RESUMEN
The influence of modified atmosphere packaging and barrier properties of films upon product attributes of frozen (IQF) turkey strips was evaluated every 28 d over a duration of 196 d. Three gases/mixtures were used (CO2, N2, and ambient air) for flushing two pouches, a pouch made from normal barrier film (861) and a pouch made from a high barrier film (863). The triangle test and organoleptic evaluations were performed separately by a semitrained panel (six members) on the following traits: freshness, structure, mouth feel, overall evaluation, aroma, appearance, and off-flavors. Results from the overall evaluation scores indicate this score was greatly influenced by storage period. Products stored up to 84 d had the highest scores, and the lowest score was for products stored for 196 d. The overall evaluation score was slightly higher for products stored in pouches made from high barrier film. Panelists using the triangle test for each of the seven periods were able to detect differences between treatments 86, 69, 83, 81, and 86% of the time for products stored in 861/CO2, 861/N2, 861/ambient, 863/CO2, and 863/N2, respectively. Products packaged in N2 had the lowest thiobarbituric acid value while products stored in ambient atmosphere had the highest thiobarbituric acid value. Microbial evaluation of the product indicated those microorganisms studied were not influenced by the factors included in this study.
RESUMEN
Thirty beef carcasses were used to evaluate the effects of electrical stimulation and conditioning periods and microwave cooking upon sensory and shear properties of pre-rigor semitendinosus muscle samples. The intact muscle was removed from the right side within 45 min post-exsanguination and was electrically (ES) stimulated [100 impulses (1 s on and 1 s off, A.C., 110V, <5 amps)], while the remaining paired muscle served as the control (NS). After electrical stimulation, the muscle was cross-sectioned into three portions. A 2.54-cm thick sample was removed from the central portions of the ES and NS muscles and cooked immediately in a microwave oven to an internal temperature of 66°C. The remaining two similar sized portions were conditioned at 13°C for 2 h or 4 h before cooking. Three cores (1.27 cm) were removed from each sample parallel to the muscle fiber, and all cores were sheared twice. Samples from the conditioning periods were frozen, thawed, reheated and evaluated for palatability traits by a 10-member trained panel. Results indicate higher sensory panel ratings (P<.05) for tenderness, connective tissue and flavor intensity and lower shear force (WBS and Instron) values and longer sarcomeres from ES. With the conditioning periods used, microwave cooking was too rapid for pre-rigor muscle, as exemplified by the high shear values (6.4 and 7.8 kg/1.27 cm for ES and NS, respectively) which indicates a very tough sample of meat. Cooking yield was highest for muscle samples cooked immediately after slaughter. Roasts conditioned for 4 h before cooking had higher (P<.05) juiciness and flavor intensity scores than roasts held for 2 h, regardless of stimulation treatments.
RESUMEN
The effects of electrical stimulation on palatability of hot-boned, pre-rigor and cold-boned, post-rigor frozen beef roasts were studied by use of 16 steer carcasses. Both sides of 8 carcasses were electrically stimulated (1.5 amps; 100 - 1 s impulses); sides from the other 8 carcasses served as controls. One side of each carcass was hot-boned and the remaining side was boned following a 48 h chill (2 C). Roasts from the rump portion (anterior one-fourth) of the biceps femoris muscle were vacuum-packaged and frozen (-20 C). Following a 48-h thaw (0 C). roasts were weighed, measured for length, width and depth, seasoned, placed in cooking bags and roasted to 62.5 C. Cooking losses were less (P<0.06) for hot-boned, pre-rigor frozen vs. cold-boned, post-rigor frozen roasts. Raw pH (post-freezing) was lower (P<0.01) for hot-boned than cold-boned roasts. No differences (P>0.05) were noted in shape changes for stimulation or chilling. Using triangle tests, untrained panel members were able to distinguish controls from electrically stimulated roasts and hot-boned from cold-boned roasts when served as thick (1.27 cm) or thin (2 mm) samples. Thick and thin samples of cold-boned roasts were preferred over hot-boned roasts. For roasts from carcasses that were not electrically stimulated, 62.6% preferred cold-boned roasts for thick samples while 61.4% preferred cold-boned roasts for thin samples. Cold-boned roasts from electrically stimulated carcasses were preferred over hot-boned roasts, 56.5% (thick) vs. 51.5% (thin). Warner-Bratzler shear force results indicated that hot-boned, control roasts required 79% more shear force than cold-boned roasts, but roasts from electrically stimulated carcasses required 14% more force to shear hot-boned than cold-boned roasts.
RESUMEN
Beef heifers in a feedlot were fed an experimental (E) diet containing gamma-irradiated ("pasteurized") dried sewage solids as 20% of the diet. Similar heifers received a conventional diet and served as controls (C). Four heifers from each group were slaughtered at the 68th day of the feeding program. Carcasses from E were smaller than from C (202 versus 245 kg), had less fat thickness (.76 versus 1.0 cm) and less internal fat (2.5 versus 2.9%). Steaks, roasts and ground beef (composite of all trimmings) were displayed for 3 d in a refrigerated (2-4°C) meat case. Ground meat from E was superior to C in lean color and overall visual acceptance; but the reverse was true for steaks and roasts (P<.05). Steaks and roasts from C were evaluated slightly higher than E in firmness of lean, resulting from more subcutaneous carcass fat of C. Microbial contamination of carcasses was assayed by cultures from swabs taken from the diaphragm muscle and the 12/13th rib area of hanging sides (at slaughter and days 2 and 7 postmortem) and from swabs and core samples of product at day 0 and days 3 and 17 postmortem. Colony counts from core samples taken from bulk ground beef (C) and soaked in peptone water averaged 8.5 × 104 for day 0 and 7.5 × 106 for day 3 samples, while samples from E carcasses averaged 3.8 × 104 (day 0) and 4.1 × 107 (day 3). Colony counts from surface swabs of beef patties averaged 4.6 × 104 (day 0) and 5. 7 × 106 (day 3) for C and 6.5 × 104 (day 0) and 9.4 × 106 (day 3) for E. Microbial counts of the product surveyed in this study did not differ (P>.05) due to diets (E vs. C). Livers and kidneys from cattle fed the E diet had higher levels (P<.05) of Fe and Pb than those from cattle receiving the C diet.
