The effect of different on-line dressing practices on microbiological and visible contamination of lamb carcasses

Three dressing practices were assessed in traditional lamb carcass dressing systems for their ability to improve control of microbiological and visible contamination. The routine removal of a piece of skin from the perineal area reduced total aerobic plate counts and Escherichia coli counts on carcasses derived from both woolly and shorn groups of lambs. Similar results were found when the "Y-cut" was delayed in the dressing sequence, but E. coli counts increased slightly in one group. The use of a wide-blow shear prior to the opening cut on the hindleg of carcasses derived from woolly lambs resulted in a slight increase in the microbiological contamination on the leg. The removal of a piece of skin from the perineal area reduced scores for faecal contamination despite a small increase in contamination with wool. Changes in visible contamination in response to the two other dressing procedures were principally effected through changes in levels of contamination with wool. Irrespective of dressing procedures, levels of microbiological and visible contamination were lower on carcasses derived from shorn compared with woolly lambs. These studies demonstrated that, although they are reasonable indicators, the use of parameters of visible contamination as a measure of carcass hygiene must be treated with caution. This is especially the case if a genuine HACCP-based system for the control of dressing hygiene for a particular class of slaughtered livestock is to be implemented.     

Effects of chlorination of chill water on the bacteriologic profile of raw chicken carcasses and giblets.

In March 1989, the USDA Food Safety and Inspection Service sampled raw chicken carcasses and giblets at a federally inspected slaughter establishment in Puerto Rico to determine the effects of adding chlorine to carcass and giblet chill water on bacterial contents of raw poultry products. Over four 8-hour workdays, 200 carcass rinse samples were collected at 3 sites in the establishment; 39 giblet rinse samples were collected at 1 site. Analyses of the carcass rinse samples indicated that carcasses had average aerobe plate counts of log10 3.20 before chilling and 2.51 after chilling; Enterobacteriaceae counts of log10 2.57 before chilling and 1.75 after chilling; and Escherichia coli counts of log10 2.04 before chilling and 1.20 after chilling. Salmonellae were found on 43% of the carcasses before chilling and on 46% after chilling. Analyses of the giblet and neck rinse samples indicated that raw giblets and necks after chilling had average aerobe plate count of log10 3.49, Enterobacteriaceae count of log10 2.57, and E coli count of log10 1.06. Salmonellae were found on 12% of the giblets and necks sampled. Results compared favorably with giblet and neck rinse sample results obtained during a baseline sampling study in November and December 1987. The baseline results indicated aerobe plate count of log10 3.72; Enterobacteriaceae count of log10 2.90; E coli count of log10 1.14; and salmonellae on 69% of the giblets and necks sampled. Placing raw chicken carcasses in chlorinated chill water reduced aerobe, Enterobacteriaceae, and E coli plate counts. Prevalence of carcasses with salmonellae remained nearly the same.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of countercurrent scalding and postscald spray on the bacteriologic profile of raw chicken carcasses.

In June and September 1988, the USDA Food Safety and Inspection Service sampled raw chicken carcasses at a federally inspected slaughter establishment in Puerto Rico to determine the effects of changing the scalding equipment on bacterial contents of raw poultry products. The scalding equipment was changed to a countercurrent configuration, with a postscald hot-water rinse cabinet that sprayed carcasses as they exited the scalder. Analysis of 250 carcass-rinse samples collected at preevisceration, prechill, and postchill sites over 7 days indicated that carcasses had mean aerobe plate counts of log(10)3.73 before evisceration, 3.18 before chilling, and 2.87 after chilling; Enterobacteriaceae counts of log(10)2.70 before evisceration, 2.25 before chilling, and 1.56 after chilling; and Escherichia coli counts of log(10)2.09 before evisceration, 1.61 before chilling, and 0.89 after chilling. Salmonellae were found on 24% of the carcasses before evisceration, on 28% before chilling, and on 49% after chilling. Although bacterial count reductions were significant at all 3 sites, the proportion of carcasses contaminated with salmonellae in this study was higher at the postchill than prechill site (49 vs 28%). This no doubt was caused by cross-contamination in the chiller. These percentages indicated that although simple scalder changes contributed substantially to the improvement of the bacterial quality of chicken carcasses, additional interventions in the chilling process (such as chlorination of chill water) are important to control cross-contamination and to preserve the positive effects obtained by the scalder changes.     

