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ABSTRACT:The objective of these studies was to evaluate the effects of zilpaterol hydrochloride (ZH), fed for 0, 20, or 30 d, on meat quality attributes of calffed Holstein steers. Steers were slaughtered at a com mercial facility, and carcasses were selected by HCW to represent the pen mean. Further carcass selection was based on quality grade (Choice and Select) and yield grade. Proximate composition, measures of water holding capacity, and tenderness using Warner-Bratzler shear force after 7, 14, or 21 d postmortem were evalu ated on the shoulder clod (triceps brachii), top butt (gluteus medius), and strip loin (longissimus lumbo rum). Percentage of purge for the 3 subprimals was not different (P > 0.05) among ZH treatments. Steers fed ZH for 20 d or 30 d had decreased (P < 0.05) percent ages of fat in the triceps brachii, compared with 0-d ZH. Percentage of fat was less (P < 0.05) in the gluteus medius and longissimus lumborum when steers were fed ZH for 30 d compared with those steers fed ZH for 0 d. Percentage of fat was greater in Choice triceps brachii (P < 0.05) and longissimus lumborum (P < 0.10) com pared with Select. Thaw loss was not different (P > 0.05) for any muscle due to ZH treatment. Only longis simus had a greater (P < 0.05) cooking loss with ZH treatment. Cooking loss was not different (P > 0.05) for the gluteus medius or longissimus lumborum due to quality grade or aging day. At each aging day, the 20-and 30-d ZH longissimus lumborum had greater (P < 0.05) shear force values than 0 d; however, 20-and 30-d ZH had a greater absolute change in shear force from 7 to 21 d than that of 0 d ZH. Triceps brachii steaks were less tender (P < 0.05) after ZH treatment, but gluteus medius steaks were not different (P > 0.05). There was no difference (P > 0.05) in shear force due to quality grade. Results illustrate the use of ZH in calffed Holstein steers will have minimal effects on purge, thaw, or cooking loss. Percentage of intramuscular fat will decrease, especially when fed for longer durations. Steaks from ZH treated steers were tougher than steaks from control animals at all aging times, but ZH steaks became more tender with postmortem aging.

Our objectives were to characterize the effects of ractopamine hydrochloride (RAC) on fresh meat and further processing characteristics of muscles (serratus ventralis and triceps brachii) from the shoulders of finishing pigs. Two hundred forty shoulders originating from 120 carcasses (60 barrows and 60 gilts) were selected from a commercial population of pigs. A 2 × 2 factorial in a completely randomized design was used, with factors of RAC inclusion in the diet (0 or 7.4 mg/kg, as-fed basis) and sex (barrow or gilt). Paired shoulders (120 rights and 120 lefts) were transported from a federally inspected slaughter facility under refrigeration to the University of Illinois Meat Science Laboratory for evaluation. Subsequently, right and left shoulders were separated and designated for 2 separate experiments. Shoulders from right side were used in Exp. 1 to determine further processing characteristics. Cellar trimmed (CT) butts from the Boston butt of the shoulders were cured and dried-cured to manufacture cottage bacon and coppa, respectively. Shoulders from left side were used in Exp. 2 to determine fresh meat characteristics. Pigs fed RAC had greater shoulder weights and increased yields of cuts from the shoulder. Feeding RAC decreased Boston butt fat content (P = 0.01) but had no effect on picnic fat content (P = 0.86). Pigs fed RAC had greater (P < 0.01) iodine values than controls (67.00 vs. 64.95, respectively). Inclusion of RAC in the diet had no effect on cottage bacon cooked yield (P = 0.33), but it decreased (P < 0.01) cottage bacon fat content without having an effect on protein content (P = 0.50). In addition, cottage bacon from RAC shoulders had greater slice total area (P = 0.01) and less seam fat (P = 0.01) than controls. Ractopamine hydrochloride had no detrimental effect on coppa processing characteristics and visual appearance. Cottage bacon and coppa from RAC pigs had sensory characteristics similar to controls. Shoulders from pigs fed RAC might be of benefit to the industry because they provide more pounds of sellable product with no detrimental effects on processing characteristics.

HPP can be used on prerigor pork as means to improve fresh pork quality. Loins from HPP-treated pork sides had higher ultimate pH values and less package purge loss. Tenderness values were not affected positively or negatively by HPP treatment. The high pH and water-holding capabilities of treated samples have positive implications for further processing applications. Frankfurter textural properties suggest emulsified products can be made with pressurized pork without sacrifice to the textural profile.