One of the golden rules of food safety is temperature control through the use of a thermometer.
It is essential that you regularly calibrate your thermometer to ensure that the readings are accurate and reliable.
Generally you will be able to check the accuracy yourself by using the following methods.
Cold temperature test
Obtain a mixture of 50 percent crushed ice (the ice obtained from the side of a chest freezer when defrosting it is ideal) and 50 percent cold water.
Transfer this into a suitable container, such as a glass or cup and let stand for a minute or two.
Place the probe of the thermometer into the mixture; do not let it touch the bottom of the container.
Wait for the temperature to stabilise, and then write the temperature onto the appropriate record sheet from your Food Safety Program.
The temperature should be between -1.0 degree C and 1.0 degree C. If the temperature is outside this range then conduct another test, if the result is still outside the specified range then either try replacing the batteries or purchase a new thermometer.
Discard inaccurate thermometers.
Hot temperature test
Place a saucepan of water onto the stove and bring the water to a rolling boil.
Place the probe of the thermometer into the water; do not let it touch the bottom of the saucepan.
Wait for the temperature to stabilise, and then write the temperature onto the appropriate record sheet from your Food Safety Program.
The temperature should be between 99.0 degree C and 101.0 degree C. If the temperature is outside this range then conduct another test, if the result is still outside the specified range then either try replacing the batteries or purchase a new thermometer.
Discard inaccurate thermometers.