Updating guides…
Covers bacterial contamination, high-risk foods, the temperature danger zone, safe storage and cross-contamination.
Harmful bacteria that cause food poisoning, such as Salmonella, Campylobacter, E. coli and Listeria, multiply fastest in warm, moist conditions with a food source, doubling in number roughly every 10 to 20 minutes under ideal conditions. The temperature range in which bacteria multiply most rapidly is called the danger zone, between 5°C and 63°C. This is why food should not be left at room temperature for long periods, and why hot food should be kept above 63°C and cold food below 5°C wherever possible.
High-risk foods are those that provide ideal conditions for bacterial growth, typically foods high in protein and moisture that are ready to eat without further cooking, such as cooked meat and poultry, dairy products, cooked rice, shellfish and eggs. To be considered safe, high-risk food should be cooked until it reaches a core temperature of at least 75°C, which can be checked using a probe thermometer. Fridges should be kept below 5°C (ideally between 1°C and 4°C) and freezers at -18°C, to slow or stop bacterial growth.
Cross-contamination is the transfer of harmful bacteria from one food, surface, or piece of equipment to another. This commonly happens when raw meat touches ready-to-eat food, or when the same chopping board or knife is used for both without washing in between. To prevent this, separate chopping boards and utensils should be used for raw and ready-to-eat foods (often colour-coded, for example red for raw meat), and raw meat should always be stored at the bottom of the fridge, covered, to stop juices dripping onto other foods.
Food should be stored according to its label instructions, with raw and cooked foods kept separately and covered. The 'use by' date shows the date after which a food is unsafe to eat even if it looks and smells fine, while a 'best before' date relates more to quality than safety. Frozen food should be defrosted safely in the fridge overnight, never left out at room temperature, as this allows the outer layer to reach the danger zone while the centre is still frozen, encouraging bacterial growth.
Good personal hygiene reduces the risk of contaminating food, including washing hands thoroughly before handling food and after touching raw meat, tying back long hair, wearing clean protective clothing, covering cuts, and avoiding food preparation when unwell. Common symptoms of food poisoning include nausea, vomiting, diarrhoea, stomach cramps and fever, usually appearing within hours to a few days of eating contaminated food.