Microbiological baseline study of swine carcasses at Swedish slaughterhouses

This 13-month survey was conducted to estimate the prevalence and counts of foodborne pathogenic bacteria and indicator bacteria on swine carcasses in Sweden. A total of 541 swine carcasses were sampled by swabbing prechill at the 10 largest slaughterhouses in Sweden. Pathogenic Yersinia enterocolitica was detected by PCR in 16% of the samples. The probability of finding Y. enterocolitica increased with increasing counts of Escherichia coli. No samples were positive for Salmonella. The prevalences of Campylobacter, Listeria monocytogenes, and verocytotoxin-producing E. coli were low (1, 2, and 1%, respectively). None of the verocytotoxin-positive enrichments, as determined by a reverse passive latex agglutination assay, tested positive for the virulence genes eaeA or hlyA by PCR. Coagulase-positive staphylococci, E. coli, and Enterobacteriaceae were recovered from 30, 57, and 87% of the samples, respectively, usually at low levels (95th percentiles, 0.79, 1.09, and 1.30 log CFU/cm2, respectively). The mean log level of Enterobacteriaceae was 0.35 log CFU/cm2 higher than that of E. coli on carcasses positive for both bacteria. The mean log level of aerobic microorganisms was 3.48 log CFU/cm2, and the 95th percentile was 4.51 log CFU/cm2. These data may be useful for risk assessment purposes and can serve as a basis for risk management actions, such as the use of E. coli as an alternative indicator organism for process hygiene control.     

Microbiological contamination of pig and cattle carcasses in different small-scale Swiss abattoirs

A total of 750 pig carcasses and 535 cattle carcasses from 17 small-scale abattoirs were sampled by excision at four sites (pig: neck, belly, back, ham; cattle: neck, brisket, flank, rump). Samples were examined for total viable counts (TVC) and Enterobacteriaceae. Mean TVCs ranged from 2.4 to 4.2 log(10)CFUcm(-2) on pig carcasses and from 2.7 to 3.8 log(10)CFUcm(-2) on cattle carcasses. With regard to EU Regulation (EC) No 2073/2005, TVCs were mainly considered satisfactory (pig: 81.3%; cattle: 71.4%). Amongst sites, the back (pigs) and neck (cattle) tended to yield higher TVCs. Enterobacteriaceae were detected in low counts on 23.9% of pig carcasses and 21.7% of cattle carcasses. Amongst abattoirs, Enterobacteriaceae prevalence on pig and cattle carcasses ranged from 2.0% to 56.0% and from 0.0% to 55.0%, respectively. Consequently, criteria of the EU Regulation proved to be a suitable tool for the appraisal of microbiological results (TVCs) from pig and cattle carcasses from small-scale abattoirs. Because the occurrence of Enterobacteriaceae on carcasses was too infrequent to ensure log normality, frequencies should be compared for these organisms.     

Campylobacter contamination in broiler carcasses and correlation with slaughterhouses operational hygiene inspection

This study investigates factors associated with Campylobacter contamination of broiler carcasses, using survey data collected from nine Belgian slaughterhouses in 2008 in accordance with a European Union baseline study. Campylobacter were detected in 51.9% (202/389) (95% confidence interval, 46.8%-56.9%) of broiler carcasses. Campylobacter concentration was <10 CFU/g in 49.6% of carcasses, while 20.6% were contaminated with ≥1000 CFU/g. The mean Campylobacter concentration, as calculated by maximum likelihood estimation for left-censored data, was 1.8 log₁₀ CFU/g, with a standard deviation of 1.9 log₁₀ CFU/g. There was statistically significant variation among slaughterhouses in prevalence and concentrations of Campylobacter in their sampled carcasses. Campylobacter prevalence (but not concentrations) was positively associated with increase in broilers age. Both Campylobacter prevalence and concentration were significantly higher in carcasses sampled during June and September (but not in July and August) than carcasses sampled in January. We also investigated the correlation (Spearman’s rank correlation test) between the scores of official control inspections and Campylobacter prevalence for eight out of the nine slaughterhouses. The control inspections were routinely performed by the Belgian Federal Agency for the Safety of the Food Chain, and the concluded inspection scores were used as a general numerical indicator for the status of operational hygiene and quality of management in the slaughterhouses. Ranking of slaughterhouses based on their inspection scores was statistically correlated (Spearman’s correlation coefficient = 0.857) with their ranking based on prevalence of Campylobacter. In the present study we demonstrate how the outcomes from a routine baseline survey could be coupled with other readily available data from national control authorities in order to enable a better insight over Campylobacter contamination status in broiler slaughterhouses. Findings from this work call for subsequent in-depth investigations on technical and hygiene management factors that could impact Campylobacter contamination across broiler slaughterhouses.     

