ACCURACY, PRECISION AND RESPONSE TIME OF CONSUMER BIMETAL AND DIGITAL THERMOMETERS FOR COOKED GROUND BEEF PATTIES AND CHICKEN BREASTS*

Three models each of consumer instant-read bimetal and digital thermometers were tested for accuracy, precision and response time compared with a calibrated thermocouple in cooked 80 and 90% lean ground beef patties and boneless and bone-in split chicken breasts. At the recommended insertion times, the percent of measurements matching a calibrated thermocouple were 14–69% for bimetal and 0–64% for digital thermometers. Bimetals averaged 2–11F and the digitals averaged 1–20F less than the thermocouple readings. With longer insertion times, bimetals registered 25–81% and digitals registered 14–92% of the products as cooked. Bimetals averaged 1–9F and the digitals averaged 2–7F less than the thermocouples. Measurement repeatability (precision) was high within and between individual thermometers of the same model. Results indicate that the consumer thermometers evaluated in this study required more than the recommended time to register products as cooked. PRACTICAL APPLICATIONS Consumers are advised to use thermometers to ensure that meat products are properly cooked. Bimetal and digital thermometers are readily available to consumers. There has been no research conducted on the response times and accuracy of these types of thermometers in cooked meat products. Bimetal and digital thermometers underreported the actual product temperatures. It appears that these thermometers need additional time to register the product as fully cooked. Consumers using these thermometer models would assume that the product was not at the target temperature for food safety and would continue to cook the product longer. While this would ensure food safety by the product being overcooked, this could have a detrimental effect on the overall eating quality.