An investigation on the effect of transport and lairage on the faecal shedding prevalence of Escherichia coli O157 in cattle

The aim of the study was to investigate the effect of transport and lairage on the prevalence of Escherichia coli O157 faecal shedding and the subsequent contamination of beef carcasses. Individual rectal faecal samples were taken from two cohorts of cattle (109 and 59) at the farm before transport and at the abattoir post-transport and lairage. The entire outer and inner surfaces of the carcass of each animal were swabbed immediately following slaughter and dressing. The prevalence of E. coli O157 shedding in cattle sampled at farm, post-transport and lairage was 18% (20), 13% (14) and 12% (13) for cohort A and 1.7% (1), 1.7% (1) and 0 for cohort B, respectively. No E. coli O157 was recovered from the 168 dressed carcasses. In total, 98% (46 of 47) of the E. coli O157 isolates from cohort A were potentially pathogenic to man. Transport and lairage do not cause an increase in the prevalence of E. coli O157 faecal shedding in cattle. This study demonstrates that even positive cohorts of cattle may be slaughtered and processed to produce clean carcasses by following good hygienic practices.     

Microbiological baseline study of beef and pork carcasses from provincially inspected abattoirs in Alberta, Canada

In 2006 and 2007 beef and pork carcass swabs from provincially inspected abattoirs in Alberta, Canada were tested to determine the levels of total aerobic bacteria, coliform bacteria, and generic Escherichia coli, and the prevalence of Salmonella spp., Campylobacter spp., and Shiga toxin-producing E. coli (STEC). Swabs from beef and pork carcasses from 48 and 34 facilities, respectively, were analyzed. All samples tested were positive for aerobic bacteria with 99.8% of beef and 96.0% of pork samples, having total counts of ≤ 100 000 CFU/cm(2). Coliform bacteria were isolated from 22.4% and 42.0% of beef and pork carcass samples, respectively. Generic E. coli were recovered from 14.6% of beef and 33.7% of pork carcass samples. For beef carcasses, positive tests were obtained for 0.1% of 1036 samples tested for Salmonella spp., 1.5% of 1022 samples tested for Campylobacter spp. and 5.4% of 1018 samples tested for STEC. For pork carcasses, positive tests were obtained for 1.6 % of 1076 samples tested for Salmonella spp., 8.8% of 1070 samples tested for Campylobacter spp. and 4.8% of 1067 samples tested for STEC.     

Phenotypic and genotypic heterogeneity of Campylobacter coli within individual pigs at farm and slaughter in the US

The aim of this study was to determine the phenotypic and genotypic diversity of multiple Campylobacter isolates (n = 3 per sample) present within individual (heterogeneity) pig faecal and carcass samples at farm and slaughter, respectively. We isolated 1459 Campylobacter coli (1110 on farm and 349 from slaughter) from 908 pigs and 757 carcasses and characterized them for their antimicrobial susceptibility profile to a panel of six antimicrobials using the agar dilution method. Overall, we detected a significantly higher Campylobacter prevalence at the farm (54.7%) than at slaughter (19%) level (P < 0.05). C. coli isolates were resistant most commonly to tetracycline (66.2%) and erythromycin (53.6%) while fluoroquinolone resistance was detected in isolates (n = 17) only from the farm level. Phenotypic diversity of C. coli isolates at the 4-fold minimum inhibitory concentration levels within the same sample was detected in 38.6% (n = 192) pigs and 40.2% (n = 58) carcass swabs with no significant difference between the two sources (P = 0.72). Phenotypic heterogeneity based on the antimicrobial resistance patterns was observed in 32.5% (n = 162) of the farm samples and in 30.5% (n = 44) carcass swabs at slaughter (P = 0.64). A subset of 40 isolates representing ten pigs and eight carcass samples (originating from separate pigs) were further genotyped by multi locus sequence typing. The observation of phenotypic diversity was replicated at the genotypic level, as it was highlighted by the 22 sequence types which represented the 40 isolates. In conclusion, we detected multiple C. coli subtypes from individual pig or carcass samples indicating unprecedented level of heterogeneity. Our study clearly signifies the importance of testing multiple colonies to make appropriate and valid conclusions in epidemiological-based studies.     

