Kitchen Thermometers

 Kitchen Thermometers

It is critical to use a food thermometer when cooking meat, poultry, and egg products to prevent uncooked foods. Verify that food reaches an adequate minimum internal temperature, thereby preventing foodborne illness.

Why should you use a food thermometer?
Using a food thermometer is the only reliable method for the consumer to ensure that meat, poultry, and egg products are well done. To be safe, these foods must be cooked to an adequate minimum internal temperature to destroy any harmful microorganisms that may be present in them.

- Kitchen Thermometers and Instant-Read Thermometers Product

"Well done" means that a food has been cooked to the desired point and exhibits the sensory appearance of the food in terms of texture, appearance and juiciness. These sensory aspects are subjective, unlike the cooking temperatures required so that the food is not harmful to health.

Color is not a reliable sign
Many people who work with food think that certain visible signs, such as color change, can be used to determine if food has been cooked to the point of eliminating pathogens. However, recent studies have shown that the color and texture are not to be trusted. For example, ground beef can turn brown before reaching the temperature at which pathogens are destroyed. The consumer who prepares hamburgers and is guided by the brown color as a sign that they are already "well cooked" runs the risk that pathogenic microorganisms have survived. In contrast, a hamburger that is cooked to an internal temperature of 160ºF (71.11ºC), when measured with a food thermometer, is properly cooked, whatever its color.

Safety versus Fully Cooked
The temperatures at which different pathogens are destroyed vary, as do the temperatures at which different meats and poultry are "ready." The consumer who is guided by visual color change to decide when meat is done may continue to cook until meat is overcooked and dry. However, the consumer who uses a food thermometer to check if the food is “ready” can be sure that their food has reached a suitable temperature and is not overcooked. Cooks all raw beef, pork, lamb, and veal roasts, steaks, and chops to a minimum internal temperature of 145 ˚F (62.8 ˚C), by measuring with a food thermometer before removing the meat from the oven. heat source. For safety and quality, allow a standing time of at least three minutes before mincing and consuming the meat. For reasons of personal preference, consumers may choose to cook meats to a higher temperature.

Cook ground beef, pork, lamb, and veal to a temperature of 160 ˚F (71.1 ˚C), as measured with a food thermometer. All birds should reach an adequate minimum internal temperature of 165ºF (73.9ºC).

Also use the food thermometer to ensure that cooked foods are kept at a suitable temperature until serving time - cold foods at 40ºF (4.4ºC) or less, and hot foods at 140ºF (6ºC) or more. .

Types of thermometers
Food thermometers come in many types and styles and vary in level of technological advancement and in price.

Digital food thermometers

Thermocouple or Thermocouple:
Of all food thermometers, thermocouples are the fastest to measure and indicate the final temperature, in 2 to 5 seconds. Temperature is read numerically on a digital display.

Point and press the button to enlarge the image. These thermometers measure the temperature at the connection point of two fine wires attached to the tip of the probe. Thermocouples used in scientific laboratories have very fine probes, similar to hypodermic needles, while others may have probes as thick as 1/16 of an inch.

Since these thermometers are very fast, the temperature can be quickly checked in various places to ensure that food has been cooked properly. This is especially useful when cooking large foods such as roasts or whole turkeys, where it is recommended to check the temperature in different places. The fine probes on these thermometers are also suitable for checking the temperature of thin foods such as ground beef patties, pork chops, and chicken breasts.

These thermometers can be calibrated for accuracy.

Thermistor:
Food thermometers of this type use a thermal resistance sensor (a ceramic semiconductor tip bonded with heat sensitive epoxy) to measure temperature.

Point and press the button to enlarge the image. The thickness of the probe is approximately 1/8 inch and it takes about 10 seconds to indicate the temperature on the digital display. Since the semiconductor is at the tip, thermometers with thermal resistance can record the temperature of thick or thin foods. Since the center of food is generally colder than its surface, place the tip of the thermometer in the center of the thickest part of the food.

