The production and microbiological status of skin-on sheep carcasses

There is a demand by certain ethnic consumer groups in the United Kingdom for skin-on, singed carcasses, primarily from older sheep, but their production is illegal under current EU legislation. The aim of this study was to devise a protocol to produce carcasses having the desired ‘smoked’ colour and odour and an acceptable microbiology. A successful result could form the basis of a case to revise the legislation. Three key steps in the selected procedure were carcass singeing using specially designed gas burner equipment, pressure washing to clean the carcass and then evisceration. It was shown that a second heat application, termed ‘toasting’, if applied after evisceration, significantly (P < 0.001) reduced Enterobacteriaceae and TVC counts on carcasses before chilling. Microbiological quality was also improved when toasting was the final step, following carcass splitting and inspection. Carcasses produced in this way had significantly (P < 0.001) lower Enterobacteriaceae and TVC counts before chilling than conventionally dressed sheep carcasses produced in the same abattoir.     

Influence of food withdrawal at various times preslaughter on carcass yield and meat quality in sheep

Castrated male crossbred lambs were fed a complete pelleted diet ad libitum for 4 weeks prior to slaughter at a liveweight of about 32 kg. Forty lambs were killed directly off feed and forty each after 24, 48 and 72 h from food withdrawal. They had access to water at all times. Fasting had a significant effect on the weights of all body components examined except the combined fleece and feet. Liveweight was lost slightly more rapidly over the initial 24 h after food withdrawal, and this was attributable mainly to a 20% decrease in the weight of the gut contents. The overall rate of liveweight loss between 0 and 72 h was 0.14% h^?1. The corresponding loss of carcass weight was 0.085% h^?1, some reduction in yield being evident by 24 h of fast although a significant effect was seen only after 48 h. Liver weight was lost most rapidly (0.69% h^?1) over the initial 24 h but continued to be lost throughout fasting. Associated with the initial decrease in liver weight was a rapid loss of glycogen to very low levels by 24 h after food withdrawal. Fasting also reduced muscle glycogen concentrations but had no large or consistent effects on ultimate pH, reflectance or water-holding capacity.     

Inspection of lymph nodes for caseous lymphadenitis and its effect on the density of microbes on sheep carcasses

This study aimed to measure the amount of microbial contamination caused by inspecting the lymph nodes of adult sheep carcasses for caseous lymphadenitis (CLA). Surface swabs from carcasses pre-inspection (N=296) and post-inspection (N=296) were obtained for enumeration of indicator organisms at three commercial abattoirs. At the scapular site, inspection doubled the probability of detecting E. coli (Pr before=0.35, Pr after=0.67) and increased the expected count of E. coli from 2cfu/cm(2) to 13cfu/cm(2). Inspection at the rump site increased the probability of detecting E. coli by 1.1 times (Pr before=0.84, Pr after=0.93) and increased the expected count from 32cfu/cm(2) to 45cfu/cm(2). Effects were also observed for Enterobacteriaceae and total viable count. The findings show that routine inspection of adult sheep carcasses for CLA has a detrimental impact on carcass microbiological traits.     

The effect of hot-water immersions on the appearance and microbiological quality of skin-on chicken-breast pieces

Summary Immersion in hot water is one of many potential methods for reducing levels of pathogenic bacteria on the surface of poultry meat. However, if the meat is to be sold in the raw state reductions in microbiological numbers need to be achieved without changing the appearance of the meat. Samples of vacuum-packed skin-on chicken breast were immersed in hot water for a range of temperatures and times. Samples were then water cooled to arrest further heating. The final appearance of the samples was assessed visually and instrumentally with a chroma meter. Surface and internal temperatures were also measured. From this series of initial experiments a range of maximum temperature–time treatments were identified that would not cause unacceptable changes to surface appearance. Microbiological tests were then conducted on samples inoculated with a nalidixic acid resistant strain of Escherichia coli serotype O80 subjected to these treatments. The results showed that determining changes to the appearance of skin from samples by using a chroma meter was difficult. The changes caused to the samples by heat treatment were initially textural rather than colourimetric and thus could be identified visually but not instrumentally with a chroma meter. Visual changes were found for immersion times greater than 120 s at 50 °C, 60 s at 60 °C, 9 s at 70 °C, 6 s at 80 °C, 2 s at 90 °C and 1 s at 100 °C. The average temperatures measured on the surface after 2 s immersion at 90 °C and after 60 s at 60 °C were 20.5 °C and 54.8 °C, respectively. No reductions in counts of E. coli serotype O80 were measured on samples treated under these conditions. The results indicate that there is no immersion heat treatment (below 90 °C) capable of reducing contamination with E. coli , or similar thermotolerant microorganisms, on poultry without causing adverse changes in the product.     

