Section 11.16 All Areas: Temperature Checking of Foods
The purpose of this section is to ensure product checked for temperature, using the recommended infrared equipment is done so in a correct manner according to manufacturer’s guidelines.
Detailed Instructions
Surface Temperature Checks
Surface temperature checks may be performed using the infrared thermometer. This unit has an accuracy of +/- 1.00C when used correctly and when mindful of its limitations.
When used in low room temperatures between 0 and 5oC we have noted accuracy is reduced to +/- 2oC.
The unit is pointed directly at a food or food contact surface approximately 10 -15cm from the surface.
The trigger is pressed for a minimum 1 second to a count of 3. NO LONGER.
The temperature of the food will display for approximately 10 seconds. Record each check on the relevant check sheet.
Do not test:
- Reflective surfaces such as metals, stainless steel, thick plastics/glass due to infra-red sensitivity.
- Non-food contact surfaces (i.e. food packaging that has no physical contact with the food eg pizza boxes)
- OR food types of high air content (e.g. pies, pastries, frozen peas/frozen food bags where there is air between the packaging and the food)
- OR packaging materials designed to insulate such as cardboard or tetra pack boxes, foam packs, thick plastic tubs (e.g. ice cream) , aluminium (as above), black coloured packaging where possible, or and,
- At distances too far or too close by pointing the Raytec less than or more than 6 inches away from the food. Note : Too close to frozen foods can fog up the temperature sensor very quickly.
- On surface for long periods as surrounding temperature affects repetitive accuracy (NB: not laser)
- Inside freezer rooms or below 0oC as the lens freezes up re-moisture droplets and is rendered unusable. Will recover when allowed to sit for minimum of 15 minutes in ambient (room) temp.
Core Temperature Checks
Insertion into the product is the MOST ACCURATE RESULT POSSIBLE!!
All core temperature checks are performed using a calibrated probe thermometer with an accuracy of no less than +/- 0.50C as this procedure may be used to validate surface temperature results and is potentially a destructive test for packaged foods.
The probe portion of the thermometer is checked to ensure it is clean and dry prior to use. It is then inserted into the food so that the end 40-50 mm of the probe is approximately in the thickest part, or the core, of the food.
[DO NOT SIT Probe between bags of food as this probe is not sufficient to determine an accurate reading this way. However, if you need to perform a non-destructive test, then you need to minimise exposure to the probe by fully covering every millimetre of the probe as best as possible. If incorrectly done, readings will not be true.]
The probe portion is to sit in the food for at least 3 minutes to allow the temperature to stabilise. The food must be kept in adequate storage during this period, i.e. the Bay Marie for hot foods, a freezer for ice creams, or a refrigerator for perishables.
NOTE: Do not attempt to place the probe into frozen food as this may cause probe bending and damage to testing device.
Record each check on the relevant check sheet and remove the probe.
Carefully remove the probe from the thermometer unit and wash it with soapy water and sanitise.