These thermometers are not designed to remain in food while it cooks. They should be used a little before the end of the estimated cooking time to verify the final temperatures reached. To prevent food from overcooking, check the temperature towards the end of the estimated cook time.

Not all thermistors can be calibrated. Read the manufacturer's instructions.

Thermometer with cable for ovens:
These food thermometers allow the cook to check food temperatures without opening the oven door. The base unit, provided with a digital display, is connected to a probe, similar to that of thermistors, by a long electrical cable. The probe is inserted into the food and the cable runs from the oven to the base unit. The latter can be placed on the counter or it can be attached by a magnet on top of the stove or on the oven door. The thermometer is set to the desired temperature and emits an audible signal when that temperature is reached. Although these thermometers are designed for use in the oven, they can also be used to check the temperature of food being prepared on the stove. Corded oven thermometers cannot be calibrated.

Thermometer and Fork Combination

Point and press the button to enlarge the image.This utensil combines a kitchen fork with a food thermometer. A temperature sensor is embedded in one of the tines of the fork. There are different brands and styles of thermometer forks on the market; some use thermocouples and other thermistors. The temperature of the food is presented numerically on a digital display or by a lighted indicator on the handle, in 2 to 10 seconds, depending on the type. The lights will indicate if the food has reached a level of raw, medium or well done. Especially useful when grilling, the fork-thermometer accurately measures the internal temperature of food even when it is very thin. These forks are to be used to measure the temperature of food towards the end of the cook time and are not designed to remain on the food while it is cooking in the oven or on the grill. Thermometers of this type cannot be calibrated.

Circular Dial Food Thermometers

Bimetallic Furnace Proof Thermometers:
These thermometers have, in the probe, a double coil spring made of two different metals. These metals have different expansion rates. The spring, which is connected to the temperature indicator, expands in the heat. These types of thermometers measure the temperature at the tip and along the probe, up to a length of 2 to 2.5 inches. The resulting temperature is the average of the temperatures measured across the sensitive area. These food thermometers have a circular indicating dial and can be of two kinds, "oven proof" and "instant read".

Oven-Proof Bimetallic Thermometers: These food thermometers are designed to remain in food while it is cooking in the oven and are generally used for large foods, such as roasts or whole turkeys. This thermometer is very convenient because it constantly indicates the temperature of the food while it is cooking. However, if it is not left in the food throughout cooking, it will take 1 to 2 minutes to measure the correct temperature.

Bimetallic thermometers can accurately measure the temperature of relatively thick foods (such as roasts) or deep foods (such as foods cooked in broth). Because the sensing probe is relatively thick and 2 to 2½ inches long, these thermometers are not suitable for measuring the temperature of foods less than 3 inches thick.

Point and press the button to enlarge the image.Because metals conduct heat faster than food, there is a concern that the part of the food that is in contact with the tip of the thermometer is hotter than the rest of the food (the "effect of the nail on the potato"). To remedy this, it is recommended to measure the temperature in 2 and up to 3 different places of the food to check the temperature of this. Each time the thermometer is inserted into the food, let it equilibrate (come to temperature) for at least one minute before reading the temperature.

Some models of these thermometers can be calibrated. Consult the manufacturer's instructions.

Instant-Read Bimetallic Thermometers: These food thermometers measure the temperature of food quickly, in about 15 to 20 seconds. They are not designed to remain in the food while cooking in the oven; they should be used towards the end of the cook time to verify final temperatures. To prevent food from overcooking, check the temperature before the estimated cook time ends.


Point and press the button to enlarge the image. To obtain an accurate temperature measurement, the probe of the bimetal thermometer must be fully inserted into the food [usually about 2 to 3 inches]. When measuring the temperature of a thin food such as ground beef patties or boneless chicken breasts, the sensing probe should be inserted parallel to the surface so that the entire sensing element of the probe is inserted in the center of the food .

