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Food safety

What is cross contamination | How to prevent cross contamination

What is cross contamination?

It is important to prevent cross contamination because foods like raw meat, shell eggs and unwashed vegetables can contain harmful bacteria. These raw foods can be made safe by cooking, as this kills the bacteria.

In the case of salad vegetables, bacteria can be removed by peeling, trimming and thorough washing. However, the harmful bacteria on these foods can spread to cooked or ready-to-eat foods either by direct contact or via people, animals and objects.

Safe handling practices will reduce the chance of transferring harmful bacteria from raw food to cooked or ready-to-eat food. This is known as cross contamination prevention.

The most common causes of cross contamination are:

• by direct cross contamination - contact between raw food and cooked or ready-to-eat food during transport, storage or preparation
• by indirect cross contamination - for example via equipment, splashing, chef's cloths or food handlers.

How to prevent cross contamination

• staff must have good personal hygiene
• do not use chefs cloths for wiping hands and then dishes
• thoroughly wash hands after handling raw foods and before touching other food or equipment
• use separate refrigerators for raw and cooked or ready-to-eat foods where possible. If not possible then store raw food in the bottom of a shared refrigerator and below the cooked or ready-to-eat foods
• raw meat must be stored separately from raw vegetables
• raw food which is being defrosted should be stored on the bottom shelf of the refrigerator in a tray or bowl that will catch any 'drip' as the food is defrosting
• store food containers off the floor to prevent them picking up dirt which could be transferred to the work surfaces
• separate designated equipment should be used for raw and cooked or ready-to-eat foods. If this is not possible then it must be thoroughly cleaned and disinfected between uses. Many business find that a colour coding system can help with this. They following colours are commonly used:
  • Red - raw meat or poultry
  • Blue - fish
  • Green - vegetables
  • White - diary
• all foods in the process of being cooled should be kept separate from raw foods
• designated utensils should be used for the handling of raw food and separate utensils for cooked or ready-to-eat foods
• it is important to reduce the handling of ready-to-eat food. This may be achieved in various ways such as the use of dedicated tongs and serving spoons. This will assist in reducing the risk of cross contamination
• when cleaning, it is recommended that high risk areas are cleaned before low risk areas, especially when the same equipment is being used
• you should also used separate cloths for cleaning raw areas from cooked or ready-to-eat areas. Remember that cleaning cloths can help to transport bacteria around your premises
• you may wish to document the cross contamination policy for you business.

Here is a template of an individual employee training record:

Employment training record (59kb) PDF

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