Visual color and doneness indicators and the incidence of premature brown color in beef patties cooked to four end point temperatures

An interlaboratory study was undertaken to assess the frequency that cooked color of ground beef patties appeared brown at internal temperatures of 52 .7 degrees C (135 degrees F), 65.6 degrees C (150 degrees F), 71.1 degrees C (160 degrees F),and 79.4 degrees C (175 degrees F). In general, as intern al cooked temperature of the patties increased, the following results were observed in the patties: (i) more brown meat color, (ii) less pink or red j uice color, and (iii) more cooked texture. However, brown meat color occurr ed prematurely at the two lower internal temperatures (57.2 degrees C/135 d egrees F and 65.6 degrees C/150 degrees F) that are insufficient to elimina te foodborne pathogens without holding times. The common consumer practice of freezing bulk ground beef, followed by overnight thawing in a refrigerat or, led to substantial premature brown color in patties cooked from this pr oduct. In addition, at 71.1 degrees C (160 degrees F), recognized to be the lowest temperature for cooking ground beef safely in the home, meat color, juice color, and texture appearance were not fully apparent as doneness in dicators. In fact, at no temperature studied did 100% of the patties appear done when evaluated by the criteria of no red or pink in the meat, no red or pink in the juices, or by texture appearance. Patties in this study were evaluated under a set protocol for forming the products, cooking, and view ing under the same lighting conditions. Other preparation conditions are po ssible and may produce different results. Thus, temperature to which pattie s have been cooked cannot be judged by color and appearance. This study pro vided the evidence to support the message to consumers regarding cooking of beef patties of "use an accurate food thermometer and cook beef patties to 160 degrees F (71.1 degrees C)" in place of messages based on consumer jud gment of cooked color.