Microbiological contamination of pig carcasses at different stages of slaughter in two European Union-approved abattoirs

At sequential steps of slaughter (scalding, dehairing, singeing, polishing, trimming, washing, and chilling), 200 pig carcasses from two abattoirs were examined for total viable bacteria count (TVC) and the presence of Enterobacteriaceae and coagulase-positive Staphylococcus (CPS) by the wet-dry double-swab technique at the neck, belly, back, and ham. Before scalding, mean TVCs ranged from 5.0 to 6.0 log CFU cm(-2), and Enterobacteriaceae and CPS were detected on all carcasses. At abattoir A, mean TVCs and the percentage of Enterobacteriaceae-positive carcasses were reduced (P < 0.05) after scalding (1.9 log CFU cm(-2) and 12%, respectively), singeing (1.9 log CFU cm(-2) and 66%, respectively), and blast chilling (2.3 log CFU cm(-2) and 17%, respectively) and increased (P < 0.05) after dehairing (3.4 log CFU cm(-2) and 100%, respectively) and polishing (2.9 log CFU cm(-2)). The proportion of CPS-positive samples decreased to < or = 10% after scalding and remained at this level. At abattoir B, mean TVCs and the percentages of Enterobacteriaceae- and CPS-positive carcasses were reduced (P < 0.05) after scalding (2.4 log CFU cm(-2) and 29 and 20%, respectively), polishing (3.7 log CFU cm(-2)), and chilling (2.6 log CFU cm(-2) and 55 and 77%, respectively) and increased (P < 0.05) after the combined dehairing-singeing (4.7 log CFU cm(-2) and 97 and 100%, respectively). Among sites, the neck tended to yield higher levels of contamination from trimming to chilling at both abattoirs (P < 0.05). Consequently, scalding, singeing, and chilling may be integrated in a hazard analysis critical control point (HACCP) system for pig slaughter. As indicated by the higher levels of contamination on carcasses after dehairing-singeing and the following stages at abattoir B, each abattoir should develop its own baseline data and should customize HACCP systems to match process- and site-specific circumstances.     

青岛市屠宰场整鸡中沙门菌污染水平定量检测及耐药性分析

目的调查青岛市规模化肉鸡屠宰场屠宰后整鸡样品中沙门菌的污染及抗生素耐药谱分布状况。方法2014年10~12月在青岛市选择2家规模化肉鸡屠宰场,采用胴体漂洗法定量检测3次共采集的141份屠宰后整鸡样品中沙门菌,根据Kauffmann-White表对沙门菌菌株进行血清学鉴定,应用微量肉汤稀释法检测菌株对11种抗生素的耐药性。结果整鸡样品沙门菌总体污染率为74.5%(105/141),污染水平3.6~1 100 MPN/100 g,中位数为43 MPN/100 g;共分离355株沙门菌,血清型分布为肠炎沙门菌220株,印第安纳沙门菌88株和阿贡纳沙门菌19株,以及其他型28株。355株沙门菌分离株的总体耐药率为90.4%(321/355),萘啶酸(NAL)耐药率最高(88.7%,315/355)。220株肠炎沙门菌中219株(99.5%)耐药,6株(2.7%)为多重耐药株,优势耐药谱为奈啶酸(156株)。88株印第安纳沙门菌均耐药,85株为多重耐药株,优势耐药谱为庆大霉素-氯霉素-环丙沙星-萘啶酸-氨苄西林-青霉烷砜/氨苄西林-头孢他啶-头孢噻肟-复方新诺明。19株阿贡纳沙门菌除1株对奈啶酸耐药外,其余18株对所测试11种抗生素均敏感。结论青岛市肉鸡屠宰场沙门菌污染率较高,血清型以肠炎沙门菌、印第安纳沙门菌和阿贡纳沙门菌为主。沙门菌总体耐药率较高,并呈现多重耐药性趋势。     

