) Cooking frozen meat or poultry without thawing it completely.
6) Cross-contamination from war to cooked food and use of cooked food
contaminated with bacteria
7) Undercooking meat and poultry.
8) Holding hot food below 63°C during service.
9. Infected food handlers.
10. Surplus food production and use of leftovers without checking quality.

With this we end our study of hygienic food handling. Next, we shall review the
personnel hygiene and sanitary practices linked with food safety in the next unit.

Check Your Progress Exercise 2

1) What are pesticides? How are they classified?
................................................................................................................
................................................................................................................
2) List some common rules that a food service worker needs to adopt for
hygienic storage and handling.
................................................................................................................
................................................................................................................
3) Give some examples of microbial contamination in some common cooked
preparations.
................................................................................................................
................................................................................................................

18.8 LET US SUM UP

Unit 18 focused on food safety. We learnt that microorganisms such as viruses,
bacteria, yeasts, moulds, algae and protozoa affect humans and their food. The food
handler should understand the importance of keeping food free from disease causing
organisms and other harmful agents. The safety of foods must always be considered
while storing, preparing and serving foods. The food handler should know that some 449
Entrepreneurship and Food microorganisms are useful to us and affect the basic characteristics of food producers.
Service Management Others are harmful and can cause spoilage of food and disease.
Food spoilage refers to decomposition or decay by microbes, animal parasites, natural
enzymes, physical or chemical changes, as well as, external contaminants. In this
context we learnt that spoilt food should always be discarded. Food that is decayed
is easier to recognize than foods spoilt by microorganisms or unobvious contaminants.
Foods have been categorized as perishable, semi perishable and non-perishable on the
basis of the ease with which they spoil. They need to be stored properly.
The other aspect covered in this unit was the importance of pest control. The presence
of pests and their body parts or droppings in food served will not only result in
contamination and spread in disease but can ruin the reputation of any catering
establishment.

18.9 ANSWERS TO CHECK YOUR PROGRESS

EXERCISES
Check Your Progress Exercise 1
1) The food handler can transmits pathogens to food directly because of coughing
or sneezing on or near the food, droplets containing microorganisms may fall on
the food. Further, unwashed or improperly washed hands transfer diseases of the
intestinal tract. If hands soiled with faecal matter handle food, disease-causing
agents are transferred to the prepared food. Consumption of such food causes
illness. When food is openly displayed, the customer handling the food can
contaminate it.
2) The important factors, which have an influence on growth, are food and nutrients,
pH level, moisture, temperature, oxygen, time and osmotic pressure and sunlight
or UV rays.
3) Refer to Table 18.4 and answer on your own.
4) a) True
b) True
c) False
d) True
5) Food poisoning is an illness caused by toxins present in contaminated food. The
toxin may be a poisonous chemical toxin, which is accidentally or intentionally,
added a naturally occurring poison like solanine in green potatoes or a toxic
metabolite excreted by bacteria. Food infection, on the other hand, is an illness
caused by microorganisms. It results from the consumption of food that contains
living bacteria, which are multiplying and capable of producing disease. The
illness, which results, is the reaction of the body to the presence of microorganisms
or to their metabolites.
Check Your Progress Exercise 2
1) Pesticides are substances, which have certain pharmacological effects on insects
and rodents, either as poisons or as repellants. Pesticides include insecticides
and rodenticides. Look up sub-section 18.6.1 and present the classification of
pesticides on your own.
2) Refer to section 18.7 and list the rules that a food service worker needs to adopt
for hygienic storage and handling.
3) Eggs may be contaminated with Salmonella which are destroyed only at 60°C
(150°F). Pork can be contaminated with larvae of trichinella. Similarly give some
more examples based on your understanding of the topic.
450