Food is dangerous when it contains something that can harm whoever eats it. There are four kinds of hazard:
- Biological: bacteria (such as Salmonella or Listeria), viruses (such as hepatitis A) and parasites (such as Anisakis in fish).
- Chemical: traces of cleaning or disinfecting products, insecticides or any toxic substance that ends up in food by mistake.
- Physical: glass, bits of plastic or metal, staples, hair, stones.
- Allergens: for someone with an allergy, a trace of peanut or prawn is as dangerous as a bacterium (module 6).
How people get ill
AESAN describes three routes: infection (eating the live microorganism, as in salmonellosis or hepatitis A), intoxication (eating the toxin it has already produced, as in botulism or staphylococcal toxin) and parasitic disease (such as trichinellosis or anisakiasis).
Microorganisms multiply when they have nutrients, moisture, a suitable temperature and time. That is why almost every rule in this course aims at one of three things: stopping them reaching the food, stopping them multiplying (cold and little time) or killing them (heat).
Looks are not enough. Heavily contaminated food can look, smell and taste fine.
Source: AESAN, «Preventing food poisoning» (WHO golden rules, in Spanish) · Regulation (EC) No 852/2004 on the hygiene of foodstuffs (consolidated text), Annex II, Chapter IX, points 1 to 3 · Spanish Royal Decree 1021/2022, hygiene in retail, bars and restaurants (consolidated text, in Spanish), Article 9