Characteristics of Staphylococcus hyicus strains isolated from pig carcasses in two different slaughterhouses

In a previous study, we showed that coagulase positive staphylococci, which are often used as indicators for Staphylococcus aureus, are frequently found on pig carcasses. Further characterization of the strains identified only a minor part as S. aureus. Selected non-S. aureus strains were all identified as Staphylococcus hyicus, However, two studies described in this species strains that produce staphylococcal enterotoxins. The aim of the present study was to further characterize such coagulase positive S. hyicus strains isolated from pig carcasses and to assess the results for their food safety relevance. A total of 189 strains from two abattoirs were characterized. Phenotypically, 98.9% showed non-pigmented colonies, 99.5% no haemolysis and 67.7% were egg yolk-positive. DNase activity was found in all but one isolate. Only five of the 189 strains were resistant to the antimicrobials tested. One strain harboured the mecA gene. Exfoliative toxin genes were detected in 31 (16.4%), S. aureus enterotoxin genes in none of the strains.The PFGE genotyping results show only a limited number of clusters. Cluster I included more than 50% of the strains. The fact that similar or closely related PFGE patterns of S. hyicus can be found on carcasses after bleeding in both abattoirs indicates the occurrence of widespread strains in the Swiss pig population. Moreover, the genotyping results revealed a remarkable homogeneity in S. hyicus strains isolated from different process stages in abattoir B, which could indicate a recontamination problem with persisting strains.     

Microbiological conditions of detained beef carcasses before and after removal of visible contamination

The microbiological conditions of carcasses detained for the removal of visible contamination at four beef packing plants were examined. The numbers of aerobes and Escherichia coli recovered from most visibly contaminated sites did not exceed numbers generally regarded as acceptable for beef carcasses. The numbers of bacteria at visibly contaminated sites were reduced when those sites were trimmed, but additional and/or routine decontaminating treatments after trimming gave greater reductions in numbers at three of the plants. At each plant, at the end of the dressing process, the microbiological condition of the carcasses that had been detained was similar or superior to the condition previously determined for carcasses routinely produced from the process.     

Measurement of Campylobacter numbers on carcasses in British poultry slaughterhouses

An assessment of the proposed new International Organization for Standardization quantitative method for Campylobacter was undertaken on poultry carcass samples collected after the chilling phase of processing. Using a critical differences method, we determined the uncertainty associated with log-transformed Campylobacter numbers by dual analyses of 346 samples collected from 22 processing plants located throughout the United Kingdom. Overall, using log-transformed Campylobacter numbers that ranged between -1 and 5 log, we calculated the expanded measurement of uncertainty (EMU) to be 3.889 for the new method. The EMU changed when ranges of bacterial numbers were grouped for analyses. For low numbers of Campylobacter (< 1 log), the EMU was calculated to be 5.622. There was less measurement error with higher bacterial numbers because the EMU was found to be 0.612 for samples containing Campylobacter numbers of 3 log or above. The draft method was used to measure numbers of Campylobacters on poultry carcasses collected from 18 United Kingdom processing plants in summer and winter. Numbers were significantly lower in winter. We conclude that, although the new method is adequate at quantifying high numbers of Campylobacter on poultry carcasses, further development is required to improve the measurement of small numbers of this causative agent of foodborne illness.     

