Food Safety Hazards and Foodborne Illness
Domain 1 tests how you classify hazards, explain microbial growth, and link pathogens to foods and controls. Expect questions that ask for the most likely cause of an outbreak or the control that matches a specific hazard.
Hazard categories
- Biological hazards-bacteria, viruses, parasites, fungi-cause most foodborne illness.
- Chemical hazards include cleaners, pesticides, allergens, and toxic metals.
- Physical hazards include glass, metal, bone, and packaging fragments.
What drives bacterial growth
FATTOM summarizes the conditions: Food, Acidity, Temperature, Time, Oxygen, and Moisture. TCS foods support rapid growth because they are moist, low-acid, and protein-rich. Keep them out of the temperature danger zone, 41°F to 135°F.
Pathogen patterns
- Spore-formers such as Bacillus cereus and Clostridium perfringens survive cooking; slow cooling lets them grow.
- Staphylococcus aureus and Bacillus cereus can produce toxins that cooking does not reliably destroy.
- Norovirus and hepatitis A spread through hands and ready-to-eat foods; they do not multiply in food.
- STEC and Salmonella are associated with raw animal foods and produce.
Worked example
A caterer cooks rice at 8 a.m., leaves it in a warm kitchen until 2 p.m., then reheats it. The likely hazard is Bacillus cereus: cooked rice is a TCS food, the holding period is in the danger zone, and reheating does not destroy the toxin. The control is rapid cooling or hot holding at 135°F or above.
Traps
Do not assume the last meal caused illness; incubation periods vary. Do not say cooking makes a toxin-contaminated food safe. Do not confuse viruses with bacteria that multiply in food.