Hazard analysis depends on knowing every kind of hazard that could make food unsafe. There are four types: biological, chemical, physical and allergenic.

As a manager, you need to recognise each type, understand how it gets into food or grows there, and know how it can be controlled.

In this module you will learn about:

• Bacteria, and the conditions they need to grow.
• Spores, toxins, viruses, parasites and moulds.
• Chemical hazards.
• Physical hazards.
• Allergenic hazards.
• Cross-contamination.

Biological hazards are the most common cause of food poisoning. The most important are harmful bacteria, such as Salmonella, Campylobacter, E. coli O157, Listeria, Clostridium perfringens, Bacillus cereus and Staphylococcus aureus.

Bacteria need food, moisture, warmth and time to grow. Most grow fastest between 5 and 63°C, the temperature danger zone. In ideal conditions, their numbers can double every 10 to 20 minutes.

• Spores: some bacteria, such as Clostridium perfringens and Bacillus cereus, form spores that survive cooking and germinate as food cools. Fast cooling is essential.
• Toxins: some bacteria produce poisons that are not destroyed by reheating.
• Viruses: norovirus and hepatitis A are spread mainly by infected food handlers and contaminated shellfish. They do not grow in food, but very few are needed to cause illness.
• Parasites, such as worms in fish, and moulds, which can produce harmful toxins, are also biological hazards.

Chemical hazards include:

• Cleaning chemicals and sanitisers, if they are stored or used wrongly.
• Pest control products.
• Machinery lubricants, and chemicals that migrate from unsuitable packaging.
• Natural toxins, such as those in poisonous mushrooms, some fish and red kidney beans that are not properly cooked.
• Residues of pesticides and veterinary medicines.

They are controlled by approved suppliers, safe storage away from food, correct use and clear labelling.

Physical hazards are foreign objects in food, such as glass, metal, hard plastic, wood, stones, bone, hair, jewellery, pest bodies and packaging. Their sources can be remembered as the six Ps: people, premises, plant, packaging, pests and product.

They can cause cuts, choking and broken teeth. They are controlled by:

• Good personal hygiene, and rules on jewellery and hair.
• Equipment maintenance, and glass and hard plastic policies.
• Careful unpacking of deliveries.
• In manufacturing, sieves, magnets, metal detectors and X-ray machines.

Fourteen allergens must be declared by law: celery, cereals containing gluten, crustaceans, eggs, fish, lupin, milk, molluscs, mustard, tree nuts, peanuts, sesame, soya, and sulphur dioxide and sulphites.

For an allergic customer, even a trace can cause a severe reaction that may be fatal.

Allergen information must be provided for all food. For food that is not pre-packed, it must be available in writing.

Cross-contamination is the transfer of a hazard from one place to another, usually from raw food to ready-to-eat food. It can happen:

• Directly, for example raw meat dripping onto cooked food in the fridge.
• Indirectly, through hands, chopping boards, knives, cloths and equipment.
• Through allergens, for example using the same oil or utensils for different dishes.

It is controlled by separation of raw and ready-to-eat food, colour-coded equipment, cleaning and disinfection, and hand washing.