PHYSICAL AND
CHEMICAL HAZARD
Chemical hazards
■ The contamination of food by chemical hazards is a worldwide public health concern
and is a leading cause of trade problems internationally. Contamination may occur
through environmental pollution of the air, water, and soil, such as the case with toxic
metals, polychlorinated biphenyls (PCBs) and dioxins, or through the intentional use
of various chemicals, such as pesticides, animal drugs, and other agrochemicals.
■ Chemical hazard in food include chemical compounds that, when a sufficient amount
is consumed, can inhibit absorption and/or destroy nutrients. These hazards are
carcinogenic, mutagenic, and teratogenic. Their toxicity can cause severe illnesses
and possibly death because of their toxological effect on the human body.
■ Chemical hazards are usually classified as either naturally occurring chemicals or
added chemicals.
■ Naturally occurring chemicals include toxins produced by a biological organism.
■ Added chemicals include those that are intentionally and unintentionally added to
food.
Common Chemical Hazards in Food
Retail Operations (Food Code, 2000)
Naturally Occurring Chemicals Added Chemicals
• Ciguatoxin • Cleaning solutions
• Mycotoxin • Food additives
• Scombrotoxin • Pesticides
• Shellfish toxins • Heavy Metals
Ciguatoxin
■ DESCRIPTION: A fish-poisoning intoxication from the consumption of tropical fish.
The origin of the toxin is from minute creatures called algae. The toxin is heat stable
and cannot be destroyed by cooking. Symptoms: common foodborne illnesses
symptoms and unique symptoms including weakness and sight paralysis of the
mouth, tongue, throat, hands, and feet.
■ COMMON FOOD: marine finfish (barracudas, groupers, jacks, mackerel, snappers,
and triggerfish.
■ TRANSMISSION IN FOOD: after ingestion of toxin-containing algae
■ PREVENTION: purchasing from a reputable supplier is the best preventive measure
Scombrotoxin
■ DESCRIPTION: it is also called histamine poisoning caused by eating foods in high
chemical compound called histamine. Histamine which usually produced by bacteria
when they decompose foods. It is not destroyed by cooking. Unique symptoms:
dizziness, a burning sensation, facial rash or hives, and a peppery taste in the
mouth.
■ COMMON FOOD: tuna and mahi-mahi fish, Swiss cheese has also been implicated
■ TRANSMISSION IN FOOD: overtime, bacteria present in a particular food can break
down histidine in food and cause the production of histamine. Temperature abuse
also leads to more histamine production.
■ PREVENTION: purchase of food from a reputable supplier. Store seafood below 47℉
and do not accept seafood that has been previously thawed.
Shellfish Toxin
■ Description: there are numerous examples of shellfish toxins. The most common
include paralytic shellfish poisoning (PSP). Diarrheic shellfish poisoning (DSP),
amnesic shellfish poisoning (ASP), and neurotoxic shellfish poisoning (NSP). All
involve an accumulation of toxins produced in shellfish.
■ Common food: PSP is more common in mussels, clams, and scallops. DSP can be
caused by mussels, oysters, and scallops. ASP is more common in mussels while
NSP is common in Gulf Coast marine animals.
■ Transmission in Food: Shellfish toxins are inherent in marine shellfish.
■ Prevention: purchase food from a reputable supplier
Mycotoxins
■ Another group of foodborne microorganisms that can cause disease include fungi.
Fungi include both molds and yeasts. They differ from bacteria in that they are larger
in size and usually prefer foods that are high in sugar or starch. Often they can
withstand more extreme conditions.
■ Foodborne molds can produce chemical compounds called mycotoxins which have
been linked to cancer.
Added Chemicals
■ Intentionally added chemicals include food additives, food preservatives and
pesticides. Pesticides leave residues on fruits and vegetables, and can usually be
removed by a vigorous washing procedure by peeling off the produce skin.
■ Chemical hazards can be divided into three general categories: poisonous
substances, adverse food reaction (food allergy sensitivity), and nutrition issues.
Poisonous Substances
■ Toxic Plant material includes solanine in potatoes; hemagglutinins and protease
inhibitors in raw beans and peas; cyanogens in fruit kernels; and phytoalexins in
sweet potatoes, celery, and parsnips.
Chemical Associated Food
Oxalates rhubarb Tea, cocoa, spinach, and beef
Glycoalkaloids Green potato
Cyanoglycosides Lima beans and cassava
Phytohaemagglutinin Red kidney beans and other beans
Various carcinogens Spices and herbs
Poisonous Substances cont’d…
■ Intentional food additives include GRAS (generally recognized as safe) compounds
that may have inadvertently been added in excessive amounts.
■ Examples: excessive addition of nitrites and nitrates in processed meat
– Excessive use of sulfites in dried fruits and wine
– Intentional addition of undisclosed ingredient
Anti-caking agents Flavor enhancers Oxidizing and reducing agents
Antimicrobial agents Flavoring agents pH control agents
Antioxidants Humectants Propellants and gases
Colors Leavening Agents Sequestrants
Curing and pickling agents Release agents Solvents and vehicles
Emulsifiers Non-nutritive sweeteners Stabilizers and thickeners
Enzymes Nutrient Supplement Surface-active agents
Firming agents Nutritive Sweeteners Texturizers
Poisonous Substances cont’d…
■ Chemicals created by the process include those created when meat is broiled
excessively over hot charcoal and when fat or oil has been heated excessively or for
a long time. Some contaminants produced include polynuclear aromatic
hydrocarbons, heterocyclic amines, nitropyrenes, nitrosamines, ethyl carbamate
(urethane), and chloropropanols.
■ Agricultural Chemicals include pesticides and herbicides.
■ Animal antibiotics and other drug residues are also a problem in terms of foodborne
illness hazards. Drug residues in food can cause violent allergic reactions in
sensitive people who consume these products.
■ Unintentional Additives or accidental addition of toxic substances during food
handling in the food service and food production operations can also occur.
■ Equipment material such as copper or lead from pipes or soldering material, can
likewise leach into food and water causing heavy metal poisoning.
Poisonous Substances cont’d…
■ Package material can leach as well. In the US, there were concern about leaching of
lead from the solder of can seams and polychlorinated biphenyls from cardboard
packages. Since then, these compound has been almost completely eliminated from
packaging systems. However, these types of packaging material may still exist in the
other parts of the world. There is also concern over the safety of certain plastics,
especially those that may be used in the heating or reheating foods in a microwave
oven.
■ Heavy metals and radioactive isotopes from industries can also find their way into
food, usually through water sources. E.g; the level of mercury in fish taken from
lakes and rivers