Temperature indicators for one-time use
One of the most recent advances in food retail is the appearance on the market of disposable temperature indicators. There are several brands and all of them can determine very quickly if food has reached the proper final temperature. These temperature indicators are designed for specific temperature ranges, for example, 160 to 170ºF (71.11 - 76.66ºC). It is important that these indicators are used only with the foods for which they were designed. Read the package directions to make sure the temperature the sensor is programmed to reach matches the proper cooking temperatures listed in this brochure.

These indicators are made with special heat sensitive materials. The indicator is inserted into the food and when it reaches the correct temperature, the indicator changes color. These indicators are designed for one-time use only. However, if the temperature has not reached the correct level when measuring, the indicator can be re-inserted several times until the proper temperature is reached. These types of temperature indicators cannot be left inserted in the food during cooking, they must be used towards the end of the calculated cooking time. To prevent food from overcooking, the temperature should be checked before the estimated cook time ends.

The disposable temperature indicators are manufactured from materials approved by the Food and Drug Administration (FDA) for contact with food.

Ejector temperature indicator:
Point and press the button to enlarge the image. This type of temperature gauge has been in use since 1965, usually on turkeys and broiler chickens. These devices are made from food-approved nylon. The interior contains a stainless steel spring and a detonator organic material. The organic detonator material is specifically designed to dissolve at specified, predetermined temperatures. Once the detonating material dissolves, the stainless steel spring releases the probe, allowing it to "pop (eject)". This ejection indicates that the food has reached the final temperature necessary to be safe and ready. The ejector indicators are fairly accurate, with a margin of error of only 1 or 2 degrees Fahrenheit, as long as they are properly positioned in the food; however, it is recommended to measure the temperature in other parts of the food with a conventional food thermometer. Checking with a conventional food thermometer is always recommended as an added precaution to cover both safety and thorough cooking.

Other types of food thermometers

Liquid column type thermometers in glass
Point and press the button to enlarge the image. Also called “liquor-filled” thermometers or “liquid-in-glass” thermometers, these are the oldest thermometers that have been used in the home kitchen. Thermometers of this type have a metal or glass tube. As the food heats up, the colored liquid inside the tube expands and rises to indicate the temperature on a scale. Heat conduction in metal tubes can cause false high temperatures to be read. These thermometers are designed to stay in the food while it cooks and should be inserted at least 2 inches deep so they are not suitable for measuring the temperature of thin foods. Some of the liquid-in-glass thermometers can be calibrated by carefully moving the glass tube inside the thermometer's protective sleeve.

Candy / Jelly / Frying Oil Thermometers:
Point and press the button to enlarge the image. These thermometers can measure temperatures between 100 and 400ºF (37.8 and 204.7ºC); They are used to measure the very high temperatures that are suitable for making candies and jellies, or for frying in boiling oil.

Thermometers for household appliances

Thermometers for refrigerators and freezers:
Point and press the button to enlarge the image. It is important to check the temperature of the refrigerators and freezers so that the food stays in good condition. Refrigerators must maintain a temperature no higher than 40ºF -or less. Frozen food will retain its best quality, for the longest time possible, if the freezer maintains a temperature of 0ºF (-17.8ºC) -or less. It is a good idea to place an appliance thermometer in the refrigerator and freezer to check the temperature of the appliances. This can be very useful when power outages occur. When the power returns, if the refrigerator registers 40ºF (4.4ºC) or lower and the freezer has been kept below 40ºF (4.4ºC), the food will have remained safe. These bimetallic spring thermometers are specially designed to accurately measure cold temperatures.

Thermometers for ovens:
Point and press the button to enlarge the image. A thermometer of this type can be left in the oven to verify that the oven is heating to the desired temperature. These bimetallic thermometers can measure temperatures from 100 to 600ºF (37.77 to 315.55ºC).