Check the temperature with a thermometer

Why have a thermometer?

A thermometer is essential in ensuring that food is kept at safe temperatures. If your food business prepares, handles or sells any potentially hazardous food, it must have a thermometer which is accurate to ±1°C. The thermometer must be available for use when foods are being prepared, so you may need more than one if foods are prepared in different places.

How to clean and sanitise your thermometer

As the probe of the thermometer will be inserted into food, the probe must be cleaned and sanitised before it is used to measure the temperature of the food. This is especially important when the thermometer is used to measure the temperature of raw food and then ready-to-eat food, for example raw chicken and cooked chicken. To clean and sanitise your thermometer:

• wash the probe to remove any grease and food particles;
• sanitise the probe using alcohol wipes or very hot water; and
• thoroughly dry the probe using a disposable towel or let it air dry.

  Checking the temperature of food

• Determine the warmest area of a cool room or the coldest area of a hot display unit.
• Insert the clean, dry probe into the food.
• Remember that temperature readings are not instant- wait until the temperature has stabilised before reading.
• Stabilise the thermometer between measuring hot and cold foods by allowing the thermometer to come back to room temperature.
• If the food is packaged or frozen, place the length of the probe between two packages of the food.

Remember that the temperature at the centre of food may be different from the surface temperature. For example, when cooked food is being cooled in the refrigerator, the centre of the food will take the longest to cool. Therefore, when checking the temperature of this food, make sure that you check the centre.

How to check the accuracy of your thermometer

Thermometers must be accurate to ensure that temperatures are correctly measured. Ask the company that supplied your thermometer how often the thermometer should be checked for accuracy. It is best to have your thermometer regularly checked and maintained by the supplier of the thermometer. However, if you would like to check the accuracy of your thermometer yourself, use the following method.

• Place some ice into a container with a small amount of cold water. The ice should not float if the correct amount of water is used.
• Mix into a slurry and insert the thermometer probe.
• Leave it for about three minutes.
• Check and note the temperature. It should read 0°C.
• Do this three times and compare the temperatures recorded.
• If they vary by more than 1°C, get your thermometer checked by the supplier.