Campylobacter spp. in Irish feedlot cattle: a longitudinal study involving pre-harvest and harvest phases of the food chain

The aim of this study was to investigate faecal shedding and transmission of Campylobacter spp. in cohorts of cattle within a feedlot, to assess subsequent contamination of carcasses with this pathogen and to identify risk factors associated with faecal shedding of Campylobacter spp. A cohort of 133 heifers housed in four adjacent pens was examined over a five and a half month period, from entering the feedlot to slaughter. A parallel investigation of individual rectal faecal samples and pen environmental samples were taken at monthly intervals from November to February. The entire outer and inner surfaces of a carcass side of each animal were swabbed immediately following slaughter. Campylobacter spp. were isolated from 322 (54%) of the 600 rectal faecal samples. Campylobacter jejuni and C. coli accounted for 69 and 29.7% of the isolate recovered, respectively. A total of 159 environmental samples were examined, of these Campylobacter spp. was isolated from 46 samples (29%). Campylobacter jejuni and C. coli accounted for 35 and 59% of these isolates, respectively. Campylobacter spp. was not isolated from any of the dressed carcasses. Logistic regression indicated prevalence of Campylobacter spp. faecal shedding within pens was positively correlated to the pen, the month of sampling and the Campylobacter spp. contamination status of the pen dividing bars and the water trough surface. Campylobacter spp. should be considered as a pathogen shed in the faeces of a substantial proportion of feedlot cattle. However, with good hygienic practice during harvest, a very low level of this pathogen can be achieved on dressed carcasses.     

Prevalence of Campylobacter spp. and Yersinia spp. in the pig production

The aim of this study was to determine the prevalence of Campylobacter spp. and Yersinia spp. in a total of 1,040 faecal samples taken from animals at different ages from four farrowing and twelve fattening herds. In the farrowing unit, faeces were collected from 68 sows (faecal samples) and 256 suckling piglets (rectal swab samples). Further samples were collected from 362 growing and 354 finishing pigs (rectal swab samples). Additionally, 56 feed and environmental samples were collected. During the slaughtering process, 122 pigs and their carcasses respectively, were sampled three times. Finally, 86 meat and minced meat samples were taken from 34 retail stores. Campylobacter spp. were isolated in sows (33.8 %), piglets (80.9 %), growing (89.2 %) and finishing (64.7 %) pigs. Yersinia spp. were detected in growing (15.2 %) and finishing (13.3 %) pigs only. After twelve hours of chilling neither Campylobacter spp. nor Yersinia spp. were detected. In raw meat samples, Campylobacter spp. were isolated from one liver sample and Yersinia enterocolitica from two meat samples. Common slaughter techniques and hygiene procedures may be effective tools to reduce the risk of contamination and recontamination of meat products since Campylobacter spp. and Yersinia spp. were found only sporadically in raw meat samples.     

Distribution of Campylobacter jejuni isolates from turkey farms and different stages at slaughter using pulsed-field gel electrophoresis and flaA-short variable region sequencing

The aim of this study was to assess the diversity of thermotolerant Campylobacter spp. isolated from turkey flocks at six rearing farms 1-2 weeks prior to slaughter (360 faecal swab samples) and from 11 different stages at the slaughterhouse (636 caecal, environmental, neck skin and meat samples). A total of 121 Campylobacter isolates were identified to species level using a multiplex PCR assay and were typed by pulsed-field gel electrophoresis (PFGE) and flaA-short variable region (SVR) sequencing. All Campylobacter isolates were identified as Campylobacter jejuni. PFGE analysis with KpnI restriction enzyme resulted in 11 PFGE types (I-XI) and flaA SVR typing yielded in nine flaA-SVR alleles. The Campylobacter-positive turkey flocks A, C and E were colonized by a limited number of Campylobacter clones at the farm and slaughter. The present study confirms the traceability of flock-specific strains (PFGE types I, V and IX; flaA types 21, 36 and 161) from the farm along the entire processing line to meat cuts. It seems that stress factors such as high temperature of the defeathering water (54-56 °C), drying of the carcass skin during air chilling (24 h at 2 °C), and oxygen in the air could not eliminate Campylobacter completely. Campylobacter-negative flocks became contaminated during processing by the same subtypes of Campylobacter introduced into the slaughter house by preceeding positive flocks even if they were slaughtered on subsequent days. Proper and efficient cleaning and disinfection of slaughter and processing premises are needed to avoid cross-contamination, especially in countries with a low prevalence of Campylobacter spp. The majority of flaA SVR alleles displayed a distinct association with a specific PFGE type. However, a linear relationship for all strains among both typing methods could not be established. To specify genetic relatedness of strains, a combination of different genotyping methods, is needed.     