Listeria monocytogenes contamination pattern in pig slaughterhouses

Ten low-capacity slaughterhouses were examined for Listeria by collecting a total of 373 samples, of which 50, 250, and 73 were taken from carcasses, pluck sets, and the slaughterhouse environment, respectively. Six slaughterhouses and 9% of all samples were positive for Listeria monocytogenes. Of the samples taken from pluck sets, 9% were positive for L. monocytogenes, the highest prevalence occurring in tongue and tonsil samples, at 14% and 12%, respectively. Six of 50 (12%) carcasses were contaminated with L. monocytogenes. In the slaughterhouse environment, L. monocytogenes was detected in two, one, one, and one sample originating from the saws, drain, door, and table, respectively. Carcasses were contaminated with L. monocytogenes in those two slaughterhouses, where the mechanical saws, used for both brisket and back splitting, were also positive for L. monocytogenes. A total of 58 L. monocytogenes isolates were characterized by pulsed-field gel electrophoresis typing. The isolates were divided into 18 pulsotypes, 15 of which were detected in pluck sets. In two slaughterhouses, where the carcasses were contaminated with L. monocytogenes, the same pulsotypes were also recovered from splitting saws. In addition, identical pulsotypes were recovered from pluck sets. Our findings indicate that L. monocytogenes of tongue and tonsil origin may contaminate the slaughtering equipment that may in turn spread the pathogen to carcasses. Thus, it is of the utmost importance to follow good manufacturing practices and to have efficient cleaning and disinfection procedures to prevent equipment being contaminated with L. monocytogenes.     

Airborne bacteria and carcass contamination in slaughterhouses.

Microbiological contamination of air and carcasses was studied in four slaughterhouses by using impactor samples taken at the back-splitting and weighing areas and by sampling carcasses with the swabbing method. Air flow was determined by an air-flow detector, and the movement of workers was observed. The air contamination level in the back-splitting areas (2.25 log CFU/100 liters of air) was generally higher than that in the weighing areas (2.03 log CFU/100 liters of air). Associations between the microbiological contamination of air and carcasses with the movements of workers were found. Layout of the slaughtering line was shown to be important in decreasing airborne contamination. Separation of the clean and unclean parts of the line as well as separation of the weighing area from the other clean parts of the line decreased the contamination level. It appears that airborne bacteria have an important role in carcass contamination.     

Microbiological baseline study of broiler chickens at Swedish slaughterhouses

This 1-year study was conducted to estimate the prevalence and concentrations of pathogenic and indicator bacteria on Swedish broiler chickens. A total of 636 chilled carcasses were collected from 10 slaughterhouses and sent to the National Food Administration for analyses of carcass rinses. No carcasses were positive for Salmonella. Campylobacter, predominantly Campylobacter jejuni, were detected on 15% (by enrichment) or 14% (by direct plating) of the carcasses. With one exception, all samples from late December through April were Campylobacter negative. The 10th and 90th percentiles of Campylobacter numbers per carcasses were 3.0 and 5.0 log CFU, respectively, and the maximum was 7.1 log CFU. Coagulase-positive staphylococci were detected on 68% of the carcasses, with a maximum of 3.5 log CFU/cm2. The 10th and 90th percentiles were 3.4 and 4.4 log CFU/cm2 for total aerobic microorganisms, 1.8 and 3.3 log CFU/cm2 for Enterobacteriaceae, and 2.0 and 3.6 log CFU/cm2 for Escherichia coli. No correlation was found between numbers of any indicator bacteria and numbers of pathogenic bacteria. Subsets of the samples were analyzed for Listeria monocytogenes, Clostridium perfringens, pathogenic Yersinia enterocolitica, and Enterococcus, resulting in prevalence estimates of 29, 18, 9 (as determined by a PCR assay), and 97%, respectively. L. monocytogenes was most common at slaughterhouses with a low prevalence of coagulase-positive staphylococci, and vice versa. These results will improve the ability of researchers to assess the importance of chicken as a source of foodborne pathogens and can serve as a basis for risk management actions.     

