The influence of connective tissue content on amino acid composition and rat PER was studied in an attempt to develop a regression equation for predicting PERs of meat from the simple chemical analysis of collagen. Collagen content was highly correlated to essential amino acid content and rat PER with correlation coefficients of -0.99 and -0.98, respectively. The developed regression equation, PER = -0.02290 (collagen content) + 3.1528, effectively predicted rat PER within * 0.2 units when tested on various meat ingredients. These results indicated

SUMMARY —This research was to determine whether quantitative differences in total pigment and myoglobin concentration could be detected, chemically, in muscles which differed in visual color. For this purpose, a portion of the longissimus dorsi, psoas major, biceps femoris, and semitendinosus muscles was removed at specific locations, from choice‐grade steer carcasses, for use as experimental material. Each muscle was subjected to total pigment, myoglobin, fat, and moisture analysis. Hemoglobin content was determined by the difference between total pigment and myoglobin concentrations, Correction of total pigment and myoglobin concentration for fat and/or moisture was used to determine its influence upon the variation in the quantity of muscle pigmentation. Precise results were obtained with the total pigment and myoglobin procedures. Total pigment concentration was greatest in the biceps femoris and least in the semitendinosus. Little difference was obtained between the longissimus dorsi and psoas major. Myoglobin concentration, in decreasing order of magnitude, for the muscles studied was biceps femoris, longissimus dorsi, psoas major, and semitendinosus. The difference between myoglobin and total pigment concentration in the psoas major muscle was a result of hemoglobin constituting a greater portion of the total pigmentation. Results also indicated that hemoglobin contributed more to total pigment concentration and probably to muscle color than previously reported. The significance of the results obtained was not altered by correcting the data for fat and/or moisture.

The sodium dodecylsulfate‐acrylamide gel electrophoresis was evaluated as a method to determine the cooking temperature to which beef has been cooked. Water soluble protein extracts from bovine muscles cooked to the final temperatures of 65, 70, 75, 80, 85 and 90°C were applied on SDS‐acrylamide gels. The extracts showed characteristic electrophoretic patterns for each cooking temperature examined. The thermoprofiles were highly reproducible among a number of experimental variables. The high degree of accuracy and reproducibility of the method described herein makes it possible to determine the precise temperature to which beef has been cooked, within ± 5°C.

Two hundred broilers were commercially processed with and without electrical stunning to determine the effect of stunning on biochemical changes and its relationship to final meat tenderness. Electrically stunned birds were more tender with 30% lower shear values than no-stun controls after 24 hr aging. Breast muscles of electrically stunned birds showed significantly higher ATP, CP and pH, and lower lactate level than no-stun controls during the early processing steps. It was concluded that electrical stunning inhibited the rapid breakdown of ATP, CP and glycogen, and thus delayed the onset of rigor until after spin-chill by which time muscle temperature reached 4°C. Consequently, the rigor process occurred at low temperature where potential heat shortening was avoided, resulting in improved meat tenderness.

Foot-and-mouth disease virus was examined for its stability during cooking in tissues from infected cattle. The Oi (CANEFA 2) serotype of foot-and-mouth disease virus survived in lymph node tissues after heating for 2 hr at 69"C, for 1 hr but not for 2 hr at 82°C and for 1.5 min but not for 0.5 hr at 90°C. Incorporation of 1% NaCl into suspensions of infected lymph nodes enhanced viral survival after heating for 0.5 hr but not for 1 hr at 90°C. The virus did not survive in either ground beef or meatballs contaminated with infected lymph node tissue, when processed to internal temperatures of 93.3,96.1 or 98.8"C using commercial thermal processing procedures. Accurate temperature measurements were achieved with a temperature sensitive indicator disc developed in this study.