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     

Simultaneous occurrence of selected food-borne bacterial pathogens on bovine hides, carcasses and beef meat

The aim of this study was to determine the simultaneous occurence of Salmonella spp., L. monocytogenes, verotoxigenic E. coli (VTEC), and Campylobacter spp. in slaughtered cattle and in beef meat subjected for human consumption. A total of 406 bovine hides and 406 corresponding carcasses were used to collect the samples with a swab method after exsanguination and evisceration of animals, respectively. Furthermore, 362 beef meat samples were purchased in local retail shops over the same period of time as for the bovine samples. Food-borne bacterial pathogens were identified with standard ISO methods with some modification by the use of PCR for VTEC. The isolated bacteria were then molecularly speciated (Campylobacter), serotyped (L. monocytogenes) and characterized for the presence of several virulence marker genes (VTEC and Campylobacter). It was found that 49 hide (12.1%) and 3 (0.7%) carcass samples were contaminated with more than one bacterial pathogen tested. Most of the hides were positive for Campylobacter spp. and VTEC (27 samples) and Campylobacter spp. together with L. monocytogenes (12 samples). Eight bovine hides contained L. monocytogenes and VTEC while L. monocytogenes and Salmonella spp. were detected in one sample. Furthermore, 3 pathogens (Campylobacter spp., L. monocytogenes and VTEC) were simultaneously identified in one bovine hide tested. In case of bovine carcasses 2 samples contained Campylobacter spp. and VTEC whereas one carcass was positive for L. monocytogenes and VTEC. On the other hand, 10 out of 362 (2.8%) minced beef samples were contaminated with at least two pathogens tested. The majority of these samples were contaminated with L. monocytogenes and Salmonella spp. (6 samples). It was noticed that equal number of C. jejuni and C. coli were found, irrespective of the origin of the samples. Most of the strains possessed more than one pathogenic factor as identified by PCR. Molecular serotyping of L. monocytogenes revealed that the majority of the isolates (27 out of 31; 87.1%) belonged to 1/2a serogroup. It was found that most of the VTEC isolates possessed the Shiga toxin stx2 gene (12 strains) whereas only 2 strains were str1-positive. The eneterohemolysin and intimin markers were identified only in 7 and 2 isolates, respectively. PCR analysis revealed that 4 VTEC belonged to O91 serogroup, 2 strains were O145 and 1 isolate was identified as O113. None of the VTEC detected in the study was O157 serogroup.     

Occurrences of thermophilic <Emphasis Type="Italic">Campylobacter</Emphasis> in pigs slaughtered at Morogoro slaughter slabs,Tanzania

Occurrences of thermophlic Campylobacter in pigs and pig carcasses was investigated in a cross-sectional study that was carried out in three selected slaughter slabs in Morogoro municipality, Tanzania. Before sampling, the slab hygiene, slaughter, carcass dressing, and meat handling was assessed. Fecal samples were collected from 66 slaughter pigs at the kill floor. After slaughter, a 100-cm² area on medial surface of the thigh muscles of dressed carcasses was sampled using sterile cotton swabs. Thereafter, the jejunal, cecal, and colon contents were also sampled. The samples were subjected to standard bacteriological examination using Skirrows protocol. In all slaughter slabs visited, it was found that pig slaughter, dressing, and meat handling was done on the ground under unhygienic condition. All the slaughter slab environment were dirty and had neither tap water or drainage systems. Thermophilic Campylobacter prevalence in slaughtered pig was 66.7% while contamination rate of dressed carcasses was 10.6%. Of the Campylobacter-positive carcasses, five (12.2%) were from the animals which were also positive to Campylobacter. The isolation rate of Campylobacter in the cecum was higher (34.8%) compared to the small intestines (28.8%) and colon (16.7%) although the difference was not statistically significant (P > 0.05). Campylobacter jejuni was the most prevalent species as it constituted 74% of all isolates, while Campylobacter coli was isolated at 26%. This suggests possible risks of infection to people through consumption of contaminated pork or through contact with infected pigs. Cecum was found to be the major part of intestine highly colonized by Campylobacter.     

