Keeping food at safe temperatures is one of the main ways we prevent food poisoning nowadays. Almost every business has something that needs to be kept in the fridge, so temperature checking is a daily activity for most. If you are reheating or cooking food, then there is even more checking to do. A surprising number of people get this all wrong.
Check food or water, not air.
When checking the temperature of chilled food, many people make the mistake of relying on the display temperature on the unit, either the digital display or old dials. Those only measure air temperature, and fluctuate wildly when you open and shut the door. However the food inside will not be changing temperature quite so fast, and its that temperature that we want to measure.
So check the temperature of water or food in the fridge. Don’t buy those metal dial thermometers you hang on the shelf, they are only indicating air temperature. Same with milk thermometers with dials, they are too inaccurate.
Use the right thermometer
To check chilled food temperature, you can either use an infrared thermometer (often called a laser thermometer) and hold it close to a food. Or you can use a digital probe thermometer. You need to put the probe into a something like a container of water that you leave in the fridge. Or you could use a lemon or other cheap food so you don’t poke holes in all your good stuff. If you like having a more constant display of the temperature that you can check all the time, the digital thermometers with a probe on a wire are good. But again you must suspend the probe into water. Don’t just leave it hanging in the air.
Checking cooked or cooling or hot food
If you need to measure cooking, cooling or hot holding temperatures, you’ll need a probe thermometer. Infrared only measure the surface temperature, so you cant tell how hot the inside of a pie is by checking the surface pastry, you need to probe the middle. Similar for cooking chicken, it’s the inside temperature we are worried about so you need a digital probe.
Clean your probe
If you use your probe in food like cooked pies, you need to clean it properly between uses. You can buy probe wipes, or spray some sanitizer spray onto a paper towel and clean the probe.
Calibrating your thermometer
Thermometers need to be calibrated every six months to check they are accurate. We know water boils at 100 degrees and ice forms at 0 degrees, so we can use this to calibrate our thermometers. You can download the free thermometer calibration instructions and record sheet for more guidance.
Where to buy thermometers
Specialist hospitality stores sell all types of thermometer, including the ones you don’t want. They also have fancy versions like infrared with a pull out probe. A regular digital probe is about $30 from places like cooking shops, brewing stores or bin inn type shops, or on the internet. Infrared thermometers can be bought from cooking shops, and even places like DIY centres and tool shops now, from around $60. Calibrate it when you first get it to ensure its accurate enough for food use.
Summary
If you can only afford one thermometer, get a digital probe that can be used for everything. And always check the food itself or some water, not just air.