Temperature rules by nation

Some temperature rules are the same everywhere and some are not. A supervisor must know which is which, especially when working across more than one nation.

Chilled storage. In England, Wales and Northern Ireland, food that can support the growth of pathogens must be kept at 8°C or below. This is a legal maximum. Aim for 5°C or below, so that you have a margin. In Scotland the law sets no fixed number. Such food must be kept in a refrigerator, a refrigerating chamber or a cool ventilated place. FSS recommends 5°C or below.

Hot holding. In England, Wales and Northern Ireland, hot food held for service must be kept at 63°C or above. In Scotland it must be kept above 63°C.

Display tolerances. England, Wales and Northern Ireland have two limited tolerances for food on display or for service. Each can be used once only for a batch of food. The business must be able to prove it stayed within the tolerance, so write the time on the tray or label.

Hot food may be kept below 63°C for a single period of less than 2 hours. After that it must not go back on display. The simplest rule is to throw it away. FSA guidance also allows it to be cooled as quickly as possible to 8°C or below.

Cold food may be kept above 8°C for a single period of less than 4 hours. Before the 4 hours end, either put it back in the fridge until it is used, or throw it away. It cannot go on display outside the fridge a second time. After 4 hours it must be thrown away.

Do not use these two tolerances in Scotland. The Scottish rules set no tolerance periods like these. There, control food on display through your HACCP-based procedures.

The law in England, Wales and Northern Ireland also allows for short, unavoidable breaks in chilling, such as loading a van, handling food during preparation, a defrost cycle or a temporary breakdown. The break must be limited and consistent with food safety, and the business must be able to prove this too.

Cooking. The FSA gives these equivalents at the core of the food: 75°C for 30 seconds, 80°C for 6 seconds or 70°C for 2 minutes. CookSafe in Scotland recommends 75°C or above, or a suitable lower temperature held for a suitable time. Poultry, pork, rolled joints, minced meat products and offal must be cooked all the way through. Whole cuts of beef and lamb can be served pink if the outside is properly sealed.

Reheating. This is where the difference is greatest. In England, Wales and Northern Ireland, food must be reheated until it is piping hot throughout, and a core of 75°C is the common guide. In Scotland the law requires at least 82°C, unless this would harm the quality of the food. CookSafe gives 70°C for 2 minutes as an example of an alternative for such food. In every nation, reheat food once only.

Cooling. Cool food as quickly as possible, ideally within 90 minutes. Do not put hot food in a fridge, as this warms everything around it. Divide food into smaller portions, use shallow trays, slice large joints, or use a blast chiller. CookSafe in Scotland sets no fixed time, but says to cool as quickly as possible and allows you to set your own time limit.

Freezing. Keep frozen food at −18°C or colder in every nation. Defrost food fully before cooking, unless the maker's instructions say to cook from frozen. The fridge is the best place to defrost.

Think again about a company with sites in Carlisle and Dumfries. A single rule to reheat to 75°C works in Carlisle, but it does not meet the law in Dumfries. The company must either write a separate rule for each site or use 82°C at both.