Decontamination of cattle hides prior to slaughter using washes with and without antimicrobial agents

Two trials were conducted to determine the efficacy of cattle wash treatments in reducing pathogens on hides of cattle before slaughter. In trial I, live cattle (n = 120) were washed in an automated, commercial cattle wash system with one of four treatments (single water wash, double water wash, water wash with 0.5% L-lactic acid, or water wash with 50 ppm chlorine). Samples were collected at three locations (brisket, belly, and inside round) pre- and posttreatment to evaluate the effectiveness of treatments on the reduction of aerobic plate counts, coliforms, Escherichia coli and the incidence of Salmonella. For all three locations, bacterial numbers increased from 0.1 to 0.8 log CFU/cm2 posttreatment. In trial II, hide samples were inoculated in the laboratory with 6.0 log CFU/cm2 of rifampicin-resistant Salmonella serotype Typhimurium. Hide wash treatments included higher concentrations of chlorine (100, 200, and 400 ppm) and L-lactic acid (2, 4, and 6%), as well as other antimicrobial agents such as ethanol (70, 80, and 90%), acetic acid (2, 4, and 6%), and Oxy-Sept 333 (0.5, 2, and 4%). Spray wash treatments with ethanol and 4 to 6% concentrations of lactic acid had greater (P < 0.05) mean log reductions than 2% solutions of acetic or lactic acid, as well as 100, 200, and 400 ppm chlorine and the control water wash treatment. Spray wash treatments with Oxy-Sept 333 and 100, 200, or 400 ppm chlorine were not effective (P > 0.05) in reducing Salmonella Typhimurium compared to the (control) distilled water spray wash treatment. Several effective cattle hide interventions were identified in a controlled laboratory setting, but the high concentrations required for effectiveness would likely present problems from an animal welfare standpoint.     

Pulsed-field gel electrophoresis characterization of Shiga toxin-producing Escherichia coli O157 from hides of cattle at slaughter

Contamination of the brisket areas of the hides of healthy adult cattle with Shiga toxin-producing Escherichia coli O157 at slaughter in England was studied. In total, 73 cattle consignments comprising 584 animals delivered to one abattoir over 3 days during 1 week in July 2001 were studied: 26 cattle consignments arriving on Monday, 32 consignments arriving on Wednesday, and 15 consignments arriving on Friday. Consignment sizes ranged from 1 to 23 animals, with a mean consignment size of 8. The hide of the first animal to be slaughtered in each consignment was sampled by using a sponge swab moistened with 0.85% saline to rub an unmeasured brisket (ventral) area (ca. 30 by 30 cm). The process of isolating E. coli O157 from the swabs consisted of enrichment, screening with immunoprecipitation assay kits, and immunomagnetic separation. E. coli O157 was found on 24 of 73 (32.9%) cattle hides examined, and 21 of these 24 isolates produced Shiga toxins. The 24 E. coli O157 isolates produced six different pulsed-field gel electrophoresis profiles, and 18 (75%) of the isolates were of one prevalent clone. The high prevalence of one E. coli O157 clone on the hides of cattle at slaughter could be due to a high prevalence of that clone on the 18 farms involved (not investigated in the current study), in the postfarm transport or lairage environments, or both. Since the lairage environment, but not the farm of origin or the postfarm transport vehicle, was a factor common to all 18 cattle consignments, it could have played an important role in spreading the prevalent E. coli O157 clone to the cattle hides. Lairage pen floors and the stunning box floor were identified as the most probable sites along the unloading-to-slaughter route at which the brisket areas of cattle hides could become contaminated.     

Treatment of cattle hides with Shellac solution to reduce hide-to-beef microbial transfer

The hide-to-beef microbial transfer-reducing effects of a novel Shellac treatment of hides (based on "on-hair immobilization" of microorganisms) were evaluated. In the hide-to-meat direct contact laboratory-based experiments, treatment of hides (of varying visual cleanliness) with Shellac produced significant microbial reductions on beef: up to 3.6 log(10) CFU/cm(2) of total viable count of bacteria (TVC), up to 2.5 log(10) CFU/cm(2) of Enterobacteriaceae (EC) and up to 1.7 log(10) CFU/cm(2) of generic Escherichia coli (GEC). In a small commercial abattoir under "bad-case" conditions (slaughtering dirty cattle, inadequate process hygiene), treatment of hides with Shellac produced significant microbial reductions on beef carcasses: 1.7 log(10) CFU/cm(2), 1.4 log(10) CFU/cm(2) and 1.3 log(10) CFU/cm(2) of TVC, EC and GEC, respectively. In both laboratory- and abattoir-based trials, TVC reductions on beef achieved by the Shellac hide treatment were superior to those achieved by the comparative sanitizer rinse-vacuum hide treatment, but reductions of EC and GEC did not differ significantly between the two hide treatments.     