Microbiological meat quality in high- and low-capacity slaughterhouses in Sweden

The purpose of this study was to investigate the bacterial count on beef and pork carcasses, a comparison being made between different-sized slaughterhouses in Sweden. Samples were taken from the flank and sternum of 200 beef and 200 pork carcasses, with half of the samples being collected from low-capacity slaughterhouses. Sampling was carried out at the end of the slaughter-line from 25 beef carcasses and/or 25 pork carcasses in each abattoir. Analyses were performed of the aerobic microorganisms, coliform bacteria, coagulase-positive staphylococci, and presumptive Escherichia coli. No significant differences were found in the amount of aerobic microorganisms between pork carcasses from low- and high-capacity slaughterhouses. In beef carcasses, however, there was a significantly greater amount of aerobic microorganisms in beef carcasses slaughtered at low-capacity slaughterhouses. Within the group of high-capacity abattoirs there was a very small variation in the amount of aerobic bacteria between the different slaughterhouses that could be explained by their having almost the same evisceration technique. The evisceration technique differs more among the low-capacity slaughterhouses, which is probably the main reason for the wide variation in the amount of aerobic bacteria. Coliform bacteria, coagulase-positive staphylococci, and presumptive E. coli were more common on pork carcasses than on beef carcasses. There were also significantly higher amounts of these bacteria in pork carcasses from the high-capacity slaughterhouses.     

Microbiological quality of retail poultry carcasses in Spain.

A total of 40 eviscerated and refrigerated chicken carcasses were collected from five retail outlets (three supermarkets and two poulterers' shops) in León (Spain). The level of microorganisms on chicken carcasses was assessed using the excised breast-skin technique. Mean counts (log10 CFU/g) of psychrotrophs, pseudomonads, fluorescent pseudomonads, enterococci, Micrococcaceae, Staphylococcus aureus, and yeasts and molds were 4.84, 4.11, 3.32, 2.72, 3.80, 3.67, and 2.99, respectively. A significant correlation coefficient was found between pseudomonads and fluorescent pseudomonad counts (r = 0.827; P < 0.001) and between Micrococcaceae and S. aureus counts (r = 0.915; P < 0.001). Levels of psychrotrophs, pseudomonads, fluorescent pseudomonads, and yeasts and molds were significantly (P < 0.05) higher in supermarkets than in poulterers' shops, possibly due to the longer period of time the carcasses spent in the supermarkets (between 1 and 2 days, as opposed to only 4 to 16 h in the case of poulterers' shops). Carcasses from poulterers' shops showed higher (P < 0.05) counts of enterococci. Micrococcaceae, and S. aureus, which suggests higher storage temperatures in these outlets. Only S. aureus counts (especially those from poulterers' shops) exceeded the established values in the microbiological criteria for poultry meat consulted.     

Microbiological sampling of carcasses by excision or swabbing

Groups of 25 carcasses were obtained by random selection of carcasses at the end of each of eight commercial processes for the dressing or cooling of carcasses. Samples were collected from six groups of pig or beef carcasses by excision or swabbing with sponge, gauze, or cotton wool, with one sample obtained by each of the four methods from a separate, randomly selected site on each carcass. Total aerobic counts, coliforms, and Escherichia coli from each sample were enumerated. Values for the mean log10, log10 mean, and log10 total numbers recovered were calculated for each set of total aerobic counts. Those statistics indicated that the numbers of bacteria recovered by excision or swabbing with sponge or gauze were similar, while the numbers recovered by swabbing with cotton wool were at the lower end of or below the range of the numbers recovered by the other methods. The numbers of coliforms or E. coli recovered from carcasses by sampling areas up to 100 cm2 were too few for the estimation of log mean numbers. Sampling of two groups of carcasses by swabbing with gauze indicated that each 10-fold increase in the area sampled, from 10 to 1,000 cm2, approximately doubled the number of samples from which coliforms or E. coli were recovered. Sampling of six groups of carcasses from one process indicated that the sizes of swabs and volumes of diluent used for processing swabs did not have to be increased proportionally to the area of carcass surface sampled to recover numbers of E. coli proportional to the sampled area. It therefore appears that carcass sampling techniques can be varied widely without compromising the recovery of bacteria, and that the relative efficiencies with which bacteria are recovered by different techniques can be assessed by sampling each carcass in a group of 25 by each of the methods to be compared.     