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.     

Critical points in meat production lines regarding the introduction of listeria monocytogenes

Summary

In order to elucidate critical points concerning Listeria monocytogenes during bovine and porcine slaughter, cutting and processing, 843 samples were obtained from carcasses, primal cuts, products at retail and from environmental surfaces. Only 2–7% of the carcasses and 0–10% of the environmental samples in the ‘clean’ part of the pork slaughterline were found to be positive for L. monocytogenes. The incidence of L. monocytogenes was increased after chilling and cutting. In the cutting room 11–36% of the primal cuts and 71–100% of the environmental samples were found positive for L. monocytogenes. Our findings indicate that contamination of pork meat with L. monocytogenes orginates from the processing environment of the chilling or cutting room. The incidence of L. monocytogenes in the bovine cutting and meat processing line (0–60%) was lower than in the porcine cutting and meat processing line (11–100%).     

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 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)     

Estimation of Salmonella prevalence on individual-level based upon pooled swab samples from swine carcasses

Pooling of samples might be an effective means to increase cost-effectiveness in routine surveillance. The present study assessed the effect on the sensitivity of detection of Salmonella when pooling swab samples from swine carcasses compared to individual analyses. A total of 18,984 samples from nine Danish swine abattoirs were collected during 1 year, covering 2017 slaughter days. At each abattoir, swab samples were taken on a daily basis from 10 carcasses randomly selected. From each carcass, an area of 3 cm x 100 cm was swabbed. Five of these samples were analysed individually and the other five were analysed as one pooled sample. Standard culture methods were used. A logistic regression model was built, where the response was whether a sample was Salmonella positive or not. The explanatory factors were abattoir, type of sampling (individual or pooled sample), and season of year 2000 (four quarters). The odds ratio (OR) of the effect of type of sampling in the logistic model accounting for abattoir and season was interpreted as the conversion factor between pooled and individual sample prevalence. The results of the individually analysed samples showed a low prevalence of Salmonella (1.4%). When Salmonella was isolated, mostly only one positive sample was found among the five individually analysed samples per slaughter day. On a few days >1 positive samples' were found (9 out of 2017 days approximately 0.4%). The pooled sample prevalence was 4.1%. Because the individual prevalence was low, the pooled sample prevalence would have been around five times higher than the individual-level prevalence-if there had been no loss of sensitivity. However, we found that due to loss of sensitivity the pooled prevalence was only three times higher (OR = 2.7; CI 2.0-3.7). Therefore, a conversion factor of 3 instead of 5 should be applied to calculate the individual prevalence from a pooled prevalence. This approach has been used in the national surveillance of Danish pork since 2001. The estimated conversion factor and accept of pooling samples do not necessarily apply to a population with a higher prevalence or to other types of samples (e.g. faeces or lymph nodes) or diagnostic procedures.     

Campylobacter spp. in Irish Feedlot Cattle: A Longitudinal Study Involving Pre‐harvest and Harvest Phases of the Food Chain

The aim of this study was to investigate faecal shedding and transmission of Campylobacter spp. in cohorts of cattle within a feedlot, to assess subsequent contamination of carcasses with this pathogen and to identify risk factors associated with faecal shedding of Campylobacter spp. A cohort of 133 heifers housed in four adjacent pens was examined over a five and a half month period, from entering the feedlot to slaughter. A parallel investigation of individual rectal faecal samples and pen environmental samples were taken at monthly intervals from November to February. The entire outer and inner surfaces of a carcass side of each animal were swabbed immediately following slaughter. Campylobacter spp. were isolated from 322 (54%) of the 600 rectal faecal samples. Campylobacter jejuni and C. coli accounted for 69 and 29.7% of the isolate recovered, respectively. A total of 159 environmental samples were examined, of these Campylobacter spp. was isolated from 46 samples (29%). Campylobacter jejuni and C. coli accounted for 35 and 59% of these isolates, respectively. Campylobacter spp. was not isolated from any of the dressed carcasses. Logistic regression indicated prevalence of Campylobacter spp. faecal shedding within pens was positively correlated to the pen, the month of sampling and the Campylobacter spp. contamination status of the pen dividing bars and the water trough surface. Campylobacter spp. should be considered as a pathogen shed in the faeces of a substantial proportion of feedlot cattle. However, with good hygienic practice during harvest, a very low level of this pathogen can be achieved on dressed carcasses.     