Prevalence and risk factors for bruises in Chilean bovine carcasses

Records of cattle slaughtered at two Chilean slaughterhouses (SLH1 and SLH2) were used to determine prevalence and risk factors for carcasses with bruises. Bruise prevalence amounted to 12.3% but differed between slaughterhouses (20.8% for SLH1 and 8.6% for SLH2 respectively). Bruise severity grade 1 (mild) was most frequently recorded. The type of the animal, source of animal, the level of fat cover and lairage time were associated with the presence of bruises. Older categories of animals and animals that pass through a market before being moved to the slaughterhouse are more prone to show bruises. The results also indicate that under the reported Chilean circumstances animals that have longer lairage times (over 12 h) have a significantly reduced risk for bruises, except for oxen. Presence of bruises is also significantly associated with increased carcass pH values.     

Sustainable sheep production and consumer preference trends: Compatibilities,contradictions, and unresolved dilemmas

There are increasing concerns of society towards the consumption of animal products which have been produced and transformed in a sustainable manner. This trend influences consumer purchasing decision making, particularly in developed countries. On the other hand, in the next years, the pressure to increase the volume and efficiency of meat production will be much higher to cope with the expected unsatisfied demand. At least in part, current and future technologies could contribute to solve this challenge. However, the use of some of these innovations could have a negative effect on consumer preferences. There is no consensus in our society about this dilemma. The objective of this paper is to review the scientific evidence related to these topics and to analyze and discuss the effect of some of the extrinsic and intrinsic factors linked with the sheep industry which could affect the acceptability of lamb meat by consumers.     

羊胎酶的水解工艺条件

研究了适用于羊胎水解的蛋白酶及其最适的酶解条件，研究结果如下：以水解度和氮收率为指标，通过中性蛋白酶，胃蛋白酶，胰酶和木瓜蛋白酶4种蛋白酶对羊胎蛋白质水解效率的比较，选择胰酶为水解羊胎的最适酶。     

The microbiological conditions of carcasses from large game animals in Italy

This study investigates the microbiological conditions of large game animal carcasses following evisceration. Carcasses of animals (N=291) hunted in the Upper Susa Valley (Italian Alps) were analysed for pH, Aerobic Viable Count (AVC), Enterobacteriaceae, Yersinia spp., Listeria monocytogenes and Salmonella spp. After shooting, evisceration occurred within 60 min in 90.7% of animals and sampling within 90 min in 88.3% of animals. Mean pH values (5.97: ruminants; 5.77: wild boar) were similar to those of regularly slaughtered domestic species. AVC values were highest in animals shot in the abdomen. Within species, AVC and Enterobacteriaceae values did not differ across different shooting-evisceration/sampling times. However, these counts exceeded 5 and 2.5 log, respectively, in 18% of wild boar and 39% of ruminants; the highest values were detected in wild boar. No pathogens were detected in any species. These results reveal inadequate hygiene in game meat handling/harvesting, implicating the need for improved practices.     

