How Does Food Get Contaminated : Steps in the Food Production Chain

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The Food Production Chain

It takes several steps to get food from farm to fork. We call these steps, “The food production chain”. Contamination can occur at any point along this chain. Production, processing, distribution and preparation. So how does food get contaminated? Let’s take a look at step in the chain so that we can identify where in each step contamination can occur.

Production

Production can be defined as, growing crops that are harvested or raising animals that are used for food. Most foods come from either domesticated stock animals and crops where production occurs on farms. Some foods are caught or harvested from the wild such as fish, mushrooms and game.

How does food get contaminated in the production chain?

• Chicken can get carry many different bacteria that is carried on the skin or in the gut. Chicken is known to eat their own and the flock’s faeces, which allows the bacteria to spread throughout. During the slaughtering process, incorrect washing of the chicken can cause the contamination to transfer to the meat.
• Infected udders of a cow can transfer to the milk, making unpasteurised milk products very high risk.
• A hen’s reproductive organs can get infected where the yolk of an egg then becomes contaminated in the hen even before the egg is laid.
• In the fields, the soil can harbour bacteria that is natural to the environment, but dangerous to humans. The use of animal manure can also be very dangerous.
• If the fields are sprayed with contaminated water for irrigation, fruits and vegetables can become contaminated before harvest.
• Fish in some tropical reefs may get a toxin from smaller sea creatures that they consume.
• These then transfer the contamination to us when we consume these foods.

Processing

Processing is defined as altering crops or animal meats into what we recognise as food. Processing can involve various steps using a variety of foods.

If contaminated water or ice is used to wash, pack or chill fruits or vegetables the contamination can spread to those items.

Peanut butter can become contaminated if roasted peanuts are stored in unclean conditions or come into contact with contaminated raw peanuts. This is a good example of cross-contamination of raw ingredients and the final product.

During the slaughtering process, pathogens on an animal’s hide can come into contact with intestines and can contaminate the final product. This is especially true for chickens.

How does food get contaminated in the Processing chain?

• If contaminated water or ice is used to wash, pack or chill fruits or vegetables the contamination can spread to those items.
• Peanut butter can become contaminated if roasted peanuts are stored in unclean conditions or come into contact with contaminated raw peanuts. This is a good example of cross-contamination of raw ingredients and the final product.
• During the slaughtering process, pathogens on an animal’s hide can come into contact with intestines and can contaminate the final product. This is especially true for chickens.

Distribution

Distribution is the means by which we transport food from farm to processing plants to the consumer or food service facility such a restaurants or hotel kitchens. This step may involve transporting foods just once, such as trucking produce from a farm to local farmers markets or it may involve many stages.

For example, frozen hamburger patties might be transported from a meat processing plant and then to a larger supplier, stored for a few days in the suppliers’ warehouse, trucked again to a local distribution facility for a restaurant chain and finally delivered to an individual restaurant.

How does food get contaminated in the distribution chain?

• Refrigerated food being left out on a loading dock for too long in warm weather. These could encourage temperatures of a critical range which allow bacteria to grow.
• Fresh produce can be contaminated if it is loaded into a truck that was not properly cleaned and sanitised after the transporting of animals or animal products.
• The contents of a glass jar that breaks in transport can also contaminate nearby foods.
• Chemical spillages can also contaminate products.

Preparation

Preparation can be defined as the process of getting foods ready-to-eat. This step may occur in the kitchen of a restaurant, home or catering facility. It may also involve following a complex recipe with many ingredients, simple heating and serving on a plate or just opening a package and eating the food.

How does food get contaminated in the Preparation chain?

• Not sufficiently washing fruits and vegetables.
• A food-handler coming to work whilst he or she is sick and spreading the illness to staff and customers.
• Staff not washing their hands after using the toilet or handling raw meat.
• If a chef uses a cutting board or knife to cut raw chicken and then uses the same knife or cutting board without washing, to slice tomatoes, this could cause possible cross-contamination from the chicken.
• Contamination could also occur within a refrigerator if meat juices get into contact with any other items.

Mishandling at multiple points

By the time food causes illness, it may have been mishandled in several ways along the production chain. Once the contamination occurs, further mishandling of food such as undercooking or leaving out at ambient temperatures can allow an outbreak to be more likely. Many pathogens grow quickly in food held at room temperature and a tiny amount can grow to a large number in just a few hours.

Reheating foods after items have been left out at room temperature for long periods, may not always be the final answer due to pathogens that produce toxins that are not destroyed by heat. Therefore, it is imperative to follow all the food safety pillars to ensure that a solid foundation of safe food can be built.