牛皮和绵羊皮二氧化碳脱灰工艺的新探索

目前,世界上已经有许多制革企业将二氧化碳用于制革脱灰,由于这种脱灰方法耗费的时间略长一些,因     

Time to collapse following slaughter without stunning in cattle

Time to physical collapse was examined in 174 cattle which were restrained in the upright position and then released immediately from the restraint following the halal cut. The frequencies of swelling and false aneurysm in the cephalic and cardiac severed ends of the arteries were recorded. Fourteen percent of the cattle collapsed and stood up again before finally collapsing. The average time to final collapse for all the cattle was 20 s (sd ± 33). In 8% of the animals time to final collapse was ?60 s. Seventy-one percent of the cattle that took more than 75 s to collapse had false aneurysms in the cardiac ends of the severed carotid arteries. The frequency of swelling at the cephalic severed ends of the carotid arteries in 129 cattle was 7%. Failure to collapse within 60 s was associated with swelling of the cephalic ends of the carotid arteries.     

Synergistic effect of ozonated and electrolyzed water on the inactivation kinetics of Escherichia coli on goat meat

Ozonated and electrolyzed water have been reported to have bactericidal activities against most pathogenic and spoilage microorganisms associated with fresh meat and contact surfaces in meat processing facilities at room temperature. However, antimicrobial effects of these two treatments combined are not known. Therefore, the objective of this study was to evaluate the effectiveness of ozonated and electrolyzed water in combination for inactivating Escherichia coli K12 on goat meat. The combination of ozonated water and alkaline electrolyzed water resulted in higher log reductions (1.03 CFU/ml) compared to ozonated water alone (0.53 CFU/ml). Regression analysis performed using the GInaFiT tool showed that nonlinear Weibull models were more effective than log-linear models for describing the inactivation kinetics of E. coli K12 on goat meat.     

An evaluation of selected methods for the decontamination of cattle hides prior to skinning

The effectiveness of different decontamination treatments in reducing microbial loads on cattle hides was assessed. The 10-s hide treatments were conducted using a wet-and-dry vacuum cleaner filled with one of the liquids (heated to 50 °C) indicated below, followed or not by 10-min drying in the air. Also, the hide was clipped, followed or not by 10-s singeing using a hand-held blowtorch. Before and after each decontamination treatment, the hide was sampled (100 cm(2) areas) by a sponge-swabbing method to compare the total viable counts of bacteria (TVC). The largest bacterial reduction (P<0.001; 2.31log(10) cfu/cm(2)) was achieved by singeing of previously clipped hide. Treatment of hide with a food industry sanitizer solution (10% Betane Plus) resulted in significant reductions of 1.80 (P<0.001) and 1.98log(10) cfu/cm(2) (P<0.001) without and with subsequent drying, respectively. Treatment of hide with a food industry disinfectant (P3-Topactive DES) significantly reduced TVC by 0.97 (P<0.001) and 1.18log(10) cfu/cm(2) (P<0.001) without and with subsequent drying, respectively. Treatments of hide with water alone or with a food-safe detergent solution (Formula 963B), or hide clipping alone, did not produce significant decontamination effects. Since hide contamination is associated with microbial contamination of the carcasses, the results indicate that post-killing/pre-skinning hide decontamination (used alone, or in combination with carcass decontamination) has a potential to improve microbial meat safety. Nevertheless, further research is required to optimise the efficacy of these treatments in the reduction of specific pathogens under commercial conditions.     

