Microbes and food 1. Menu - you are what you eat
Chicken preparation photo
Picture 1.2a You should use a separate board for preparing raw meat - especially chicken. This is to prevent cross-contamination.

1.2 Chicken
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What is it?
Chicken is usually bought raw and cooked in the home. However, many processed poultry products are also available from the chiller cabinets of shops. Raw chicken is sold either frozen or chilled. A wide variety of microbes can be present in both cooked and raw chicken.
How does it spoil?
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Raw chicken
Raw chicken becomes contaminated with bacteria from the gut, skin and feet of the birds during slaughter and from the water and ice used in processing. Chilling the carcass immediately after slaughter reduces the number of microbes on most meats because it dries the surfaces. However this has less effect on chickens because their skin can stay moist. The raw chicken is stored at a low temperature which reduces the rate at which bacteria reproduce. Eventually cold-loving microbes such as Pseudomonas will cause spoilage, making the meat smelly and slimy. Other factors which affect the rate of spoilage are pH and the type of packaging.

Cooked chicken
In the home chicken should be cooked thoroughly, handled hygienically, wrapped to prevent contamination by microbes from the air or other foods, cooled quickly and stored at 0–5°C. Refrigeration will slow the growth of microbes but it will eventually spoil. Cooked chicken should be eaten up quickly.

Cooked chicken photo
Picture 1.2b Cooked chicken.

The microbiological content of cooked poultry products depends on the methods of processing, packaging and storage. Sometimes bacteria and spores in the centre of the product may survive cooking. The meat may become contaminated after cooking during handling, slicing and packaging. Cured products will tend to spoil in the same way as other cured meats such as ham. Non-cured products which have been packaged in the absence of oxygen may be spoiled by Enterobacteria which produce very strong and unpleasant odours in the packet. Packaged meats should be consumed before the use–by date on the label.
Can it be harmful?
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Poultry is a common source of food-borne illness. Food poisoning bacteria such as Campylobacter jejuni, Salmonella, Clostridium perfringens and Staphylococcus aureus live in the gut and/or skin of the birds. They can get on to raw chicken during slaughter and processing. Outbreaks of food poisoning are often due to inadequate cooking or recontamination of the poultry after cooking. Raw poultry can also be a source of food poisoning bacteria for cross-contamination to other foods prepared in the same kitchen.
Chicken in a fridge photo
Picture 1.2c Raw chicken should be stored in the fridge on a low shelf away from cooked foods.


How should you store it?

Salmonella and Campylobacter account for most of the cases of food poisoning associated with chicken. A large percentage of raw poultry is infected with these bacteria, which is why it is so important to store, prepare and cook the meat properly. Raw chicken should always be wrapped – to prevent cross-contamination of pathogens to other foods – and kept in a refrigerator at 0–5°C to slow down microbial growth. It should be placed on the bottom shelf so that juices cannot drip on to other foods. Any knives, chopping boards and other utensils used to prepare raw chicken should be washed immediately after use in hot, soapy water.