FOOD SAFETY HAZARDS :

Biological Hazards

Department of Food Science and Technology

Faculty of Agricultural Technology
Bogor Agricultural University
2009
 Biological Hazard

Biological hazards consist of microscopic living

organisms that grow or persist in food and cause
illness in humanbeings :
• Bacteria
• Viruses
• Protozoa
• Parasites

Dept Food Sci and Tech, Bogor Agricultural University, Indonesia

 Characteristics of Biological Hazards :

• Able to grow during post harvest, receiving,

handling, packaging, storage_ may double the
number within 20 minutes
• May produce toxins and excrete it to the
(environment or food)_thus cause intoxication
without their presence
• Can be reduced and/or inactivated by
processing (heating, freezing, irradiation etc)

Dept Food Sci and Tech, Bogor Agricultural University, Indonesia

 BACTERIA

Type Examples Characteristics Modes Food implicated

Bacteria, Salmonella heat sensitive, dry underprocessing, raw and
vegetative resistant, cause post process pasteurized milk,
infection, mostly contamination egg,
not invasive, watermelon,
except for S, typhi peanut butter,

Enterohemorrhagic heat sensitive, underprocessing, hamburger, pool

Escherichia coli withstand post process water, apple
(EHEC)/STEC freezing and low contamination cider,RTE
pH spinach

Listeria heat sensitive, underprocessing, coleslaw, cheese

monocytogenes tolerate and grow post process from
at refrigeration contamination unpasteurized
temperature, followed by milk, RTE
abundant in stoirage at processed meat
environment refrigeration

Dept Food Sci and Tech, Bogor Agricultural University, Indonesia

 BACTERIA
Type Examples Characteristics Modes Food implicated
Bacteria, Staphylococcus aureus Heat sensitive, poor post process picnic set up, ham
vegetative, toxin competitor produce contamination of sandiwich, cream-
producer heat stable RTE in abused time filled-bakery,
enterotoxins temperature storage pasteurized milk
Bacteria, Burkholderia heat sensitive, contaminate and tempe bongkrek
vegetative, toxin cocovenenans produce heat stable grow during (fermented
producer neurotoxins bongkrek shredded coconut)
processing, and
handling
Bacteria, spore- Clostridium Heat stable, produce contaminate raw beef dishes, gravy
former, toxin perfringens diarrheal and emetic material, form
producer enterotoxins spores during
cooking, germinate
due to slow cooling
at room temp
Bacteria, spore- Clostridium botulinum Heat stable, produce contaminate raw Canned food, fish,
former, toxin heat labile material, form garlic in oil, baked
producer neurotoxins spores during potato in
cooking, germinate foil,hazelnut
during slow cooling topping on
, produce toxins in yoghurt,carrot juice
anaerobically and
pH>4.6

Dept Food Sci and Tech, Bogor Agricultural University, Indonesia

 VIRUSES

Type Characteristics Modes Examples Food

implicated

Viruses Grow in living Generally Hepatitis A (raw or

cells only, do fecal inadequately
not grow in contamination cooked)
food, heat of raw food or shellfish
sensitive human
contamination Rotavirus beef
of processed
food Norovirus salad, person-
to-person
(cruise ship)

Dept Food Sci and Tech, Bogor Agricultural University, Indonesia

 PROTOZOA AND PARASITES
Type Characteristics Modes Examples Food implicated

Protozoa Single cell The cysts persist Giardia lamblia water, food
animals, in environment handled with
intracellular and may contaminated
parasites, do not contaminate water
grow in food, food, grow and Cyclospora raw vegetables
sensitive to heat, multiply within
freezing human body

Worms Multicellular The cysts persist Ascaris water, soil, food

animals, in environment lumbricoides handled with
intracellular and may contaminated
parasites, carry contaminate water
out sexual food, grow and Taenia saginata beef
reproduction, do multiply within
not grow in food, human body Fasciola liver
sensitive to heat, hepatica
freezing

Dept Food Sci and Tech, Bogor Agricultural University, Indonesia

 Factor affecting Growth of Microorganisms

 Intrinsic factors
pH
Water activity (aw)
Nutrient
Antimicrobials
Biological structures

 Extrinsic :
temperature
humidity
gas (carbon dioxide, ozone, sulfur
dioxide)

Dept Food Sci and Tech, Bogor Agricultural University, Indonesia

 END OF LECTURE 2

Dept Food Sci and Tech, Bogor Agricultural University, Indonesia