Author
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Berry, Bradford |
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Submitted to: Food Research International
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 2/14/1998 Publication Date: N/A Citation: N/A Interpretive Summary: Foodborne illnesses associated with the bacteria E. coli O157:H7 and inadequately cooked ground beef patties have highlighted the need for a reliable indicator of thorough cooking. Consumers are advised to cook beef patties until the interior is no longer pink. It is presumed that this occurs when the internal patty temperature reaches 160 deg F. However, there is growing evidence that some patties may appear fully cooked at temperatures below 160 deg F and other patties may look undercooked well beyond an internal temperature of 160 deg F. In this study, we evaluated wide variations in raw beef materials and two temperature end points (155 and 160 deg F) in terms of their influence of cooked beef patty color. Some color indicators showed an evidence of more brown pigment at 160 deg F compared to 155 deg F, but others did not. Patties processed from muscle with high pH (obtained by processing ground beef immediately following slaughter before chilling) displayed more pink/red color at both temperature end points. A higher occurrence of brown internal patty color was observed in patties processed from muscle obtained from young cattle. In any case, controlling muscle pH may be critical if consistent cooked patty color-final internal temperature relationships are to be attained. Use of an accurate temperature measuring device is suggested. Technical Abstract: Five separate formulations of ground beef patties were processed to represent differences in animal maturity, muscle pH, fat content and hot vs. cold processing. Patties were cooked on electric griddles to either 68.3 or 71 deg C before making visual and instrumental assessment of color. High pH muscle (whether obtained 48 h post-mortem or through hot processing) produced measurements more indicative of red, uncooked color, while patties from younger age cows (regardless of fat content) appeared more well-done. Patties processed from high pH (not hot processed) muscle had the highest saturation index and highest a* values (71.1 deg C only), but still required the longest cooking times to reach final internal temperatures. Reductions in a* values between 68.3 and 71.1 deg C temperatures were observed only for patties made from hot processed muscle. This may be related to the decrease in pH that occurred during cooking for this formulation. Differences in color between the two internal temperatures were minimal with patties cooked to 68.3 deg C possessing higher b* values, higher saturation index and lower hue angle (P < 0.01). Differences in ground beef formulations typical of those of this study may be responsible for the inconsistent cooked color-internal temperature relationships frequently observed with cooked patties. |
