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Title: VISUAL COLOR AND DONENESS INDICATORS AND THE INCIDENCE OF PREMATURE BROWN COLOR IN BEEF PATTIES COOKED TO FOUR END-POINT TEMPERATURES

Author
item LYON, BRENDA
item BERRY, BRADFORD
item SODERBERG, D - USDA-FSIS
item CLINCH, N - USDA-FSIS

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: At a cooking temperature of 160 deg F (71.1 deg C), the harmful bacteria E. Coli O157:H7 is destroyed. Theoretically, ground beef patties that are brown all the way through have been heated higher than 160 deg F (71.1 deg C) to achieve this degree of doneness. However, there were several reports that some patties turn brown with no trace of red or pink at temperatures lower than 160 deg F (71.1 deg C). These reports led to concerns that consumer advice to cook their ground beef patties to the brown stage for safety might be inadequate. This study reports the results from an interagency effort by ARS and FSIS to study the incidence that patties from ground beef purchased at retail by a variety of buyers from a broad geographical sampling would turn brown at temperatures below 160 deg F (71.1 deg C). From the results of cooking and evaluating over 1500 burgers under a variety of conditions, this study concluded that visual assessment of color is not a reliable indicator of doneness and that consumers should use a meat thermometer to assure that the internal temperature of burgers reaches a minimum of 160 deg F (71.1 deg C).

Technical Abstract: An inter-laboratory study was undertaken to assess the frequency that cooked color of ground beef patties appeared brown at internal temperatures of 52.7 deg C (135 deg F), 65.6 deg C (150 deg F), 71.1 deg C (160 deg F) and 79.4 deg C (175 deg F). In general, as internal cooked temperature of the patties increased, the following results were observed in the patties: (1) more brown meat color, (2) less pink/red juice color and (3) more cooked texture. However, brown meat color occurred prematurely at the two lower internal temperatures (57.2 deg C/135 deg F and 65.6 deg C/150 deg F) that are insufficient to eliminate food borne pathogens without holding times. The common consumer practice of freezing bulk ground beef, followed by overnight thawing in a refrigerator, led to substantial premature brown color in patties cooked from this product. In addition, these indicators of doneness were not fully apparent at 71.1 deg C (160 deg gF), recognized to be the lowest temperature for cooking ground beef safel in the home. In fact, at no temperature studied did 100% of the patties appear done when evaluated by the criteria of no red/pink in the meat, or no red/pink in the juices, or by texture appearance. Patties in this study were evaluated under a set protocol for forming the products, cooking, and viewing under the same lighting conditions. Different preparation conditions may produce different results. Thus, temperature to which patties have been cooked cannot be judged by color and appearance. This study provided the evidence to support the FSIS message to consumers regarding cooking of beef patties of "use an accurate food thermometer and cook beef patties to 160 deg F (71.1 deg C)" in place of messages based upon consumer judgement of cooked color.