Virtual dissection of pig carcasses

This paper proposes the use of computed tomography (CT) as a reference method for estimating the lean meat percentage (LMP) of pig carcasses. The current reference is manual dissection which has a limited accuracy due to variability between butchers. A contextual Bayesian classification scheme is applied to classify volume elements of full body CT-scans of pig carcasses into three tissue types. A linear model describes the relation between voxels and the full weight of the half carcass, which can be determined more accurately than that of the lean meat content. Two hundred and ninety-nine half pig carcasses were weighed and CT-scanned. The explained variance of the model was R²=0.9994 with a root-mean-squared error of prediction of 83.6 g. Applying this method as a reference will ensure a more robust calibration of sensors for measuring the LMP, which is less prone to variation induced by manual intervention.     

烧毛灭火及水洗方法对冷轧堆前处理的影响

在冷轧堆前处理过程中,为提高退煮效果,除选择适合的助剂及其浓度,控制工艺时间等因素外,还应特别注意其配套工艺。采用不同的烧毛灭火方式及水洗设备进行冷轧堆前处理,对织物的毛效及棉籽壳的去除有很大影响。     

食品微生物检验及实验室质量控制

食品是人类赖以生存的基础,食品微生物检验对于确保食品安全具有重要作用。食品微生物检测是保证食品质量安全的重要手段,随着人类生活质量不断提高,食品安全已经成为社会各界关注的重点。微生物检测工作的科学开展能够有效提升食品安全,对我国现代食品行业发展具有不可或缺的重要价值。本文主要介绍了食品微生物检验的主要内容及特点、检测技术及方法、食品微生物实验室质量控制措施等,为本行业工作人员提供可靠的理论依据。     

Sampling methods for microbiological analysis of red meat and poultry carcasses

Microbiological analysis of carcasses at slaughterhouses is required in the European Union for evaluating the hygienic performance of carcass production processes as required for effective hazard analysis critical control point implementation. The European Union microbial performance standards refer exclusively to the excision method, even though swabbing using the wet/dry technique is also permitted when correlation between both destructive and nondestructive methods can be established. For practical and economic reasons, the swab technique is the most extensively used carcass surface-sampling method. The main characteristics, advantages, and limitations of the common excision and swabbing methods are described here.     

Physicochemical and microbiological changes in irradiated fresh pork loins

The effect of γ-irradiation on the physicochemical and microbiological properties of fresh pork was studied. Radiation treatments were carried out under air on fresh pork loins at doses of 2, 4 and 8 kGy and the loins were evaluated for deamidation, solubility, sulphydryl content and surface hydrophobicity. Deamidation was significantly (p0.05) affected by the treatment with 98% deamidation at a dose of 8 kGy. No significant changes (p > 0.05) were noted in sulphydryl content under the same conditions. The increase in deamidation resulted in a decrease in hydrophobicity and an increase in protein solubility. γ-irradiation also reduced the number of microorganisms in the meat. Mesophiles were more resistant to the irradiation treatment than psychrotrophs and Pseudomonas. All irradiated pork samples (1 or 3 kGy) had a bacterial count lower that 10⁷ CFU/g after 15 days of storage. A minimal dose of 1 kGy was sufficient to increase the shelf life of fresh pork loins although variations in initial pork contamination was found to be the determining factor accounting for the effectiveness of the treatment.     

Quantitative investigation of the effects of chemical decontamination procedures on the microbiological status of broiler carcasses during processing

The effects of elevated chlorine concentrations (25 ppm) added to water in the final carcass washing equipment on total viable counts (TVCs 22 degrees C) and Escherichia coli and Enterobacteriaceae levels on poultry carcasses were investigated. Mean TVC counts on neck skin samples were significantly reduced when pre-evisceration and postwash samples were compared with log10 4.98 to 4.52 CFU/g recovered, respectively (P < or = 0.05). No significant reductions in TVC counts were observed in control samples at corresponding sampling points subjected to wash water containing 1 to 2 ppm chlorine. E. coli and Enterobacteriaceae counts were not significantly altered following final carcass washing in the processing plant. A second trial assessed the microbial decontamination capabilities of sodium triphosphate (TSP) on broiler carcasses. Neck skin samples from carcasses were obtained before final washing (control), following a 15-s dip in potable water and after dipping in a 10% TSP solution (pH 12) for 15 s. Reductions in E. coli and Enterobacteriaceae counts were all statistically significant for both water and TSP-treated samples when compared with corresponding controls (P < or = 0.01). The TSP treatment resulted in higher reductions of log10 1.95 and 1.86/g for E. coli and Enterobacteriaceae, respectively. In contrast, reductions of log10 0.37 and 0.3 l/g were observed for E. coli and Enterobacteriaceae counts when water-dipped carcasses were compared with corresponding controls. Significantly, Salmonella was not detected in any of the TSP-treated carcasses, while log10 1.92 and 1.04/g were found in control and water-dipped samples, respectively. Thermophilic Campylobacter counts were significantly lower in both treatment groups when compared with corresponding controlsresulting in log10 0.55 and 1.71/g reductions for water- and TSP-dipped carcasses, respectively (P < or = 0.01).     