萨福克杂交组合F_1代羔羊屠宰性能测定

为测定不同杂交组合F1代羔羊屠宰性能,利用引进的国外优质肉用萨福克羊与本地绵羊进行杂交,对杂交羔羊屠宰性能进行测定。结果表明,萨土杂交一代羔羊的宰前活重（49.50 kg）、胴体重（23.20 kg）、屠宰率（59.04%）、肉骨比（3.89）,眼肌面积（15.50 cm2）显著高于本地土种羊（P〈0.05）;萨细组合宰前活重（45.4 kg）、胴体重（22.8 kg）、屠宰率（57.09%）、肉骨比（3.03）、眼肌面积（13.50 cm2）显著高于本地细毛羊（P〈0.05）。故利用萨福克羊杂交改良本地绵羊,在提高屠宰性能方面取得了较好的效果。     

Profile of selected bacterial counts and Salmonella prevalence on raw poultry in a poultry slaughter establishment.

The USDA Food Safety and Inspection Service determined populations of bacteria on poultry during processing at a slaughter plant in Puerto Rico in November and December 1987. The plant was selected because of its management's willingness to support important changes in equipment and processing procedures. The plant was representative of modern slaughter facilities. Eight-hundred samples were collected over 20 consecutive 8-hour days of operation from 5 sites in the processing plant. Results indicated that slaughter, dressing, and chilling practices significantly decreased the bacterial contamination on poultry carcasses, as determined by counts of aerobic bacteria, Enterobacteriaceae, and Escherichia coli. Salmonella was not enumerated; rather, it was determined to be present or absent by culturing almost the entire rinse. The prevalence of Salmonella in the study decreased during evisceration, then increased during immersion chilling.     

Congenital cataracts in an Ayrshire herd: a herd case report

Background

Microbiological standards within pork slaughter processing plants in the European Union are currently governed by Commission Regulation (EC) 2073/2005, which describes detailed performance criteria at specific stages of the procedure (following carcass dressing and before chilling) for total viable counts (TVC), Enterobacteriaceae (EB) and Salmonella spp. In this study, 95 carcasses from an Irish pork slaughter plant were sampled by swabbing 100 cm² of surface at three sites (belly, ham, jowl) to examine the effects of eight processing stages (stunning, bleeding, scalding, singeing, polishing, evisceration, final inspection and chilling) on contamination levels.

Results

TVC ranged from approximately 1.7–6.3 log cfu cm² during sampling. There were significant reductions in TVC for all sites after scalding and singeing (p < 0.05), whilst there was a significant increase in counts after polishing and evisceration (p < 0.05) compared with preceding stages. EB counts indicated hygienic weak points in the examined slaughter plant leading to faecal (cross)-contamination, with elevated counts after stunning, bleeding and evisceration (p < 0.05), compared with final counts after chilling.

Conclusions

Although the bacterial numbers reported in this study may reflect specific plant practices and temporal influences, results show that contamination can be introduced at various steps in the process and highlight the importance of monitoring locations other than those required by legislation within the process. Monitoring can be used to establish baseline levels for high-risk stages specific to each plant and to assess the effectiveness of additional interventions.     

