Foodborne Illness and Allergens
Illness types and causes
Foodborne illness can be infection (live pathogen), intoxication (toxin), or toxico-infection (toxin produced in the gut). Common causes: improper cooling, inadequate cooking, cross-contamination, poor personal hygiene, and unsafe sourcing. Symptoms vary: nausea, vomiting, diarrhea, fever, abdominal cramps. Onset time can hint at cause: Staphylococcus aureus 1–6 hours; Bacillus cereus 1–6 hours (vomiting) or 6–24 hours (diarrhea); Salmonella 6–72 hours; E. coli O157:H7 2–10 days; Listeria 3–70 days.
Allergens
In Canada, priority allergens include peanut, tree nuts, sesame, soy, wheat, egg, milk, fish, shellfish, mustard, and sulphites. Allergen reactions can be severe (anaphylaxis). Controls: identify allergens in recipes, prevent cross-contact, clean and sanitize shared equipment, label clearly, and train staff. There is no cure; avoidance is the only protection.
Traps in questions
- Confusing cross-contamination (microbes) with cross-contact (allergens).
- Assuming removing an allergen from the top of a dish is enough: residues and shared utensils matter.
- Mixing up onset times: rapid onset suggests pre-formed toxin; longer onset suggests infection.
- Forgetting that sulphites are a priority allergen in Canada.
Worked example
A customer with a peanut allergy orders a dessert. The kitchen uses the same scoop for peanut-containing and plain ice cream. Correct action: use a dedicated scoop, wash hands and tools, and prepare the allergen-free order first or in a separate area.
Rule of thumb
When in doubt about an allergen, do not serve the food; offer a safe alternative and document the conversation.