Limits, monitoring and corrective action

Temperature control is more than a number on a wall chart. It is a system. For each step where temperature matters, the system must answer five questions. What is the limit? Who checks it? How and how often is it checked? What happens if it fails? Where is it recorded?

List the steps that matter in your business: delivery, chilled and frozen storage, cooking, cooling, reheating, hot holding, display and transport. For each step, set a limit from the law, your guidance pack or your hazard analysis. Many businesses also set a target that is tighter than the limit. If a fridge has a target of 5°C or below, a reading of 6°C is a warning. You still have time to act before food reaches 8°C.

Decide who monitors. Name a role, and name a deputy for days off. Decide how often. A fridge may be checked at the start and end of each day. A large joint may be probed every time it is cooked. A well-tested method for a small product may need a check on only some batches, if your system shows that this is safe. SFBB calls this 'prove it'.

Understand what you are measuring. A fridge display usually shows air temperature, which changes quickly when the door opens. Food temperature changes more slowly. Do not take a reading straight after a delivery, when the door has been open for a long time or during a defrost cycle. Check the warmest part of the unit. To check food, use a clean probe, or place the probe between two packs so that you do not pierce the packaging.

Corrective action has three parts. First, deal with the food. Decide if it is safe, and then move it, finish cooking it or throw it away. Second, deal with the cause. Close the door, call the engineer or change the rota. Third, record what happened and what you did. The job is not finished until all three are done.

Here is an example. The morning check at a café in England finds a fridge at 11°C. The check the evening before showed 4°C. Nobody knows how long the food has been above 8°C. Because the time is unknown, the supervisor throws away the high-risk food. She moves the rest of the food to a working fridge, calls the engineer and records it all. If she cannot show that food stayed safe, she must not serve it.

Review the records. A supervisor should read them regularly, sign them and ask questions. Look for gaps, repeated borderline readings, and failures with no corrective action. Data loggers and wireless sensors can help, because they record all the time and can send alarms. But an alarm is only useful if someone is responsible for acting on it at night and at weekends.