Michael E. Dikeman

Mesophilic and Psychrotrophic Bacterial Populations on Hot-Boned and Conventionally Processed Beef'

Mesophilic and psychrotrophic bacterial counts of hot-boned and conventionally treated cuts from 15 steers were low [Log 0-2 colony forming units (CFU)/cm2] at 0 time; and after 14 days of vacuum-packaged storage (2.2 C), hot-boned cuts had higher counts than conventionally-treated cuts. In the first experiment involving 10 steers, the mesophilic and psychrotrophic counts for hot-boned cuts were Log 5.26 CFU/cm2 and Log 5.15 CFU/cm2, respectively, and for conventionally treated cuts, log 4.64 CFU/cm2 and Log 4.43 CFU/cm2, respectively. In the second experiment involving 5 steers, the mesophilic and psychrotrophic counts were Log 6.62 CFU/cm2 and Log 6.61 CFU/cm2, respectively, for hot-boned cuts; and Log 5.93 CFU/cm2 and Log 4.91 CFU/cm2, respectively, for conventionally treated cuts. Some hot-boned cuts had low levels (Log 0-3 CFU/cm2) of coliforms, fecal coliforms, Clostridium perfringens , coagulase-positive Staphylococcus aureus and fecal streptococci. No Salmonella were recovered from any cuts. Temperature-decline data indicated that hot-boned cuts had longer (several hours) periods of rapid bacterial growth (above 21 C) than conventionally-treated cuts. The longer rapid growth period for hot-boned cuts may have contributed to higher microbial loads and subsequently to more growth of bacteria in cold storage. Slower chilling of hot-boned samples stemmed from vacuum-packaging and boxing soon after cutting. Temperature control of hot-boned meat during the first several hours of chilling is critical, particularly if hot cuts are vacuum-packaged and boxed before chilling. Some temperature decline guidelines, based on bacterial counts, are presented for hot-boned, vacuum-packaged boxed cuts. Most hot-boned cuts processed and stored under our experimental conditions were bacteriologically acceptable.

Initial Chilling Rate Effects on Bacterial Growth on Hot-Boned Beef1

We studied the chilling rate of hot-boned beef required to control bacterial growth during storage and display. Hot-boned cuts were chilled to 21 C by 3, 5, 9, and 12 h after their removal from the carcass. Cuts were vacuum-stored at 2.2 C for 14 or 21 d, then displayed at 2.2 C for 3 days under natural fluorescent lighting. Initial bacterial loads of hot-boned cuts were low (Log 0-3 CFU/cm2). Conventionally chilled beef (48 h at 2.2 C) and hot-boned cuts chilled to 21 C by 3, 5, and 9 h had lower bacterial counts and more desirable color and odor than hot-boned cuts chilled slower (12 h to 21 C). In general, indicator organisms and potential pathogens (coliforms, fecal coliforms, coagulase-positive Staphylococcus aureus , Clostridium perfringens , and fecal streptococci) were more numerous for cuts with slower chilling rates (9 and 12 h to 21 C) than for cuts chilled faster (3 and 5 h to 21 C and conventionally chilled beet). No Salmonella were detected. Hot-boned beef cuts are in good bacteriological condition (no potential health hazards) for storage if chilled to 21 C in 3 to 9 h.

Effects of zilpaterol hydrochloride feeding duration on crossbred beef semimembranosus steak color in aerobic or modified atmosphere packaging.