Detection and characterization of Salmonella in lairage, on pig carcasses and intestines in five slaughterhouses

In this study, conducted at five slaughterhouses, individual pigs were sampled and followed up from stunning to cooling down of the carcasses. In this way, Salmonella prevalence and possible risk points were described. At the lairage area, pens were sampled using overshoes. At stunning and bleeding, pigs were individually identified and subsequently swabs were taken of the oral cavity and the carcass after polishing, splitting and forced chilling. Additionally, duodenum, ileum, rectum and mesenteric lymph nodes were extracted and samples were taken of the scalding water. All samples were submitted to Salmonella isolation and Salmonella isolates were serotyped and genotyped by pulsed-field gel electrophoresis (PFGE). Of all samples taken (n = 1953), 14.1% were Salmonella positive. The prevalence of S. in the lairage area varied widely (from 0 to 100%) between the slaughterhouses. Of the sampled pigs (n = 226), 48.2% were positive in at least one sample. Statistical analysis revealed that the contamination of the lairage area was related to a higher amount of positive carcasses after polishing. Furthermore, the contamination of the carcasses after splitting and forced chilling was related to the contamination level of the carcass after polishing. A relation between the outer (carcass) contamination and the inner (gut content and lymph nodes) contamination of a pig could not be established. The predominant serotypes were S. Typhimurium (58.7%) and S. Derby (17.4%). Genotyping revealed 46 different PFGE profiles among the 276 Salmonella isolates. The same genotype at the lairage area as in the oral cavity of the pigs was found in 95%. The results indicate that the lairage area is a primary source of Salmonella in slaughter pigs and that carcass contamination originates from the environment rather than from the pig (inner contamination) itself. It further shows that slaughterhouses vary in their capability of dealing with Salmonella positive pigs. A slaughterhouse specific approach is needed, however, general guidelines should be provided to decrease the contamination level of the lairage area and the slaughter environment.     

Microbiological contamination of fresh-cut produce in Korea

Food Science and Biotechnology - This study evaluated the microbiological contamination of fresh-cut produce in Korea. A total of 108 fresh-cut vegetables and fruits were surveyed for the aerobic...     

肉鸡屠宰加工过程中胴体微生物污染分析及不同冲淋条件对胴体减菌的影响

测定肉鸡在屠宰加工过程中脱毛后、掏内脏后、胴体清洗后、预冷后、分割后、速冻后胴体表面的菌落总数、大肠菌群、肠球菌数量以及检测产品的金黄色葡萄球菌、沙门氏菌;通过对不同浓度乳酸、不同温度热水、不同冲淋时间进行均匀设计分组,冲淋处理胴体清洗前的肉鸡胴体,测定其菌落总数。肉鸡在整个屠宰生产链上胴体污染的菌落总数、大肠菌群和肠球菌数分别为4.56⁵.74、2.665.74、2.66⁴.81、2.014.81、2.01³.57(log10CFU/cm2)。肉鸡产品的菌落总数4.57(log10CFU/cm2)符合GB16869-2005鲜、冻禽产品标准,大肠菌群3.50(log10 CFU/cm2)、金黄色葡萄球菌、沙门氏菌的检出率分别为37.25%、12.75%,不符合标准,肠球菌没有限量标准,但产品的肠球菌数(2.53(log10CFU/cm2))较高;对肉鸡胴体表面减菌的适宜条件为乳酸浓度1.5%、热水温度50℃、冲淋时间15 s,可减少菌落总数1.998(log10CFU/cm2)。肉鸡屠宰过程中胴体微生物污染较严重,存在致病菌污染,乳酸结合热水冲淋可显著减少肉鸡胴体表面的菌落总数。     

Microbiological conditions of sheep carcasses from conventional or inverted dressing processes