Occurrence of Escherichia coli O157 in raw material and food in Czech Republic

The study was carried out to investigate the incidence of Escherichia coli O157 in raw materials, foodstuffs and the agricultural environment. Of a total of 987 samples examined, 22 strains (2.2%) were identified as E. coli O157 and 10 of them as E. coli O157:H7. Cefixime-Tellurite MacConkey sorbitol agar (CT-SMAC) agar and Biosynth culture medium (BCM) E. coli O157:7 medium were used for the isolation. The virulence factors (stx1, stx2, eae, and ehxA genes) were identified by polymerase chain reaction (PCR). Most strains were isolated from the mechanically deboned poultry meat (nine), minced meat (six) and raw milk (four). One strain was isolated from beef carcass and two strains from waste water. No strains were were found in mass for sausages, refreshment salads, swabs of pork and poultry carcasses and faeces of cattle and pigs. Ten strains from the 22 identified proved to be positive for all factors of virulence. They were isolated from minced meat (four), raw milk (four), waste water (one) and swab from beef carcass (one). Sensitivity to the antimicrobial drugs ampicillin (AMS), ampicillin-sublactam (SAM), tetracycline (TET), ofloxacine (OFL), cefuroxime (CRX), chloramphenicol (CPM), gentamicine (GEN), colistin (COL), cephalozine (CLZ), cefoxitin (CXT), aztreonam (AZT), and sulphamethoxazole + trimethoprim (COT) was tested using the standard dilution technique and disc diffusion test. Minimum inhibitory concentrations (MIC) characteristics (MIC(50), MIC(90), MIC range) and inhibitory zone diameter were determined for each strain. As determined by MICs, the resistance to tested antibiotics in E. coli O157 isolates was found to AMS (90.9%), CLZ (81.8%), CRX (63.6%), CXT (72.7%), CPM (72.7%), TET (81.8%), SAM (59.1%), COT (9.1%), COL (63.61%), AZT (9%) and GEN (4.5%). The similar results were obtained using the disc diffusion method. The differences were found relating to SAM, CXT, CMO and TET. Resistance against one or more antibiotics was found in 95.4% of E. coli O157. Only one strain was susceptible to all tested antibiotics. Most of the strains were resistant to ampicillin and cephalozine. Eight different resistance phenotypes were demonstrated in E. coli O157.     

Prevalences and transmission routes of Campylobacter spp. strains within multiple pig farms

In this work, faecal samples were collected from 15 pig farms to determine the Campylobacter prevalences at different times during the rearing period and to visualize the exchange of strains among the pig population by genotyping specific isolates. All isolated strains were identified as C. coli. Whereas no Campylobacter were detectable in the faeces of piglets at the day of birth, the Campylobacter incidence rose within days to 32.8%. After transfer to the nursery unit the prevalence increased to 56.6%. Approximately two-thirds of the pigs remained C. coli shedders in the fattening unit. In contrast to most farms, one farm expressed a very low Campylobacter incidence during the whole rearing period. Amplified fragment length polymorphism (AFLP) analysis was performed on all C. coli isolates of one farm. Clonal strains were identified from the brood sows and their offsprings or neighbouring piglets. After moving to the nursery unit, new genotypes appeared in that pig group but the original C. coli strains largely remained within that group. C. coli genotypes, identified during the fattening period, replaced the previously isolated genotypes. Transportation to the abattoir had no significant influence on the shedding rate of C. coli. The detection rate before transportation was 79.1% and decreased slightly to 78.2% (n=330). Additionally, eleven of 1474 environmental samples from different sources of the pig farms were positive for C. coli. This study demonstrates the importance of pigs as a reservoir for C. coli. Maternal C. coli strains are the primary source of infection but non-related genotypes from different sources appear during the rearing period and these latter strains constitute largely the final C. coli flora.     