The objective of this research was to determine the effects of feeding zilpaterol hydrochloride (ZH) for 0, 20, 30, or 40 d before slaughter (ZH0, ZH20, ZH30, or ZH40, respectively) on semimembranosus (SM) color development and stability. A 7.62-cm-thick portion was removed from 60 beef steer SM subprimals and stored (2 degrees C) for 21 d; then two 2.54-cm-thick steaks were cut, overwrapped with polyvinyl chloride (PVC) film, and assigned to 0 or 3 d of display. Remaining portions of the subprimals were stored in a vacuum for 10 d and then enhanced 10% to a meat concentration of 0.3% sodium chloride, 0.35% phosphate, and 0.05% rosemary extract. Steaks were packaged in a high-oxygen (HO-MAP) or carbon monoxide (CO-MAP) modified atmosphere and assigned to 0, 3, or 5 d (HO-MAP) or 0 or 9 d (CO-MAP) of display. The deep (DSM) and superficial (SSM) portions of steaks were evaluated for initial color, display color, discoloration, pH, L*, a*, b*, hue angle, and saturation indices. For steaks in PVC, no differences (P > 0.05) occurred in initial or discoloration color scores because of ZH feeding duration. The enhanced SSM steaks from ZH20 in PVC were brighter red (P < 0.05) than SSM steaks from ZH40 in PVC. The DSM in PVC had less (P < 0.05) pH and paler (P < 0.05) color than the SSM. Display color scores for the DSM of PVC steaks were brighter red (P < 0.05) than the SSM initially (d 0 and 1), but the DSM discolored faster (P < 0.05) than the SSM on d 1 to 3. The SM steaks from steers fed ZH20 or ZH30 were slightly brighter and less discolored during display in PVC than the ZH40 diet. For enhanced steaks in HO-MAP, the DSM of ZH20 and ZH30 diets displayed 4 d and the DSM of ZH20 displayed 5 d was a brighter (P < 0.05) red than the DSM from ZH40. At display d 1 and 5, the SSM of ZH20 steaks in HO-MAP was a brighter (P < 0.05) red than SSM steaks from ZH40. The SSM of ZH40 HO-MAP steaks was darker (P < 0.05) red on d 3 than the SSM from other diets. For enhanced steaks in CO-MAP, ZH30 steaks were brighter (P < 0.05) red than ZH0 or ZH40 steaks on d 0 and 9 of display. Steaks in CO-MAP from all feeding durations were less than 20% discolored through d 9. The DSM was lighter (P < 0.05) than the SSM on d 0 for steaks packaged in HO-MAP and CO-MAP. Feeding cattle ZH for 20 or 30 d will yield steaks with color characteristics equal to or better than steaks from control cattle, whereas feeding ZH for 40 d will likely produce less desirable meat color traits.

Predicting cattle age from eye lens weight and nitrogen content, dentition, and United States Department of Agriculture maturity score

This research explores the relationship between generally accepted and alternative cattle age-prediction methods and chronological age. Cattle (n = 386) of documented ages ranging from 370 to 1,115 d of age were used. Dentition (DEN), USDA maturity score (MS), lens weight (LW), and lens total N (LN) content were used as possible predictors of age. Correlations with age were determined: LW (r = 0.77); DEN (r = 0.74); LN (r = 0.71); and MS (r = 0.64). Stepwise backward regression was used to generate an age prediction equation: Age (mo) = -21.79 + 17.23(LW, g) + 0.038(DEN). By this equation, 38% of cattle </= 20 mo of age were verified as </= 20 mo of age. Independent measures verified the following percentages of cattle as </= 20 mo of age: LW (20.2%), MS (11.0%), DEN (9.6%), and LN (8.7%). The DEN verified that 87.6% were verified as <30 mo old, and LW verified 81.6% of cattle as <30 mo old. A separate group of cattle (n = 18) ranging in age from 1 to 12 yr were evaluated for lens properties, for which LW (R(2) = 0.91) and LN (R(2) = 0.92) were highly correlated with age. The LW and DEN were the best predictors of age for cattle 13- to 37-mo-old and yielded the most accurate age prediction when used in combination (R(2) = 0.67).

