Microbial flora of commercially produced vacuum packaged, cooked beef roast

Commercially produced vacuum packaged, fully cooked, microwaveable beef roasts from four producers were purchased from local retail markets. Salt concentration, pH, water activity (aw), and percent moisture, fat and protein were determined. Samples of both package juice and homogenized beef plus juice were analyzed for the presence of aerobic, anaerobic and lactic acid bacteria and clostridia-type organisms. The cooked beef products had pH values from 5.82 to 6.19, water activity of 0.992 to 0.997, and contained 0.34 to 1.07% salt, 61.89 to 72.39% moisture, 4.29 to 18.21% fat and 15.92 to 20.62% protein. No growth was detected in juice for aerobic, anaerobic or lactic acid bacteria or clostridia-type organisms. Combined beef and juice had less than 2 CFU/g for aerobic, anaerobic or lactic acid bacteria or clostridia-type organisms. Cooking and chilling schedules used in the manufacture of the four products we evaluated in this study limited survival and outgrowth of microorganisms

Moisture uptake during washing and spray chilling of Holstein and beef-type steer carcasses

This study was conducted at a commercial beef slaughter plant to determine the effects of carcass washing, intermittent spray chilling and carcass fatness on carcass weight yields and on moisture content of cutaneous trunci muscle and s.c. adipose tissue (AT) samples excised from two carcass locations. Beef steer carcasses (n = 36) initially had 12.8% moisture in AT. Immediately following washing, AT from the sirloin region had more (P < .01) moisture (24.5%) than AT from the fifth-rib region (15.6%). Fat (n = 20) and lean (n - 20) carcasses were selected, and their right and left sides were allotted alternately to either a non-spray chill cycle or to an intermittent cold water spray-chilling cycle lasting either 3 or 6 h. After 20 h of chilling, carcasses subjected to the 6-h spray had 12.9% more (P < .01) AT moisture and possessed 2.6% more moisture in the cutaneous trunci muscle than similar samples from the non-spray chilled counterparts. In comparison, AT samples that were subjected to the 3-h spray had 3.9% more (P < .65) moisture, and the cutaneous trunci muscle had 2.0% more moisture, than their dry-chilled counterparts. After chilling, the spray-chilled AT had substantially higher (P < .01) moisture in the fifth-rib region (26.1%) than in the sirloin (14.8%). Spray-chilled sides in the 6-h cycle gained .3% of their hot carcass weight, whereas the corresponding non-spray sides shrank 1.2%. Spray-chilled sides subjected to the 3-h cycle shrank .4%, and their dry counterparts shrank 1.1%. Carcass washing and length of spray cycle had a greater influence than carcass fatness on surface tissue moisture retention. Modulation of these factors will help control post-chilling fluctuation of carcass weights in excess of USDA regulations and yet maximize carcass weight yields

The effects of porcine somatotropin (pST) dosage and dietary lysine level on growth performance and carcass characteristics of finishing swine

One hundred and forty-four finishing pigs (initial weight 126 lb) were utilized to determine the effects of PST dosage (4 or 8 mg PST' head^-1day^-1 ) and dietary lysine level (.8, 1,0, 1.2, or 1.4%) on growth performance and carcass characteristics. Pigs were injected daily in the extensor muscle of the neck with either 4 or 8 mg PST and fed a pelleted corn-soybean meal-sesame meal diet containing .8% lysine. Additional lysine levels of 1.0, 1.2, and 1.4% were provided by L-lysine HCl. Control pigs (placebo injection) received the .8% lysine diet. All diets were formulated to contain at least 220% of NRC (1979) recommendations for other amino acids, vitamins and minerals. There were no PST x lysine interactions for any observed traits (P>,1 0), so only main effects are reported. Increasing level of dietary lysine resulted in linear improvements in average daily gain (ADG) and feed conversion (F/G) in PST treated pigs. Adjusted backfat thickness (ABF) was lowered (linear P<.05), whereas longissimus muscle area (LMA) was increased (linear P<.05) with increasing lysine level. Pigs injected with 8 mg PST had similar ADG compared to 4 mg PST-treated pigs, and both were greater than controls (linear and quadratic P < .05%). Increasing PST dosage improved F/G (linear and quadratic P < .05), LMA and reduced ABF (linear P < .05). Urea concentrations determined in plasma on day 28 decreased (linear and Quadratic P<.05) with increasing lysine level, whereas free fatty acids and insulin tended to increase (P<.10). Porcine somatotropin dosage decreased urea concentrations while glucose, insulin and free fatty acid concentrations increased (linear and quadratic P < .05) in plasma. Trimmed ham and loin weights were increased slightly (P >.10) by increasing dietary lysine level and were also increased (linear P < .10) by PST dosage