A HACCP-based approach to hygienic slaughter and dressing of lamb carcasses

AIMS: This paper compares changes in visible and microbiological contamination on lamb carcasses dressed using one system which includes process factors previously identified as potential critical control points for HACCP-based approaches to hygienic slaughter and dressing, and another system which excludes those factors. METHODS: Longitudinal changes in microbiological and visible contamination of lamb carcasses were quantified in two slaughterhouses, one utilising clean, shorn, unwashed lambs in an inverted dressing system, the other utilising dirty, woolly, washed lambs in a traditional dressing system. Excision samples (5 cm2 each) for microbiological analyses were taken from two sites on 25 carcasses per treatment group immediately after pelting, at the completion of dressing, after overnight chilling and after boning and packaging. Visible contamination on the surface of 300 carcasses per treatment group was assessed after pelting and after overnight chilling. RESULTS: Mean aerobic plate counts and Escherichia coli counts on the leg and loin in the inverted dressing system were low after pelting (log10/cm2 1.86 and 1.71; log10/cm2 0.13 and 0.05 respectively) but generally showed statistically significant increases through to final packaging. In the conventional dressing system, there were much higher counts on the leg and loin after pelting (log10/cm2 4.66 and 2.71; log10/cm2 2.21 and 0.24 respectively), but subsequent handling of the carcass by slaughter line workers had no measurable deleterious effects. The inverted dressing system resulted in final mean aerobic plate counts on meat at packaging that were 1.38% (leg) and 48.98% (loin) of those derived from the conventional dressing system. Mean E. coli counts from the inverted system were 21.37% (leg) and 67.61% (loin) of those from the conventional system. There was an inverse relationship between the prevalence of carcasses with visible faecal contamination and their microbiological status. CONCLUSION: Significant reductions in microbiological contamination of sheep carcasses can be brought about by HACCP-based systems. Possible critical control points are pre-slaughter presentation status (including avoidance of pre-slaughter washing), inverted dressing, handling by slaughter line workers and meat inspectors, and chilling. Use of levels of visual faecal contamination as an on-line monitoring parameter for slaughter hygiene can give erroneous results. Interactions between different process steps may alter the effectiveness of the HACCP plan, and successful design and application depends on a detailed knowledge of the specific process utilised in each slaughterhouse.     

Prevalence of Salmonella in Ethiopian cattle and minced beef

To estimate the prevalence and distribution of Salmonella in the chain from cattle to the consumer, faeces, mesenteric lymphnodes and beef cuts from 235 cattle, stool samples from 300 workers of the same Addis Ababa abattoir, and 330 minced beef samples from supermarkets in Addis Ababa were analyzed. Isolated Salmonella strains were serotyped and tested for antibiotic susceptibility. Low prevalence in faeces and lymphnodes, and higher contamination rates of beef cuts (diaphragm, abdominal muscles) indicate severe cross-contamination during slaughter. Animals of poor health status were far more frequently carriers of salmonellae, which stresses the need of intensive ante-mortem inspection on slaughter animals. During transport from slaughterhouse to the supermarkets, production and selling of minced beef, the prevalence of Salmonella did not increase.     

Occurrence of salmonella in the ileum, ileocolic lymph nodes, tonsils, mandibular lymph nodes and carcasses of pigs slaughtered for consumption

This study evaluates the occurrence of Salmonella in pork carcasses and in some risk tissues (ileum, ileocolic and mandibular lymph nodes and tonsils), that can be involved in Salmonella contamination during slaughter. Salmonella was identified in 27 (26.7%) pigs and in 13 (12.9%) carcasses. From these positive carcasses, 69.2% presented the same serotype as that identified in the corresponding pig, which emphasize the pigs importance as a source of Salmonella during the slaughter, suggesting that measures should be taken at the level of pig production in order to reduce the slaughtering of Salmonella-positive animals. The highest value of Salmonella occurrence was reached in the ileocolic lymph nodes (18.8%) and in the ileum (13.9%), representing Salmonella potential faecal source during pork processing at the abattoir. In these samples, a high level of Salmonella was observed in the ileocolic lymph nodes in comparison with the ileum. The mandibular lymph nodes (12.9%) also presented a higher occurrence in comparison with the tonsils (9.9%). These results indicate that the lymph nodes analysis could be more sensitive in the detection of Salmonella than the closer drainage tissue. Otherwise, the presence of Salmonella in the lymph nodes indicates lymphatic spread of the organism, which reflects an increased risk of pork contamination. These results also indicate that, in order to achieve a better control of Salmonella contamination during the slaughter process, it is important to consider the improvement of the evisceration practices and the tonsils as well the extraction of mandibular lymph nodes after slaughter.