Contamination occurs when something not normally found in the food is added. Contamination implies the addition is not intended or planned. The substance added may or may not cause problems. Three main sources of contamination are from physical, chemical, and microbial sources.

Physical Contaminants Physical contaminants are substances that become part of a food mixture. They may not change or damage the food itself. However, their presence can create health hazards for the consumer. For instance, metal filings or broken pieces of glass have occasionally gotten into foods. These materials would not spoil food, but they could cause injury if swallowed.

Chemical Contaminants Keeping insects and other pests under control can lead to chemical contamination. Insecticides are chemicals used to improve crop yields by reducing losses due to insects. Herbicides are used for the same reasons to control weeds. Both types of substances are pesticides. If pesticide residues remain on food, they enter the food supply.

Correct food handling practice and food storage helps prevent bacteria from contaminating and multiplying on foods. The following action needs to be taken to prevent bacterial contamination:

• Protect food from contamination – handle food properly
• Prevent bacteria from multiplying
• Destroy germs on/in food

Fig. 3.33: The food contamination chain can be broken in several places.

Food can be protected from contamination by handling it with care. Food handlers should think about:

• where food poisoning bacteria come from. They can come from people's bodies, sneezes, coughs, high risk foods, insects, rodents, pets, toilets and dust particles in the air
• the different ways bacteria can get on to the food they are handling, for example, from cross contamination and contaminated hands and clothing
• the correct cooking and storage temperatures which prevent bacteria multiplying

The number of people affected in an outbreak of food poisoning will depend on where the food contamination occurs. For example, contaminated food prepared and eaten in the home is only likely to affect a few people but contaminated food prepared in a fast food outlet or in a factory is likely to affect many people.



 

1 Correct food handling rules

Always wash hands with soap and warm water before handling food. Wet the hands before applying the soap. Make sure you rub in between fingers and on the front and backs of hands. Remember to clean under fingernails. Rubbing with soap loosens bacteria. They must be rinsed off with water. (When possible, use hot water for washing the hands.)
 

Fig. 3.33: The food contamination chain can be broken in several places.

Food can be protected from contamination by handling it with care. Food handlers should think about:

• where food poisoning bacteria come from. They can come from people's bodies, sneezes, coughs, high risk foods, insects, rodents, pets, toilets and dust particles in the air
• the different ways bacteria can get on to the food they are handling, for example, from cross contamination and contaminated hands and clothing
• the correct cooking and storage temperatures which prevent bacteria multiplying

The number of people affected in an outbreak of food poisoning will depend on where the food contamination occurs. For example, contaminated food prepared and eaten in the home is only likely to affect a few people but contaminated food prepared in a fast food outlet or in a factory is likely to affect many people.



 

1 Correct food handling rules

Always wash hands with soap and warm water before handling food. Wet the hands before applying the soap. Make sure you rub in between fingers and on the front and backs of hands. Remember to clean under fingernails. Rubbing with soap loosens bacteria. They must be rinsed off with water. (When possible, use hot water for washing the hands.)

Fig. 3.34: Wash hands before handling food and be sure to clean under the finger nails.
Always wash hands with soap and warm water after going to the toilet or touching any parts of the body, such as the skin or nose.

Fig. 3.35: Wash hands after going to the toilet.

• Do not smoke while preparing food
• Handle food with tongs, a spoon or some other utensil which is clean
• When sneezing or coughing always cover the face with a tissue or the hands and turn away from the food. Wash hands immediately after as they may have been contaminated
• Avoid preparing food for others if you have diarrhoea

Fig. 3.36: If sneezing, turn away from the food and use a tissue.
 

• If food does have to be left standing in the open for a few minutes during preparation always cover it with a lid, clean cloth or cling wrap
• Do not let raw high risk foods touch other foods
• Always clean and sanitise utensils and benches/work surfaces used to prepare high risk foods immediately after the food has been prepared
• Work benches and cooking utensils should always be kept clean
• Make sure insects, rats, mice and other pests cannot get into the food preparation area
• Pets should also be discouraged from domestic kitchens and must never be allowed into a shop or community kitchen

Fig. 3.37: Keep all work benches clean.

• Dispose of rubbish regularly and correctly
• Make sure the floors, walls, window sills and all fixtures in the food preparation area are regularly and properly cleaned

2 Correct food storage

Food