Economics of callipyge lamb production

This paper examines the economic implications of callipyge (CLPG) lamb production. The price, as it relates to competing meats and excess fat, significantly impact lamb demand, and CLPG genetics improves those factors. The CLPG phenotype does not affect number or weight of lambs weaned or postweaning ADG, but it does improve postweaning feed efficiency by approximately 10%; dressing percentage approximately 7.5%; and yields of wholesale leg (11.8%), loin (4.7%), rack (2.5%), and shoulder (2.3%). Total production costs for a 59-kg lamb are 4% lower in CLPG lambs due to improved feed efficiency. Assuming pelt and offal value pays for slaughter costs, the costs of normal (N) and CLPG carcasses are the same as for live lambs, $81 and $78, respectively; but, due to dressing percentage, the N carcass weighs 29.2 kg and the CLPG carcass, 31.4 kg. Thus, carcass costs for N and CLPG lambs are $2.77/kg and $2.49/kg, respectively. Decreased feed costs, combined with increased carcass and primal cut yields for CLPG lambs, lowers the price required to recover meat costs for leg, loin, rack, and shoulder by 19.7, 14.4, 12.6, and 11.9%, respectively. Successful marketing of CLPG loin and rack depends on the use of one of several postharvest tenderization procedures. Moisture-enhanced pork is accepted by consumers and often sells for a premium; and moisture enhancement may be appropriate for CLPG lamb. The meat cost per kilogram (including a $.10 per kilogram treatment cost) of tenderized and moisture-enhanced CLPG leg, loin, rack, and shoulder containing 10% added water and ingredients would be lowered to $2.51, $4.65, $5.34, and $1.85, respectively. That represents a total of a 20.9% reduction in cost-basis price. When expressed on the basis of increased revenue from the additional yield of cuts at a given market price, the value of CLPG and moisture-enhanced CLPG cuts from a 59-kg lamb would be, respectively, 14.2% and 23.4% higher than for N lamb. Industrywide adoption of CLPG could increase intermediate-run U.S. profits by $109 million, but the actual effects of CLPG attributes, such as a visual appeal, lower fat and cholesterol content, and reduced seam fat, on consumer demand need to be quantified. If accepted by packers and consumers, moisture-enhanced CLPG lamb has the potential to decrease the cost of lamb to consumers and increase lamb industry profitability.     

Effectiveness of steam pasteurization in controlling microbiological hazards of cull cow carcasses in a commercial plant

The purpose of the study, carried out in a beef processing plant, was to evaluate the effectiveness of a new prototype for steam pasteurization treatment in controlling microbiological hazards. Samples were taken by swabbing randomly selected sites before and after pasteurization and again after chilling to obtain total aerobic counts (TAC), total coliform counts (TCC), and generic Escherichia coli counts (ECC) on Petrifilm plates and to determine the prevalence of Salmonella spp., Listeria monocytogenes, and E. coli O157:H7 using standard enrichment techniques. Escherichia coli and L. monocytogenes strains were tested for various factors associated with their virulence by using colony hybridization and polymerase chain reaction (PCR), respectively. Antimicrobial susceptibility was determined for each isolate that was potentially pathogenic to humans by using the disk-diffusion method. Mean values for TAC, TCC, and ECC were 2.18, 0.16, and 0.06 log10 CFU/cm2, respectively, before pasteurization; 1.17, 0.03, and 0.01 log10 CFU/cm2 after pasteurization; and 0.89, 0.02, and 0.01 log10 CFU/cm2 after chilling. Prevalence of L. monocytogenes, Salmonella spp., and E. coli O157:H7 on carcasses was 0.8%, 0.0%, and 0.0%, respectively, before pasteurization; 2.6%, 0.0%, and 0.0% after pasteurization; and 3.1%, 0.1%, and 0.0% after chilling. The prevalence of E. coli containing > or = 1 virulence gene was 14.7%. More specifically, 11.88% of the isolates obtained before pasteurization, 22.2% obtained after pasteurization, and 31.2% obtained after chilling had virulence genes. All L. monocytogenes isolates tested positive for the presence of 3 major virulence factors (hlyA, inlB, and plcB). Antibiograms showed that certain isolates were susceptible to all antibiotics, some showed an intermediate sensitivity, and others were multiresistant. Overall, these results suggest that steam pasteurization is an effective means of improving safety quality of beef carcasses. However, pasteurization may indirectly contribute to the growth of some pathogenic microorganisms, such as L. monocytogenes.     