肉牛屠宰加工研究

主要介绍肉牛产业现状和加工工艺,对生产工艺进行深入探讨,并针对肉牛常见的质量展开分析,提出了具体的解决方法。     

Salmonella on feces,hides and carcasses in beef slaughter facilities in Venezuela

This study determined Salmonella prevalence at different stages during the slaughtering in three beef slaughter plants (A, B and C) located in the western region of Venezuela (Zulia and Lara states). Each facility was visited three times at monthly intervals, from the months October through December of 2006. Samples were collected from hides (n = 80), fecal grabs (n = 80) and carcasses (n = 80) at the phases of pre-evisceration, after-evisceration and pre-cooler at three sampling sites on the animals (rump, flank and brisket). Salmonella prevalence was higher on hides (36.3%) than on feces (13.8%) (P < 0.05). Differences among slaughter plants for overall Salmonella prevalence were observed (P = 0.001; A: 3.5%, B: 11.1%, C: 4.4%). From the isolated strains, Salmonella enterica subspecies enterica ser. Saintpaul, Salmonella ser. Javiana and Salmonella ser. Weltevreden were identified. Cattle feces and hides might be considered as important sources of Salmonella for carcass contamination at different slaughter stages. The presence of potentially pathogenic Salmonella serotypes at the slaughtering stages is an evidence of the circulation of this pathogen in the food environment; its presence could increase consumers' risks of infection if proper food handling and preparation techniques are not followed. These data should serve as a baseline for future comparisons in Salmonella prevalence on beef carcasses to be used by the government and industry in order to establish preventive measures and to better address the risks of Salmonella contamination.     

Prevalence of Salmonella and Campylobacter in beef cattle from transport to slaughter

The objective of this study was to evaluate the effect of typical production practices during the transport of cattle on the resulting incidence of Salmonella and Campylobacter in the feces, on the hides, and on the carcasses of these cattle and in the environment (trucks, holding pens, and knock boxes). Various factors were evaluated, including the type of animal (feedlot cattle vs. adult pasture cattle), the breed of cattle, the body condition of the animal, the age of the animal, the time of feed and water withdrawal, the contamination level of the transport vehicle at the feedlot or farm, the transport time, the time cattle were held in the holding pen at the plant, and the contamination level of the holding pen. Four groups of each type of animal were sampled on different days. Samples were collected from cattle prior to transport and after transport (rectal and hide swabs) as well as from the carcasses of these cattle. Pre- and posttransit samples were also taken from the transport vehicle and from the holding pen and knock box at the slaughter facility. For feedlot cattle, fecal shedding stayed fairly constant for both organisms before and after transport (3 to 5% for Salmonella and 64 to 68% for Campylobacter). However, the shedding rate for adult cattle increased from 1 to 21% for Salmonella but stayed constant for Campylobacter (6 to 7%). Contamination of hides with Salmonella increased for both animal types from a level of 18 to 20% to a level 50 to 56%. For Campylobacter, the contamination level decreased from 25 to 13% for feedlot cattle but remained unchanged for adult animals (1 to 2%). Nineteen percent of feedlot cattle carcasses and 54% of adult cattle carcasses tested positive for Salmonella, while only2% of feedlot cattle carcasses and none of the adult cattle carcasses tested positive for Campylobacter. Thus, for feedlot cattle, the factors considered in this study did not affect the shedding of either organism but did affect the contamination of hides with both. For adult animals, the factors increased both shedding of and hide contamination with Salmonella only, not Campylobacter.     

Prevalence and numbers of Escherichia coli O157 on bovine hides at a beef slaughter plant

In this study, we investigated the prevalence and numbers of Escherichia coli O157 on bovine hides. Samples (n = 1,500) were collected over a 17-month period (30 samples per week) by sponge swabbing approximately 122-cm2 areas of the bovine rump of slaughtered cattle at an early stage of carcass processing (first legging). Sponge samples (n = 1,500) were stomached in buffered peptone water supplemented with novobiocin, directly plated on sorbitol MacConkey with Cefixime tellurite (SMAC-CT), enriched for 24 h, extracted by immunomagnetic separation, and plated onto SMAC-CT agar. Presumptive E. coli O157 colonies from SMAC-CT plates were confirmed by PCR for the presence of eaeA, hlyA, fliCh7, vt1, vt2, and portions of the rfb (O-antigen encoding) region of E. coli O157. Overall, E. coli O157 was recovered from 109 samples (7.3%) at concentrations ranging from less than 0.13 to 4.24 log CFU/100 cm2. PCR analysis revealed a wide diversity of genetic profiles among recovered isolates of verocytotoxigenic E. coli. Of the isolates recovered, 99 of 109 contained the attaching and effacing gene (eaeA) and the hemolysin gene (hlyA), and 78 of 109 had the flagellar H7 antigen-encoding gene (fliCh7). Only 6 of 109 isolates contained both verotoxin-producing genes (vt1 and vt2); 91 of 109 contained the vt2 gene only, whereas 1 of 109 contained the vt1 gene only. The remaining 11 of 109 contained neither vt1 nor vt2.     

