The four types of contamination

Contamination means something in food that should not be there. There are four main types. Each one can make food unsafe.

Microbiological contamination is caused by tiny living things such as bacteria and viruses. They can be on raw food, hands, cloths, bins and surfaces. They are the main cause of food poisoning.

Physical contamination means an object in food. Examples are hair, a plaster, a piece of glass, a staple from a box or a bit of packaging.

Chemical contamination means a harmful chemical gets into food. Examples are cleaning spray on a salad, or pest bait near open food.

Allergenic contamination means an allergen gets into food that should not contain it. For example, nuts from one dish fall into another. A tiny amount can cause a serious reaction.

In a low-risk role, simple habits stop most of this. Keep food covered. Keep chemicals away from food. Keep your work area tidy. Carry clean plates and cutlery on a clean tray, and hold them by the edges or handles, not by the part that touches food.

If something looks, smells or feels wrong, stop and report it to your supervisor. Do not use it, and do not quietly throw it away. The same problem may affect other food. For example, if you find a broken jar next to an open box of bread rolls, there may be glass on the rolls. Keep the box aside and tell your supervisor.