Characteristics of lambs fed concentrates or grazed on ryegrass to traditional or heavy slaughter weights. II. Wholesale cuts and tissue accretion

Targhee x Hampshire lambs (average BW 24 +/- 1 kg) were used to determine the effect of finishing on concentrate or by grazing ryegrass forage on slaughter weights of 52 kg (N) or 77 kg (H) on tissue accretion and lamb wholesale cutout. When fed to similar slaughter weights, the wholesale cuts of concentrate-fed lambs were heavier (P < 0.05) than the same cuts from forage-fed lambs; however, when expressed as a percentage of side weight, carcasses of forage-fed lambs had a higher (P < 0.001) percentage of leg than concentrate-fed lambs. Increasing slaughter weight from 52 to 77 kg resulted in a 1-kg increase in loin weight for lambs finished on concentrate and a 0.60-kg increase for lambs finished on forage (diet x slaughter weight, P < 0.03); however, the increased loin weight for lambs finished on concentrate was due largely to increased fat deposition. For lambs slaughtered at 77 kg, those finished on forage had more lean mass in the leg, loin, rack, and shoulder than those finished on concentrate, but lean mass in these cuts did not differ between diets for lambs slaughtered at 52 kg (diet x slaughter weight, P < 0.01). At the normal slaughter weight (52 kg), concentrate-fed lambs had 50% more dissectible fat than forage-fed lambs, whereas at the heavy slaughter weight, a 79% greater amount of dissectible fat was observed for concentrate- vs. forage-fed lambs (diet x slaughter weight, P < 0.001). Lean and fat accretion rates were higher (P < 0.001) for concentrate-fed lambs than for forage-fed lambs. The lean-to-fat ratio of forage-fed lambs was higher (P < 0.001) than that of concentrate-fed lambs; however, forage finishing decreased accretion rates of all tissues compared with concentrate feeding, and these differences between forage and concentrate feeding were magnified at heavier slaughter weights.     

Slaughter value, meat quality, creatine kinase activity and cortisol levels in the blood serum of growing-finishing pigs slaughtered immediately after transport and after a rest period

The experimental materials comprised 44 hybrid [female (Polish Large White x Polish Landrace) x male Duroc] growing-finishing pigs. The animals were randomly divided into two groups: 24 pigs were slaughtered immediately after transport and 20 pigs were slaughtered after a 24-hour rest period in the lairage. The meat content of pork carcasses, carcass dressing percentage, the proximate chemical composition, physicochemical and sensory properties of meat and shear force values were determined. Serum creatine kinase activity and cortisol levels were determined in blood samples collected before transport and during carcass bleeding. Pigs slaughtered immediately after transport, compared with those slaughtered after a 24-hour rest period, were characterized by a higher meat content of the carcass and a higher carcass dressing percentage. Pre-slaughter handling had no effect on pork quality. The incidence of normal-quality meat, partially PSE (pale, soft, exudative) meat and PSE meat was similar in both groups. Chemical analysis showed that the content of dry matter, total protein, fat and minerals in meat was comparable in both groups. As regards the functional properties of the pork, samples from the carcasses of pigs that had rested before slaughter had a higher contribution of the red color component. Meat from pigs slaughtered immediately after transport had more desirable sensory properties. Pre-slaughter resting had a significant effect on those analyzed physiological parameters which were found to be good indicators of pre-slaughter stress. Serum creatine kinase activity and cortisol levels were higher in blood samples collected after transport (during carcass bleeding) than in samples collected before transport, pointing to a strong stress response of animals to pre-slaughter treatment. The decrease in serum cortisol levels in blood samples collected during bleeding from the carcasses of pigs slaughtered after a 24-hour rest period, compared with samples collected from animals slaughtered immediately after transport, suggests that rest before slaughter alleviated stress induced by pre-slaughter handling operations.     

