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Unformatted text preview: PURCHASING AND RECEIVING FOODS Thermometers are important tools to use in each step of the food handling process to ensure that temperature abuse does not occur. Thermometers are delicate instruments that need to be tested routinely for accuracy. They can lose their accuracy when they are dropped, bumped, or when they are exposed to a severe temperature change. You can restore the accuracy of most bimetallic- stemmed thermometers by adjusting them, which is referred to as “calibration”. However, some thermometers cannot be calibrated, and instead must be replaced. Use thermometers to check the temperatures of incoming: • Shipments of food products, • Final cooking temperatures, • Cooking temperatures, • Food in refrigerators, freezers, and hot holding units. The most common type of thermometer used in food service is the bimetallic metal- stemmed thermometer, which measures temperature through a metal probe with a sensor in the end. This thermometer is calibrated to measure food temperatures ranging from 0 ° to 220 ° F (-18 ° to 104 ° C) without freezing or breaking. It is ideally suited to checking food temperatures during receiving and holding foods. Because of its long stem, it is also a good choice to measure large or thick foods. When using a bimetallic metal-stemmed thermometer, be sure that it is at least five inches long and easy to read. Also, be sure it has: • Easy to read, numbered temperature markings • An adjustable calibration nut to keep it accurate • Accuracy levels guaranteed to within +2 ° F (+1 ° C) • A dimple that marks the end of the sensing area, which begins at the tip • The metal stem of the thermometer must be inserted into the product being measured to the stems dimple mark, approximately 1-½ inches. Metal-stemmed digital thermometers are available in a variety of styles and sizes, from pocket models to panel-mounted digital displays. They use devices to measure temperature called “thermocouples” or “thermistors”. These devices measure temperatures using a metal probe or sensing area, and display the results in a digital readout. The sensing area is located on the tip of the probe, which means they don’t have to be inserted into foods as far as the bimetallic metal-stemmed thermometers. Thermocouple and thermistor thermometers are adequate for testing internal temperatures of firm foods such as beef roasts or whole turkey, as well as thin foods, such as hamburger patties. Various types of temperature probes are used for different applications: • Immersion probes, which are designed to measure the temperature of liquids, such as fryer oil. • Surface probes, designed to measure the temperature of flat cooking surfaces....
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- Spring '11
- Thermodynamics, food products, Thermometer