Physical, chemical and allergenic contamination

Contamination means anything in food that should not be there. Bacteria and viruses, known as microbiological contamination, cause most food poisoning, and the next lessons cover them. Three other types also cause harm.

Physical contamination means an object in food. Common examples are hair, plasters, glass, staples, packaging, jewellery and dead insects. Some objects come with the food, such as bones or small stones in dried pulses. They can choke someone, break a tooth or cut the mouth.

To prevent this, take food out of outer boxes before it goes into the kitchen. Keep hair covered and jewellery off. Report cracked or broken equipment. If glass breaks near open food, stop work and tell your supervisor. Throw away all the food the glass could have reached. Do not try to pick the pieces out.

Many physical hazards come from everyday habits. Staples and string fall from boxes opened over food. Pen tops and badges fall from pockets. Flaking paint and loose screws fall from shelves and equipment. If something is worn or loose, report it before it ends up in food.

Chemical contamination means a harmful chemical gets into food. Examples are cleaning products, pest bait and machine oil. Store chemicals away from food, in their original labelled containers. Never put a chemical in a food container or a drinks bottle. Never spray near open food, and use the amount the label tells you to. Use only packaging and containers marked as suitable for food contact.

Allergenic contamination means an allergen gets into food that should not contain it. This is often called cross-contact. Cooking does not remove allergens, so a tiny amount of flour or nuts can still be dangerous after the food is heated. A later lesson covers allergens in detail.