Distribution and genetic characterization of porcine Campylobacter coli isolates

The aim of this study was to evaluate the impact of the slaughter process on the Campylobacter (C.) coli prevalence on pig carcasses and finally pork. To detect C. spp., faecal samples, organ samples and surfaces of slaughter pigs were sampled. Additionally, various abattoir surfaces (n=208) and 227 pork and minced meat samples were included in our study.Whereas a high C. spp. prevalence (64.0%) was detectable in the faeces of slaughter pigs (all isolates were identified as C. coli), low detection rates were observed on pig carcasses after the slaughter process before the chilling period (21.1%).The impact of chilling reduced the detection rate of C spp. on pig carcasses even further to 0.8%. Only C. jejuni strains were isolated after the chilling process. Chilling and the associated drying of the skin are responsible for that massive reduction of C. spp prevalence. Significantly more C. spp. were isolated from livers compared to the corresponding carcasses. Only 5 out of 208 swab samples from different surfaces of the abattoir were C. coli positive. Bacteriological investigation could not detect any C. spp. strains from pork and minced pork meat.The low detection rates at the end of the slaughter and processing line indicate that pork may only play a minor role in the transmission of C. coli infections to humans. By genotyping C. coli-isolates from selected animals we were able to demonstrate three possible ways of contamination of the slaughter carcass surface. Genetically highly related strains were detectable on carcass surfaces of consecutively slaughtered animals. Faecal isolates and isolates from the carcass surface showed occasional high similarities. C. coli-genotypes from tonsils and genotypes from the corresponding slaughter carcasses formed a close cluster.     

A simulation model for studying the role of pre-slaughter factors on the exposure of beef carcasses to human microbial hazards.

A Monte Carlo simulation model was constructed for assessing the quantity of microbial hazards deposited on cattle carcasses under different pre-slaughter management regimens. The model permits comparison of industry-wide and abattoir-based mitigation strategies and is suitable for studying pathogens such as Escherichia coli O157:H7 and Salmonella spp. Simulations are based on a hierarchical model structure that mimics important aspects of the cattle population prior to slaughter. Stochastic inputs were included so that uncertainty about important input assumptions (such as prevalence of a human pathogen in the live cattle-population) would be reflected in model output. Control options were built into the model to assess the benefit of having prior knowledge of animal or herd-of-origin pathogen status (obtained from the use of a diagnostic test). Similarly, a facility was included for assessing the benefit of re-ordering the slaughter sequence based on the extent of external faecal contamination. Model outputs were designed to evaluate the performance of an abattoir in a 1-day period and included outcomes such as the proportion of carcasses contaminated with a pathogen, the daily mean and selected percentiles of pathogen counts per carcass, and the position of the first infected animal in the slaughter run. A measure of the time rate of introduction of pathogen into the abattoir was provided by assessing the median, 5th percentile, and 95th percentile cumulative pathogen counts at 10 equidistant points within the slaughter run. Outputs can be graphically displayed as frequency distributions, probability densities, cumulative distributions or x-y plots. The model shows promise as an inexpensive method for evaluating pathogen control strategies such as those forming part of a Hazard Analysis and Critical Control Point (HACCP) system.     