The effect of Dakota Gold®-brand dried distiller’s grains with solubles of varying levels on sensory and color characteristics of ribeye steaks

We evaluated the effect of varying levels of Dakota Gold-brand dried distillers grains with solubles (DDGS) on meat quality characteristics including sensory traits and display color stability. Rib cuts from heifers from a 153-day feeding trial were selected randomly so that each level of DDGS had 10 steaks in a seven-day retail display color study, and 10 steaks that were cooked for evaluation by a trained sensory panel. Color reflectance value L* (lightness) exhibited an interaction (P<0.05) between diet and day, as well as a quadratic effect (P<0.05). Diet had no effect on a* (redness) or b* (yellowness) values, but a* and b* for all treatments decreased with longer display (P<0.05). A trained sensory panel detected small but significant (P<0.05) linear improvements in myofibrillar tenderness and overall tenderness as DDGS increased. The effect on sensory traits or display color stability were too small to warrant the feeding of DDGS to improve these traits.

Comparison of feeding calves vs. yearlings

This report is brought to you for free and open access by New Prairie Press. It has been accepted for inclusion in Kansas Agricultural Experiment Station Research Reports by an authorized administrator of New Prairie Press. Copyright 1992 Kansas State University Agricultural Experiment Station and Cooperative Extension Service.

Effect of Ralgro® implantation periods on masculinity and carcass traits of young bulls and steers.

This report is brought to you for free and open access by New Prairie Press. It has been accepted for inclusion in Kansas Agricultural Experiment Station Research Reports by an authorized administrator of New Prairie Press. Copyright 1984 Kansas State University Agricultural Experiment Station and Cooperative Extension Service.

Effects of Finaplix®, Synovex-S® and Ralgro® implants, singularly or in combinations, on performance, carcass traits and longissimus palatability of Holstein steers

This report is brought to you for free and open access by New Prairie Press. It has been accepted for inclusion in Kansas Agricultural Experiment Station Research Reports by an authorized administrator of New Prairie Press. Copyright 1990 Kansas State University Agricultural Experiment Station and Cooperative Extension Service.

Timing of trenbolone acetate implants on performance, carcass characteristics, and beef quality of finishing steer calves

Angus and Angus-cross calves (632 lb) were utilized in a finishing study to evaluate the effects of implanting with estradiol and progesterone (Synovex-S®) and(or) trenbolone acetate (Finaplix®) on performance of finishing steers. Over the entire finishing period (117 d), implanted steers had higher (P<.05) daily gains and were more efficient than nonimplanted steers. Carcasses from implanted cattle had heavier (P<.05) hot weights and larger (P<.05) ribeye areas. Steers implanted with Finaplix had larger (P<.05) ribeye areas than those implanted with Synovex only. Marbling scores and quality grades were not affected by implant treatments. Rib (9-10-11) sections from implanted steers were heavier (P<.05) as a result of both heavier (P<.05) bone and soft tissue weights. However, no differences in percentages of protein, fat, and moisture were detected by proximate analysis of the soft tissue. Concomitant use of Finaplix with Synovex-S did not affect performance of Angus and Anguscrossed steer calves.

Practical aspects of beef carcass traceabilityin commercial beef processing plants using an electronic identification system

The use of an electronic identification (EID) system in slaughter facilities holds great potential as a tool for animal and carcass traceability, if used as part of a comprehensive carcass tracking system. However, the correct association of each carcass with its individual EID tag number may be hindered at several points during the slaughter process. For 2,994 cattle slaughtered in 14 lots and bearing buttontype, full duplex EID ear tags, 113 (3.92%) had non-functional tags, 16 (0.53%) had no tag, and 37 extra head were introduced accidentally into one of our lots. Of the 2,994 carcasses, 71 (2.37%) were railed out for further trimming, 8 (0.27%) were retained for further inspection, 3 (0.10%) were condemned, and 1 carcass fell from the rail. For the plant in which data were collected, the hot-carcass scale operator ultimately had the responsibility for assuring that lots of carcasses accurately represented lots of cattle slaughtered. Although the current systems in some plants may be adequate for cattle traded on a live basis, they may not insure exact matching of live animals and their respective carcasses.