Using a meat thermometer is a reliable way to ensure that food has reached the proper temperature. However, to be effective, thermometers must be used properly and calibrated correctly. If the thermometer is inserted incorrectly, or placed in the wrong area, the reading may not accurately reflect the internal temperature of the product. In general, the thermometer should be placed in the thickest part of the food, away from bone, fat or gristle. Read the manufacturer's instructions on how to calibrate (check the accuracy of) the thermometer.
According to the U.S. Department of Agriculture, temperature is the only way to gauge whether food is sufficiently cooked. USDA research reveals that the "color test" can give consumers misleading information about the safety of the foods they are preparing, since cooked color varies considerably. For example, freezing and thawing may influence a meat's tendency to brown prematurely.
The chart below provides information on different types of kitchen thermometers available, and tips to consider during their use. A graphic version of the chart suitable for printing is available in PDF format (13K).
Liquid-Filled Thermometer
Speed: 1-2 minutes
Placement: 2 inches deep in thickest part of food
Suggested Use: roasts, casseroles, soups
Considerations:
Bimetal (oven-safe) Thermometer
Speed: 1-2 minutes
Placement: 2 to 2-1/2 inches deep in thickest part of food
Suggested Use: roasts, casseroles, soups
Considerations:
Bimetal (instant-read) Thermometer
Speed: 15-20 seconds
Placement: 2 to 2-1/2 inches deep in thickest part of food
Suggested Use: roasts, casseroles, soups
Considerations:
Thermistor Thermometer
Speed: 10 seconds
Placement: 1/2 inch deep
Suggested Use: hamburger patty, pork chops
Considerations:
Thermocouple Thermometer
Speed: 5 seconds
Placement: 1/4 inch deep or deeper
Suggested Use: hamburger patty, pork chops
Considerations:
(Source: U.S. Department of Agriculture)
FDA Consumer magazine (September-October 1998)
This is a mirror of the page at http://www.fda.gov/fdac/features/1998/598_ther.html