At a small abattoir, 25 sheep carcasses were dressed conventionally, with the carcass suspended by the rear legs, and 25 carcasses were dressed while inverted, with the carcasses suspended by the forelegs. Two swab samples were obtained from randomly selected sites on each carcass, and total aerobic, coliform, and Escherichia coli counts were enumerated for each sample. Each type of count was arranged in two sets of 25 counts for each type of dressing process, and a log mean number and/or log total number recovered was calculated for each set of counts. The log mean number of total aerobic counts for one set of counts from carcasses dressed while inverted was less than the corresponding log mean numbers for both sets from the conventionally dressed carcasses and the other set from the carcasses dressed while inverted, and differed from them by about 0.7 log units. The coliforms recovered from carcasses were largely E. coli. The log total numbers of coliform or E. coli counts recovered from carcasses dressed while inverted were about 1.5 log units less than the corresponding log total numbers recovered from conventionally dressed carcasses. Those data indicate that the substitution of inverted for conventional dressing might serve to reduce the numbers of E. coli on sheep carcasses by reducing the microbiological contamination of the hindquarters but that the general microbiological condition of the carcasses would be little improved unless some means of preventing or removing contamination of the forequarters was also used.     

Microbiological contamination of cattle and pig carcasses at five abattoirs determined by swab sampling in accordance with EU Decision 2001/471/EC

A total of 800 cattle carcasses (abattoir A: n=200; B: n=150; C: n=150; D: n=150, E: n=150) and 650 pig carcasses (abattoir A: n=200; B: n=150; C: n=150; D: n=150) were examined at five Swiss abattoirs with an annual slaughtering capacity >10 million kg. Weekly, 10 cattle and 10 pig carcasses were sampled at four sites by the wet-dry double swab technique. From each carcass the samples were pooled and examined for total viable counts (TVC) and Enterobacteriaceae. At the abattoirs, mean log TVCs from cattle carcasses ranged from 2.1 to 3.1 cm(-2) and those from pig carcasses from 2.2 to 3.7 cm(-2). Daily TVC mean log values showed significant differences between abattoirs (P<0.05), whereas no significant differences were detected between animal species. On average, Enterobacteriaceae were detected (i) in low counts, (ii) on 31.0% of cattle and on 20.2% of pig carcasses, and (iii) more frequently and in higher counts on cattle than on pig carcasses (P<0.05). Data from this study indicate that the wet-dry double swab technique is suitable to determine microbiological contamination of cattle and pig carcasses in accordance with EU Decision 2001/471/EC. For samples obtained by the non-destructive technique from cattle and pig carcasses, the following microbiological performance criteria are proposed: Daily mean log values are acceptable, marginal, and unacceptable for TVC when they are <3.00, 3.00-4.00, >4.00 cm(-2), and for Enterobacteriaceae when they are <1.00, 1.00-2.00, and >2.00 cm(-2). However, such values have to be seen merely as baselines. It is important to implement a monitoring system based on abattoir-specific data and criteria as permitted by quality control chart methods.     

Microbiological effects of acid decontamination of pork carcasses at various locations in processing

The microbiological effect of hot (55° C), 1% (v/v) lactic acid sprayed on the surface of pork carcasses (n = 36) immediately after dehairing, after evisceration (immediately before chilling) or at both locations in slaughter/ processing was determined. Mean aerobic plate counts (APCs) of all acid-treated carcass surfaces were numerically lower than those of control carcasses: however, in most cases these reductions were not statistically significant (P>0·05). All samples tested for the presence of Salmonella and Listeria were negative. No significant differences in sensory characteristics or microbiological counts were evident for acid-treated and control carcass loins that were vacuum packaged and stored 0–14 days post-fabrication. Mean pH value and scores of sensory attributes such as lean color, surface discoloration, fat color, overall appearance and off-odor of chops from acid-treated carcasses were not significantly and/or consistently different from chops of comparable control carcasses. The role of bacterial attachment to pork skin and its effect on the decontaminating efficiency of lactic acid are discussed.