Shedding of food-borne pathogens and microbiological carcass contamination in rabbits at slaughter

To obtain microbiological data from rabbits at slaughter, 500 fecal samples and 500 carcasses samples were examined. All samples tested negative for Listeria and Salmonella. Campylobacter were detected in two fecal samples. Of the 500 fecal samples, 45.8% tested positive for eae (intimin), 1.2% for stx (Shiga toxin), and 1.8% for both eae and stx. By colony hybridization, 56 eae positive Escherichia coli strains were isolated. Among them, 27 strains (48.2%) were of the serotypes O178:H7 and O153:H7, whereas 15 strains (26.8%) belonged to a serogroup that has not yet been described (O(CB10681):H7). All strains possessed intimin beta1 and the translocated intimin receptor (tir) capable of being tyrosine phosphorylated. None of the strains harbored the genes for Shiga toxins, EAST1 (astA), bundlin (bfpA), or the EAF plasmid. Slaughter rabbits therefore constitute a reservoir for certain atypical enteropathogenic Escherichia coli. On rabbit carcasses, average total bacterial counts accounted for 3.3 log CFU cm(-2). Enterobacteriaceae and coagulase positive staphylococci (CPS) were detected on 118 (23.6%) and 153 (30.6%) carcasses, respectively. Enterobacteriaceae and CPS counts of positive samples were mainly <1.5 log CFU cm(-2). Among 153 selected CPS isolates, 98.7% were identified as Staphylococcus aureus. None of the 151 isolated strains harbored the gene for methicillin resistance (mecA). Genes for staphylococcal enterotoxins (SE) were detected in 102 strains. The combinations of seg and sei (53 strains) and sed, seg, sei, and sej (27 strains) dominated.     

Occurrences of thermophilic <Emphasis Type="Italic">Campylobacter</Emphasis> in cattle slaughtered at Morogoro municipal abattoir,Tanzania

An investigation was conducted in Morogoro municipality to assess the likelihood of slaughter cattle posing public health risk of contaminating carcasses with thermophilic Campylobacter. Butchers and meat shopkeepers were interviewed on source of slaughter cattle, method of animal and carcass transportation, carcass dressing, meat storage facilities, access to clean water and availability of food hygiene practices. Faecal samples were collected from 107 slaughter cattle and after slaughter; four different parts of dressed carcasses (i.e. from ham, neck, pelvis and thigh muscles) were also sampled. In addition 107 cattle meat samples for Campylobacter culture were collected in different meat shops. The samples were subjected to standard bacteriological examination using Skirrows protocol. It was found that cattle slaughter, dressing and meat handling in meatshops was done under unhygienic condition. Thermophilic Campylobacter prevalence in slaughter cattle was 5.6% while contamination rate of dressed carcasses and cattle meat at shops was 9.3% and 1.9%, respectively. The majority of thermophilic Campylobacter isolated were C. jejuni (88.9%) while C. coli was isolated at 11.1%. Findings of this study suggest possibility of humans acquiring zoonotic Campylobacter infections from cattle meat particularly when meat preparation and processing is not done properly. More work is required to establish the magnitude of zoonotic enteric Campylobacteriosis in humans and epidemiological role of cattle and other animals in the study area.     

Effects of boning method and postmortem aging on meat quality characteristics of pork loin

This work investigated the effects of boning method and postmortem aging on pork loin color, shearing value and sensory attributes. Two experiments were assigned. In Experiment I, 30 Chinese native black pigs were slaughtered and their carcasses were divided into three groups: (i) hot-boning: carcasses were fabricated within 45 min postmortem just after dressing; (ii) cold boning at 24 h: carcasses were fabricated after chilling at 0°C for 24 h; (iii) cold boning at 36 h: carcasses were fabricated after chilling at 0°C for 36 h. In Experiment II, right sides of the second group in Experiment I were used and primal cuts were vacuum packed and aged for 1 day, 8 days and 16 days. Pork loins ( Longissimus lumborum ) were used for color measurement, shearing test, and sensory evaluation. Among three boning methods, cold-boning at 36 h postmortem had the advantages of giving muscles a better color, the lowest cooking loss and cooked shearing value, and the highest sensory tenderness, juiciness, flavor and overall liking. Postmortem aging could improve pork quality characteristics, but it is not the fact that the longer aging time is, the better pork quality would be. Eight days may be enough to obtain an acceptable sensory attribute. These results are meaningful for pork processing and pork consumption.     

