To prevent problems you have to know what can go wrong. This lesson goes through the hazards in food and how they spread from one thing to another.
Four kinds of hazard
- Microbiological hazards: bacteria, viruses and parasites. They cause most food poisoning.
- Chemical hazards: for example cleaning agents, pesticides and excessive levels of certain substances.
- Physical hazards: foreign objects, for example glass, plastic, metal, bone fragments, jewellery or plasters.
- Allergens: substances that can cause allergic reactions in sensitive people. They get a lesson of their own.
Some common disease-causing microorganisms
- Salmonella is found in, among other things, eggs, poultry and meat. It is killed by sufficient heating.
- Campylobacter is often present in raw poultry.
- EHEC/STEC (disease-causing E. coli) can be present in minced beef and lamb, because bacteria from the surface are mixed through the whole mince.
- Norovirus causes winter vomiting disease. The infection can be passed to food by a person who is ill or has just been ill.
- Listeria can grow even in the cold and is dangerous for pregnant women, older people and people with weakened immune systems.
- Bacillus cereus and Clostridium perfringens form spores. The spores survive heating. The bacteria can grow if food cools too slowly, for example a large pot left to cool.
What bacteria need to grow
Bacteria thrive where there are nutrients, moisture, time and the right temperature. Food that is rich in protein and moist, such as meat, fish, eggs, dairy products, cooked rice and cooked pasta, is particularly sensitive. That is why the main controls are temperature and time: cold goods are kept cold, hot goods are kept hot and food must not stand out longer than necessary. We go through temperatures in a lesson of their own.
Cross-contamination
Cross-contamination means that dirt, bacteria or allergens are transferred from one thing to another. It can happen through:
- hands that first touched raw meat and then salad
- utensils, chopping boards and knives used for both raw and ready-to-eat food
- surfaces that have not been cleaned between raw and ready-to-eat food
- liquid that runs from raw meat in the fridge down onto other food
- cloths and dishcloths that are used everywhere
- waste that ends up near food
How to prevent it:
- Keep raw and ready-to-eat apart, in time, in different places or with different utensils.
- Store raw meat and raw fish at the bottom of the fridge, in sealed containers, so that nothing can run down.
- Use separate chopping boards and knives or clean thoroughly between uses.
- Wash your hands after raw food. Change gloves.
- Store ready-to-eat food with ready-to-eat food and cover it.
- Rinse vegetables that will not be heated, and keep soil away from ready-to-eat goods.
Ready-to-eat food is extra important
Food that is eaten without heating, for example salad, sandwiches, sushi, cold cuts and desserts, has no step that kills bacteria. Anything that gets onto it stays there. Be extra careful with hygiene and temperature for these items.
Risk groups
Small children, older people, the sick and pregnant women are more susceptible to foodborne illness. This applies especially in nurseries, schools, health care and social care. The Swedish Food Agency also mentions that pregnant women should avoid pork, lamb and game that is not cooked through unless it has been frozen, because of the risk of toxoplasma.
Your role
You do not need to be an expert on bacteria. You need to know that food can become dangerous without looking, smelling or tasting odd, and that it is the procedures that protect the guests. Follow them and speak up if something does not work.