宰前饮用复合磷酸盐水对延边黄牛肉贮藏品质的影响

以延边黄牛为研究对象,考察宰前分别饮用浓度为0.05%,0.10%,0.15%的复合磷酸盐水对宰后贮藏期牛肉的色泽、pH、持水力以及嫩度的影响。结果表明:宰前饮用复合磷酸盐水可提高贮藏期间延边黄牛肉的a*值以及保水性,进而改善牛肉的色泽和嫩度,在一定程度上提高延边黄牛肉品质,并以饮用0.10%的复合磷酸盐水最佳。     

Interventions to control Salmonella contamination during poultry,cattle and pig slaughter

The fundamental principle of controlling microbial contamination during slaughter is based on sanitary and hygienic processes. Both choosing abattoir technologies and conducting individual operations should be approached with the primary goal of minimizing microbial load on the final product. Nevertheless, even when best hygienic abattoir practices are applied, complete prevention of all microbial contamination of carcasses is unachievable under commercial conditions. Therefore, in some situations it may be considered necessary to further reduce the microbial loads on carcasses through application of additional control interventions, i.e. decontamination treatments. Treatments applied on poultry carcasses or parts include water, steam and chemical solutions (e.g., lactic or acetic acid, chlorine-based compounds, cetylpyridinium chloride, and trisodium phosphate) and result in overall microbial reductions of 0.6–3.8 log units; antimicrobial activity of some chemicals (e.g., chlorine compounds) is reduced in the presence of organic material. Decontamination treatments of hides (pre-skinning) and/or cattle carcasses reduce Salmonella by < 0.7–5.1 log units. Salmonella prevalence reductions achievable by decontamination of porcine carcasses seem to be at least two-fold. Overall Salmonella reductions on final carcasses and meat can be significantly improved when multiple decontamination treatments are applied sequentially during slaughter and dressing operations. It is important to note that decontamination interventions should be validated and considered as part of a hazard analysis critical control points (HACCP)-based food safety system which is subject to verification and auditing, and they should never be used as a substitute for good sanitation and proper hygiene practices.     

Studies to evaluate chemicals and conditions with low-pressure applications for reducing microbial counts on cattle hides

Studies were conducted to identify effective antimicrobials and application parameters that could be used as decontamination interventions to reduce microbial loads on cattle hides before removal from carcasses. In study I, hide swatches inoculated with Escherichia coli O157:H7 were sprayed with 10% acetic acid (at 23 and 55 degrees C), 10% lactic acid (at 23 and 55 degrees C), 3% sodium hydroxide (at 23 degrees C) or 4 and 5% sodium metasilicate (at 23 degrees C). All antimicrobials were evaluated independently after being applied alone, being applied after a water rinse, or being followed by a water rinse. Antimicrobial treatments followed by a water rinse lowered E. coli O157:H7 populations by 0.6 to 2.4 log CFU/cm2 and resulted in hides with a surface pH of 6.3 to 9.2. Treatments in which a water rinse was followed by antimicrobial application lowered E. coli O157:H7 populations by 1.5 to 5.1 log CFU/cm2 but resulted in hides with a surface pH of 3.9 to 10.5. In study II, whole hides were treated with one of four antimicrobials (acetic acid, lactic acid, sodium hydroxide, or sodium metasilicate) followed by a water rinse. Hides were evaluated for aerobic bacterial counts, total coliform counts, and E. coli counts. Generally, all antimicrobials resulted in greater reductions (P < 0.05) of E. coli counts when compared with the control; however, only acetic and lactic acids resulted in greater reductions (P < 0.05) of aerobic bacterial counts and total coliform counts compared with the controls. These antimicrobials could be used to reduce microbial contamination on hides, potentially reducing microbiological contamination transferred to carcasses or to the plant environment.     