A survey of the hygienic quality of beef and pork carcasses in Norway

The bacteriological quality of beef and pig carcasses was assessed at 9 Norwegian abattoirs by sampling 10 carcasses at multiple sites on each of several visits. On beef carcasses the following sites consistently carried higher numbers of bacteria: the Brisket, the Fore-ribs, the Flank groin, and the Round medial. There was no evidence that beef slaughter and dressing in the hanging position was superior to methods where the carcass was lying until the hide puller. On pork carcasses the Cheek, and the Abdomen lateral surface (belly) were most heavily contaminated. The hygienic quality of pork carcasses in abattoirs where singeing was a separate step tended to be better than where a combined singeing and dehairing machine was used.This survey suggests that bacteriological monitoring of slaughter at this level of sampling and visiting is able to detect consistently poor hygienic practices.Where direct comparisons with data from other countries could be made, the present investigation indicates that the bacterial counts on Norwegian beef and pork carcasses are of the same order or better.Key words: abattoir, slaughter, beef, pork, hygiene     

Influence of body condition score on carcass characteristics and subprimal yield from cull beef cows.

Mature beef cows (n = 83) were slaughtered to measure the influence of body condition score (BCS) on carcass characteristics and subprimal yields. All cows were weighed and assigned BCS, based on a 9-point scale, 24 h before slaughter. Cows were slaughtered, and, after a 48-h chilling period, quality and yield grade data were collected on the left side of each carcass. The right side was quartered, fabricated into primal cuts, and weighed. Each primal cut was further processed into boneless subprimal cuts, minor cuts, lean trim, fat, and bone. Cuts were progressively trimmed to 6.4 and 0 mm of external and visible seam fat. Weights were recorded at all stages of fabrication, and subprimal yields were calculated as a percentage of the chilled carcass weight. Live weight, carcass weight, dressing percentage, fat thickness, longissimus muscle area, muscle:bone ratio, and numerical yield grade increased linearly (P = .0001) and predicted cutability and actual muscle-to-fat ratio decreased linearly (P = .0001) as BCS increased from 2 to 8. Carcasses from BCS-8 cows had the most (P<.05) marbling. The percentage of carcasses grading U.S. Utility, or higher, was 16.7, 20.0, 63.6, 43.3, 73.3, 100.0, and 100.0% for cows assigned a BCS of 2, 3, 4, 5, 6, 7, and 8, respectively. At 6.4 mm of fat trim, carcasses from BCS-5 cows had higher (P<.05) shoulder clod yields than carcasses from cows having a BCS of 6, 7, and 8. Carcasses of BCS-2 cows had lower (P<.05) strip loin yields than carcasses from BCS-3, 4, 5, 6, and 7 cows. Top sirloin butt yields were higher (P<.05) for carcasses of BCS-2, 3, 4, and 5 cows than those of BCS-6, 7, or 8 cows. Carcasses from BCS-7 and 8 cows had lower (P<.05) tenderloin and inside round yields than carcasses of BCS-5, or less, cows. At both fat-trim levels, carcasses from BCS-5 cows had higher (P<.05) eye of round yields than cows assigned BCS of 2, 7, or 8. When subprimal cuts were trimmed to 6.4 mm of visible fat, carcasses from BCS-5 cows had higher (P<.05) total lean product yields than cows assigned a BCS of 2, 4, 7, and 8. Regardless of fat trim, total fat yields increased (P = .0001) and total bone yields decreased (P = .0001) linearly as BCS increased from 2 to 8. Although carcasses from BCS-5 and 6 cows had the highest yields of lean product, cattle producers and packers may benefit most by marketing and(or) purchasing BCS-6 cows because a higher percentage of their carcasses had quality characteristics deemed desirable for fabrication into boneless subprimal cuts.     

