3.Biological hazards

Food poisoning

Food poisoning occurs when pathogenic bacteria contaminate food and are then allowed the opportunity to multiply sufficiently to overcome our natural defences and threaten our health. They are the biggest single threat to food safety. Getting rid of pathogenic bacteria from the environment completely is impossible, so preventing them from reaching food and / or multiplying is a key responsibility of all food handlers.

Groups most at risk from the effects of food poisoning include pregnant women, young children, the elderly and those with a chronic illness or reduced immunity.

Symptoms of food poisoning are unpleasant and often include vomiting and diarrhoea, but recovery in most cases only takes 1-3 days. However, food poisoning can also lead to serious medical problems with life changing or even life-threatening consequences.

Can all foods cause food poisoning?

Yes, but some foods are at higher risk from pathogenic bacteria than others.

High-risk foods
Foods categorised as high-risk include raw and cooked meats, dairy, seafood, and foods containing these as ingredients. Other high-risk food examples include gravy, sauces, stock, soup, pate and prawns. High-risk foods are high in protein and usually contain high moisture levels; conditions that pathogenic bacteria love.
Low-risk foods
Low-risk foods are those that generally speaking can be stored at ambient temperatures (ambient means without refrigeration). Dried foods such as pasta or rice are low-risk, until cooked - when water is introduced, the risk increases.
Key

Food poisoning only
occurs when corners are cut or mistakes made. Follow your approved food preparation processes, hand hygiene regime and your supervisor’s instructions

Point

How bacteria multiply

Pathogenic bacteria are dangerous microscopic bacteria capable of causing illness, common examples of pathogenic bacteria include Salmonella, E. coli and Clostridium. They enter food through contamination and can quickly multiply to dangerous levels.

When bacteria find themselves in the right conditions, they multiply by each cell dividing in two. Two cells become four, then four become eight and so on. Bacteria can divide in this way once every 10-15 minutes allowing them to multiply rapidly.

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ClickTap the circle to see how bacterial loads increase over time:

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Bacteria need 4 factors in place to multiply rapidly:

1. Food - Like us, bacteria need food, and especially protein, to survive and multiply. They thrive in raw and cooked meat, dairy, fish and seafood. They also thrive in ready-to-eat foods including filled sandwiches and any foods containing ingredients such as mayonnaise and pate.

2. Moisture - Bacteria need water to live. They cannot multiply in dried (dehydrated) foods, for example, dried pasta or rice, and powdered milk.

3. Warmth - Bacteria multiply rapidly between 8°C and 63°C. This is known as the danger zone. Understanding the threat of the danger zone is vitally important to food safety.

4. Time - Over time, if the above factors are present, bacteria will continue to multiply. In optimal conditions multiplication will happen very quickly.

What to do...

To prevent bacteria multiplying to a dangerous level we need to:

  • Minimise the time high-risk food spends in the Danger Zone
  • Chill and use high-risk foods according to the manufacturer’s instructions
  • Cook and reheat following your approved processes
  • Serve, cool and refrigerate, or hot hold food promptly
Key

Bacteria multiply
rapidly between
8°C and 63°C
This means that you should aim to cook and serve food almost immediately or put it
in the chiller or freezer to
keep it safe.

Point

Bacterial toxins

Many pathogenic bacteria release poisonous substances called toxins. Cooking kills most pathogenic bacteria but the toxins left behind can still cause illness. Toxins are one of the reasons why storage at the correct temperature is so important to food safety.

Spores

Several pathogenic bacteria are resistant to extreme temperatures; they achieve this by developing a protective shell known as a spore. When returned to optimal conditions, they start multiplying again. Rice is particularly susceptible to spore forming pathogenic bacteria.

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Key

No cooking, reheating or other process will make food safe once bacterial toxins are present. Therefore, you should keep raw and high-risk foods in the chiller and throw them away if in doubt.

Point

Pathogenic viruses

We are constantly exposed to pathogenic viruses. Some can be confused with food poisoning, due to similar symptoms, for example Norovirus. Sometimes a new pathogenic virus emerges from which we have no immunity to, for example, Coronavirus.

Pathogenic viruses spread from person to person through airborne particles produced when an infected person coughs or sneezes, and when contaminated hands touch and contaminate other surfaces and objects.

Pathogenic viruses

The key to defeating the threat of all pathogenic viruses is to break the chain of contamination. Appropriate distancing, hand hygiene, cleaning and disinfection, teamwork and early illness reporting are all key to defeating pathogenic viruses. Following the guidance outlined in this course and following your supervisor’s instructions will be crucial in defeating pathogenic viruses in your premises.

Pathogenic viruses

Viruses are spread through the air in droplets caused by sneezing and coughing, and through contaminated hands, objects and surfaces. Wash your hands regularly, report illness promptly, and sanitise surfaces following your approved cleaning schedule.

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Key

Wash your hands regularly, report illness promptly, and sanitise surfaces following your approved cleaning schedule.

Point
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Physical, chemical and allergenic hazards
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