Experimental comparison of excision and swabbing microbiological sampling methods for carcasses

Bovine sides, ovine carcasses, and porcine carcasses were individually inoculated by dipping in various suspensions of a marker organism (Escherichia coli K-12 or Pseudomonas fluorescens), alone or in combination with two meat-derived bacterial strains, and were sampled by two standard methods: cotton wet-dry swabbing and excision. The samples were examined for bacterial counts on plate count agar (PCA plate counts) and on violet red brilliant green agar (VRBGA plate counts) by standard International Organization for Standardization methods. Average bacterial recoveries by swabbing, expressed as a percentage of the appropriate recoveries achieved by excision, varied widely (2 to 100%). Several factors that potentially contributed to relatively low and highly variable bacterial recoveries obtained by swabbing were investigated in separate experiments. Neither the difference in size of the swabbed area (10, 50, or 100 cm2 on beef carcasses) nor the difference in time of swabbing (20 or 60 min after inoculation of pig carcasses) had a significant effect on the swabbing recoveries of the marker organism used. In an experiment with swabs preinoculated with the marker organism and then used for carcass swabbing, on average, 12% of total bacterial load was transferred inversely (i.e., from the swab to the carcass during the standard swabbing procedure). In another experiment, on average, 14% of total bacterial load was not released from the swab into the diluent during standard swab homogenization. Use of custom-made swabs with abrasive butts, around which metal pieces of pan scourers were wound, markedly increased PCA plate count recoveries from noninoculated lamb carcasses at commercial abattoirs compared with cotton swabs. In spite of the observed inferiority of the cotton wet-dry swabbing method compared with the excision method for bacterial recovery, the former is clearly preferred by the meat industry because it does not damage the carcass. Therefore, further large-scale evaluation of the two carcass sampling methods has been undertaken under commercial conditions and reported separately.     

The microbiology of sheep carcasses processed in a modern Indian abattoir

A study has been conducted on the microbiology of sheep carcasses processed in a modern abattoir. The data revealed that careful handling at the different stages of processing of sheep reduced the level of microbial contamination of carcasses. Processing steps such as evisceration and washing did not increase the microbial counts on the carcass surface. Sources of microbial contamination in the abattoir were examined. It was observed that skin, floor washings, intestinal contents and gambrels were the major sources of microbial contamination. Seasonality did not have any effect on the microbial contamination of carcasses. The study revealed that total plate counts in 86·6% of the carcasses ranged between 3·0–4·9log/cm². The counts of coliforms, staphylococci, enterococci and psychrotrophs were low. Pathogens such as Salmonella were not detected. The microbial counts were well within the generally acceptable levels. These findings demonstrated hygienic handling of carcasses. Shoulder and neck are the critical points for microbiological sampling as these sites showed higher microbial counts. Micrococcus and Staphylococcus predominated among microorganisms associated with carcasses. It was noted that differences occurred in microbial types of carcasses processed in tropical and temperate climates. The data generated in a model facility procided useful information for improving meat handling practices.     