Effects of slaughter weight and carcass electrical stimulation on the quality and palatability of beef from young purebred bulls

Seventy-eight purebred Angus and Brahman bulls (10 to 18 mo at slaughter) were used to determine the effects of slaughter weight (60, 80, 90 or 100% of the average mature-cow weight for the respective breed) and carcass electrical stimulation (500 V, 20 2-s impulses on the right side) on carcass and meat characteristics. Angus bulls grazed summer forage (millet) after weaning, while Brahman bulls were fed to stimulate gains achieved on forage by Angus bulls. Bulls were then placed in the feedlot for finishing to their designated slaughter weight (293, 381, 412 and 463 kg for Angus and 316, 420, 463 and 516 kg for Brahman). Coarse dark band formation and lean color problems normally associated with bullock carcasses were either eliminated or reduced by stimulation. Increasing slaughter weight from 60 to 90% was associated with an increase in panel tenderness scores for loin steaks. However, increasing slaughter weight from 90 to 100% little change was detected. On the other hand, shear values for loin steaks decreased with increasing slaughter weight. Stimulation increased the tenderness of loin steaks as determined by both panel scores and shear values, and of bottom round steaks (shear-force values). The data from this study suggest that meat from the bulls slaughtered at lighter weights was generally tough, but was improved when bulls were fed to heavier, yet acceptable weights. This research encourages implementation of electrical stimulation on carcasses from young bulls to improve quality-indicating factors.     

The effects of two shipping treatments on the carcass characteristics of bulls implanted with zeranol and unimplanted steers

A total of 144 male crossbred calves were allocated to four management treatments (bulls; steers; bulls implanted with zeranol at 100 d of age and re-implanted at 69, 93 and 56 d thereafter; bulls implanted with zeranol at 168 d of age and re-implanted at 93 and 56 d thereafter), and two pre-slaughter shipping treatments (minimum pre-slaughter stress with cattle shipped and slaughtered within 4 h of leaving the feedlot pen; moderate pre-slaughter stress with cattle mixed, trucked 160 km and slaughtered up to 24 h of leaving the feedlot pen) in a 4 X 2 factorial arrangement. Management treatment had no significant effect on carcass pH (45 min), carcass muscle temperature (45 min), or peak shear-force of cooked longissimus muscle. Steers had significantly lower dressing percentage, warm-carcass weight, hide weight and carcass-lean content, but higher marbling score, fat thickness and intramuscular-fat content than all treatments with bulls. Minimum pre-slaughter stress resulted in significantly lower dressing percentage, warm-carcass weight, and carcass pH (45 min), but generally had no effect on carcass tissue-yield measurements compared with the moderate stress treatment. Implanted bulls produced carcasses with significantly darker meat, higher 24-h pH and lower meat expressible juice than bulls and castrates for the moderate pre-slaughter stress treatment. These results provide evidence that zeranol implantation in bulls had a minor influence on carcass characteristics, and did not reduce the incidence of dark-cutting carcasses in young bulls subjected to moderate pre-slaughter shipping stress.     

The effectiveness of in‐plant chlorination in poultry processing

1. Sampling carcasses after plucking or after the post‐evisceration spray‐wash showed that 10 or 20 ppm available chlorine in the processing‐plant water supply caused little reduction in carcass contamination.

2. When 20 ppm chlorine was used in the water supply to parts of the processing‐plant other than the mechanical immersion chilling system, counts of faecal and spoilage bacteria from carcasses were reduced approximately 10‐fold after passage through the chilling system; bacterial numbers were correspondingly decreased in the chiller water due to a carry‐over of chlorine from the final spray‐washer.

3. Artificial contamination of carcasses with a readily identifiable strain of Escherichia coli confirmed the occurrence of cross‐contamination during plucking and evisceration; in‐plant chlorination reduced neither the proportion of carcasses contaminated nor the numbers of organisms transferred at these stages.

4. In most cases the chlorine‐resistance of poultry spoilage pseudo‐monads was greater than that of E. coli; hence in‐plant chlorination is to be recommended for processing‐plant water supplies which carry such spoilage organisms.