The Four Types of Food Contamination

Biological contamination

This is contamination by living things — bacteria, viruses, moulds and parasites. It is the most common cause of food poisoning and the focus of most food-safety rules.

Biological hazards spread from raw foods, dirty hands, pests and contaminated water. You control them mainly through hygiene, separation of raw and ready-to-eat foods, and temperature control.

Chemical contamination

Chemicals get into food from cleaning products, sanitisers, pest sprays, or substances leaching from unsuitable containers. Even small amounts can cause illness, and some are highly toxic.

• Store chemicals well away from, and never above, food
• Never decant chemicals into unlabelled drink bottles or food containers
• Rinse and air-dry surfaces where required after sanitising
• Only use food-grade containers for storing food

Physical contamination

Physical contamination is a foreign object in food — something a customer could choke on, break a tooth on or be cut by. Common sources include glass, metal, hard plastic, bandages, hair, fingernails, jewellery and packaging.

Prevent it by keeping the kitchen tidy, tying back hair, removing jewellery, using coloured bandages, and checking that nothing has fallen into food during prep.

Allergenic contamination

An allergen is a normal food ingredient (such as peanut or milk) that is harmless to most people but can trigger a severe, even fatal, reaction in someone with an allergy. When an allergen gets into a dish that is supposed to be free of it, that is allergenic cross-contact. Allergens are covered in detail in a later module.