Visible contamination on animals and carcasses and the microbiological condition of meat

It is generally assumed that preventing visible contamination of or removing visible contamination from carcasses will enhance the microbiological safety of meat. Visible contamination of carcasses can be reduced by washing or otherwise cleaning animals before slaughter, by dehairing hides before carcasses are skinned or dressed with the skin on, or by performing skinning and eviscerating operations in manners that avoid the transfer of filth from the hide to the meat or the spillage of gut contents. Visible contamination can be removed by washing, trimming, or vacuuming carcasses. The available data appear to indicate that, of the various actions that can be taken to obtain carcasses that are free of visible contamination, only minimizing the visible contamination of meat during skinning and eviscerating operations may also ensure a degree of control over the microbiological contamination of meat. It might be preferable for visible contamination to be controlled largely by superior skinning and eviscerating practices rather than by animal or carcass cleaning treatments, which may not prevent the depositing of bacteria on or the removal of substantial numbers of bacteria from carcasses.     

猪胴体预冷过程中雾化增湿与喷淋对干耗的影响差异性研究

本研究对比了雾化增湿与雾化喷淋两种方式对猪胴体预冷干耗的影响。采用超声雾化加湿器来增加预冷环境湿度方式以及气液两相流间歇雾化喷淋的方式分别对猪胴体样品进行预冷处理,以直接冷却猪胴体样品为对照组。实验结果表明:雾化增湿组样品最终平均干耗为1.442%,经14 h雾化喷淋处理的各样品继续冷却至24 h后测得最终平均干耗为1.066%,对照组实验样品最终平均干耗为2.914%。雾化喷淋冷却处理与雾化增湿冷却处理均可使猪胴体冷却速度加快(p<0.05)。雾化喷淋冷却处理与雾化增湿冷却处理均可有效缩短样品干耗达到峰值的时间(p<0.05),其达到峰值时间关系为:雾化喷淋组<雾化增湿组<对照组。雾化喷淋冷却处理与雾化增湿冷却处理均可显著降低猪胴体预冷干耗(p<0.05);雾化喷淋冷却处理比雾化增湿冷却处理降低干耗效果更为理想(p<0.05)。      

Intensive sheep and beef production from pasture — A New Zealand perspective of concerns,opportunities and challenges

This paper details current production trends for sheep and beef cattle production in New Zealand and gives some insight into the opportunities for improvement based on New Zealand research at Massey University. Further it outlines some of the challenges the industries face in the near future. The New Zealand climate favours pasture growth and this is the key to sheep and beef cattle production with over 95% of the diet being grazed pasture or crop. Exports are the focus of the industry with 95% of sheep meat and wool, and 80% of beef exported. There have been considerable gains in production over the last 20 years but there still remains a huge opportunity for further intensification through breeding sheep at an earlier age, increasing the weight of lambs weaned per ewe per year and improving beef production systems. These improvements need to occur within a framework of minimal environmental footprint and produce products that are in demand in the high end international markets.     

Determination of the lean meat percentage of pig carcasses using magnetic resonance imaging

The purpose of Workpackage 3 of the European Eupigclass project was to test indirect methods of measuring the lean meat percentage of a carcass that would be less costly, at least as accurate and more consistent than dissection. Magnetic resonance imaging was one of the three indirect methods tested to measure the lean meat weight and the lean meat percentage of pig carcasses, the other methods being X-ray CT and vision techniques. One hundred and twenty carcasses from three different genotypes and from both sexes were slaughtered. The left parts of the carcasses were fully dissected and the right parts were investigated with an indirect method using a 1.5T MRI system. The acquisition protocol was chosen to give an optimized contrast between fat and muscle tissues. Two different approaches, image segmentation and PLS regression, were used to extract information from the images. Automatic image segmentation was performed to quantify the volume of muscle in the images and gave a standard error of prediction using a linear regression with the dissection of the left half carcasses of 586 g and 1.10% for lean meat weight and lean meat percentage, respectively. PLS regression using the signal intensities histograms gave an estimation error of 465 g for lean meat weight. These results showed that MRI could be used in place of full dissection for authorizing and monitoring classification equipment of pig carcasses.