NDSU Extension Service - Ramsey County


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Is It Done Yet?

Is It Done Yet?


As the temperatures have warmed up, grills have quickly moved out of storage and onto the patio or backyard for a favorite American past time – grilling food outdoors.  The aroma of a hot, sizzling hamburger off the grill unmistakable.  As the friends and family anxiously wait to enjoy the grill master’s creation, we may rush food off the grill and lose sight of food safety guidelines.

                That hamburger may look brown but is it done? One out of every four hamburgers turns brown before it’s been cooked to a safe minimum internal temperature. "Doneness" refers to when a food is cooked to a desired state and indicates the sensory aspects of foods such as texture, appearance, and juiciness. Unlike the temperatures required for safety, these sensory aspects are subjective.

We can’t rely upon color or texture alone to determine if meat, poultry or egg dishes are safe to eat. One of the critical factors in controlling bacteria in food is controlling temperature: pathogenic microorganisms grow very slowly at low temperatures, multiply rapidly in mid-range temperatures, and are killed at high temperatures.

Using a food thermometer is the only reliable way to ensure safety and to determine desired "doneness" of meat, poultry, and egg products. To be safe, these foods must be cooked to a safe minimum internal temperature to destroy any harmful microorganisms that may be in the food.

The temperature at which different pathogenic microorganisms are destroyed varies, as does the “doneness” temperature for different meat and poultry. A beef, lamb, or veal roast, steak, or chop that is not pierced in any way during processing or preparation and reaches an internal temperature of 145 °F is safe to eat. Cook steaks, roasts, or chops that have been tenderized, boned, rolled, etc., to a safe minimum internal temperature of 160 °F. A pork chop or roast cooked to 160 °F is safe to eat. For safety and quality, allow meat to rest for at least three minutes before carving or consuming.

Likewise, all poultry should reach a safe minimum internal temperature of 165 °F. For reasons of personal preference, consumers may choose to cook poultry to higher temperatures for acceptability and palatability.

A food thermometer should also be used to ensure that cooked food is held at safe temperatures until served. Cold foods should be held at 40 °F or below. Hot food should be kept hot at 140 °F or above.    
                What type of food thermometer to use?  Food thermometers come in several types and styles and range in level of technology and price.

Digital Food Thermometers/Thermocouple: Of all food thermometers, thermocouple thermometers reach and display the final temperature the fastest - within 2 to 5 seconds. The temperature is indicated on a digital display. A thermocouple measures temperature at the junction of two fine wires located in the tip of the probe.  Since thermocouple thermometers respond so rapidly, the temperature can be quickly checked in a number of locations to ensure that the food is safely cooked. This is especially useful for cooking large foods, such as roasts or turkeys, when checking the temperature in more than one place is advised. The thin probe of the thermocouple also enables it to accurately read the temperature of thin foods such as hamburger patties, pork chops, and chicken breasts. Thermocouples are not designed to remain in the food while it's cooking. They should be used near the end of the estimated cooking time to check for final cooking temperatures.

Thermometer Fork Combination:  This utensil combines a cooking fork with a food thermometer. A temperature-sensing device is embedded in one of the tines of the fork. There are several different brands and styles of thermometer forks on the market; some using thermocouples and some using thermistors. The food temperature is indicated on a digital display or by indicator lights on the handle within 2 to 10 seconds (depending on the type). These lights will tell if the food has reached rare, medium, well done, etc. Particularly useful for grilling, the thermometer fork will accurately measure the internal temperature of even the thinnest foods. The thermometer fork should be used to check the temperature of a food towards the end of the estimated cooking time. Thermometer forks are not designed to remain in a food while in the oven or on the grill and cannot be calibrated.

Oven-safe Bimetallic-coil Thermometers: This food thermometer is designed to remain in the food while it is cooking in the oven, and is generally used for large items such as a roast or turkey. It is convenient because it constantly shows the temperature of the food while it is cooking. However, if not left in the food while cooking, they can take as long as 1 to 2 minutes to register the correct temperature. The bimetal food thermometer can accurately measure the temperature of relatively thick foods (such as beef roasts) or deep foods (foods in a stockpot). Because the temperature-sensing coil on the stem is between 2 to 2 1/2 inches long and the stem is relatively thick, it is not appropriate to measure the temperature of any food less than 3 inches thick.

Pop-Up Timers:   Commonly used in turkeys and roasting chickens since 1965, the "pop-up" style disposable cooking device is constructed from a food grade nylon. The inside contains a stainless steel spring and organic firing material. The organic firing material is specifically designed to dissolve at specific predetermined temperatures. Once the firing material dissolves, the stainless steel spring releases the stem, allowing it to "pop up." This indicates that the food has reached the correct final temperature for safety and doneness. Pop-up style disposable cooking devices are reliable to within 1 to 2 °F, however, proper placement is important. Checking with a conventional food thermometer is always recommended as an added precaution to properly gauging both safety and doneness.

Liquid-filled Thermometers:  Also called "spirit-filled" or "liquid in glass" thermometers, these thermometers are the oldest kind of food thermometer used in home kitchens. They have either metal or glass stems. As the internal temperature of the food increases, the colored liquid inside the stem expands and rises to indicate the temperature on a scale. Heat conduction in the metal stems can cause false high readings. They are designed to remain in the food while it is cooking. They should be inserted at least 2 inches deep in the thickest part of the food, and are, therefore, not appropriate for thin foods. Some liquid-filled thermometers can be calibrated by carefully moving the glass stem within the holder.

Refrigerator/ Freezer Thermometers: Refrigerators should maintain a temperature of 40 °F or below. Frozen food will hold its top quality for the longest possible time when the freezer maintains 0 °F or below. An appliance thermometer can be kept in the refrigerator and freezer to monitor the temperature. This can be critical in the event of a power outage. When the power goes back on, if the refrigerator is 40 °F or below, and the freezer is still colder than 40 °F, the food is safe. These bimetallic-coil thermometers are specially designed to provide accuracy at cold temperatures.
          To achieve an accurate reading, use the following guide to determine where to insert whatever type of thermometer you are using.

              Beef, lamb, pork roast: Insert into the thickest part of the roast, avoiding the bone and fat. Remove the roasts from the grill 5 to 10 degrees F below final doneness. Tent with aluminum foil. Let stand for 15 minutes. The temperature will continue to rise to reach final doneness. During standing, the meat juices redistribute and the roast becomes easier to slice.

Burgers, steaks, chops: Insert horizontally into the center, away from bone and fat.

Whole poultry: Gauge the temperature at part of the thigh, avoiding the bone.

Poultry parts: Insert thermometer in the thickest area, avoiding the bone.

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