Effects of a minimal hide wash cabinet on the levels and prevalence of Escherichia coli O157:H7 and Salmonella on the hides of beef cattle at slaughter

Harborage of Escherichia coli O157:H7 and Salmonella on animal hides at slaughter is the main source of beef carcass contamination during processing. Given this finding, interventions have been designed and implemented to target the hides of cattle following entry into beef processing plants. Previous interventions targeting hides have not been suitable for all beef processing plants because of cost and space restrictions. In this study, a hide wash cabinet was evaluated to determine whether it was more amenable to widespread use in the beef processing industry, especially for small and medium-size plants. Overall, 101 (35.1%) of 288 beef cattle hides sampled before entry into the hide wash cabinet harbored E. coli O157:H7 at or above the limit of detection (40 CFU/100 cm2). After passage through the hide wash cabinet, only 38 (13.2%) of 288 hides had E. coli O157:H7 levels > or =40 CFU/100 cm2. Before the hide wash cabinet, 50 (17%) of 288 hides harbored E. coli O157:H7 at levels above 100 CFU/100 cm2, with one sample as high as 20,000 CFU/100 cm2. In contrast, only 14 (5%) of 288 hides had E. coli O157:H7 levels above 100 CFU/100 cm2 after hide washing, with the highest being 2000 CFU/100 cm2. These same trends also were found for Salmonella before and after hide washing. These results indicate that the hide wash cabinet described in this study was effective and should provide small and medium-size processing plants with an affordable hide wash intervention strategy.     

生猪宰前静养规定研究

概述欧美等国屠宰法规有关静养的规定,探讨其存在的基础,对比其优缺点,并结合中国屠宰法规宰前静养规定实际生产中存在的问题,提出完善宰前静养规定的建议.     

蛋白酶在宰前嫩化和肉类加工中的应用

肉类是人类生活中不可缺少的食品。在肉的全部质量特征中,外观质量在很大程度上决定消费者是否选购,而消费者通常都把嫩度作为重要的特征。嫩度的变化取决于许多因素,它是可以改变的。一般来说,宰前因素对结缔组织的数量、分布和类型都有作用,从而影响着嫩度。     

Differences in the binding of human norovirus to and from romaine lettuce and raspberries by water and electrolyzed waters

Food contamination by human norovirus (hNoV) is a major cause of gastrointestinal disease. We evaluated the effectiveness of removing inoculated hNoV from the surfaces of raspberries and romaine lettuce by a simple wash in tap water and in different forms of electrolyzed water (EW), including acidic EW (AEW), neutral EW (NEW), and basic EW (BEW). A simple rinsing or soaking in water was able to remove >95% of hNoV from surface-inoculated raspberries. In contrast, only 75% of hNoV was removed from surface-inoculated romaine lettuce by rinsing in tap water. An AEW wash enhanced the binding of hNoV to raspberries and lettuce. Only 7.5% (±10%) and 4% (±3.1%) of hNoV were removed by AEW wash from surface-inoculated raspberries and lettuce, respectively. When raspberries and lettuce were prewashed with NEW or BEW prior to surface inoculation, an AEW wash likewise resulted in significantly less removal of hNoV compared with untreated samples. A prewash with AEW significantly decreased the removal of hNoV from raspberries and lettuce when they were washed with NEW, from 90.6 to 51% and from 76 to 51.3% , respectively. There are minimal or no improvements gained by use of any of the EWs instead of a regular tap water wash in removal of hNoV from produce. However, use of AEW shows a significant decrease in the removal of hNoV from contaminated produce compared with other water rinses. The ability to remove hNoV from different types of produce varies, possibly due to differences among types of ligand-like molecules that bind hNoV. The distribution of hNoV on raspberries and lettuce was studied using recombinant Norwalk-like particles (rNVLP). By immunofluorescence microscopy, we were able to observe binding of rNVLP only to vein areas of romaine lettuce, suggesting that the virus was binding to specific molecules in these areas. Random binding of rNVLP occurred only with raspberries prewashed with AEW or washed with AEW.