A thermometer is an essential HACCP tool in any central kitchen or large super markets. Kitchen staff should have thermometers to check temperatures periodically for several jobs inside the kitchen, to ensure that jobs are done according to hygienic standards and to check accuracy of permanent installed thermometers, the following are some examples of required temperature measures;
Checking of received refrigerated or frozen food in receiving area.
Checking of stored food temperatures in cold store & freezer room.
Checking of minced meat temperature.
Checking of cooked food temperature during serving, before inserting into a blast chiller, after transportation, etc.
Checking of frying oil temperatures.
Checking of dishwasher sanitizing water temperature
Digital thermometers have several shapes & temperature ranges according to type of food. Fig.17.7.1 shows hand held thermometer with its probe directly connected to the thermometer.
Fig.17.7.1 Pocket hand held thermometers – ETI– UK
Fig.17.7.2 shows hand held thermometer with remote wired probe for easy reading of display. Fig.17.7.3 shows Infrared thermometer which is also called “Non contact thermometer” or “Non destructive thermometer”, this type of thermometer can remotely measure food temperature without penetrating or touching food, this type is useful for measuring of frozen food with or without packing (penetrating frozen food pack will damage it), also for salads & fruits, meat slices, fish slices, etc.
Fig.17.7.2 Hand held thermometer with remote wired probe – ETI– UK
Fig.17.7.3 Non contact infrared thermometer – ETI– UK
- Materials; heavy duty plastic casing, stainless steel probe.
- Should be approved by any international independent authority for measuring food temperature and preferred to have calibration certificate.
- Type of thermometer (see above).
- Temperature unit; °C and/or °F.
- Temperature range in °C or °F (according to required job, see example).
- Should have clear, large enough display.
- IP protection degree, to ensure that water, dust or dirts can not flow to inside thermometer (see Basics for more information about IP).
- With or without hold function (i.e. to keep measured temperature without change until checking carefully, recording, checking by some body else, etc.).
- Accuracy in ± °C (indicates maximum error thermometer reading, lower value is better, usually between ± 0.1°C to ± 1°C, see example).
- Sensitivity in °C (the smallest value thermometer can sense and display, e.g. 0.1 °C sensitivity means that thermometer can read temperatures with 0.1°C steps such as 7.2 – 7.3 – 7.4 °C, but it can not read less than 0.1°C – for example 7.35 °C).
- Should work efficiently in local ambient temperature with no reading errors.
- Probe is preferred to be of penetrating type – Fig.17.7.4 – to facilitate measuring internal temperature of some foods (e.g. received or displayed fresh meats, fish, etc)
Fig.17.7.4 Penetrating type probe – ETI– UK
- Penetrating tool may also be employed for hard food penetration such as frozen foods (if internal temperature is required).
- With or without memory (to store previous readings).
- With or without printing facility.
- Battery life in hours.
- With or without automatic switch off (if not used for certain period, e.g. 10 minutes).
- With or without color coding (to avoid cross contamination results from using of same thermometer for different types of food without sanitizing).
- See next example.
As shown in Fig.17.7.2, a Hand held thermometer with the following features; remote wired probe, IP 66/67 waterproof proof protection, temperature range (-39.9 to 149.9°C), accuracy of ± 0.4°C over range (-10 to 70°C) /, 0.1 °C resolution, 15 mm LCD display, with °C or °F display, ABS plastic with Biomaster anti-bacterial additive, 5 years life battery, 220 grams weight, dims 32 x 71 x 141 mm, model (Therma 20 Plus), manufactured by “Electronic Temperature Instruments Ltd – ETI” – UK. thermometer.co.uk