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.     

Effect of boiling water carcass immersion on aerobic bacteria counts of poultry skin and processed ground poultry meat

This study was conducted to determine the relationship between bacteria destruction on poultry carcass skin and bacteria in raw ground poultry meat from the same carcasses. Immersion time in boiling water of broiler chicken whole carcasses required for maximum reduction of naturally occurring aerobic bacterial count on skin was measured. Treatments for chicken carcasses consisted of immersion in boiling water (approximately 95 degrees C) for 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, and 4 min. Four skin samples taken following treatment and three taken from subsequently ground carcass meat were analyzed for total aerobic plate counts (APC). Analysis of the data indicated a linear increase in bacterial destruction on skin with increased boiling water immersion time from 0 to 4 min. Reduction of skin bacteria to less than 1 log10 occurred at 3 min carcass immersion or longer. The analysis also indicated that treatment with boiling water and removal of skin was effective in reducing bacterial counts in ground meat to similar levels at all treatment times from 0.5 to 4.0 min. Findings from this study indicated that a boiling water immersion intervention and removal of skin could reduce subsequent bacteria contamination of ground meat. This intervention could minimize the risk of pathogen-contaminated primary processed poultry carcasses used in further processing.     

Shearing male lambs in the cold season improves the carcass yield without affecting fattening performance

This research was carried out to determine the effects of shearing of different genotypes of male lambs (one from pure Karayaka stock and two from its crossbreed) in winter on bodyweight gain, feed consumtion, feed conversion efficiency, rectal temperature and carcass yield. A total of 21 lambs aged 8 months were allocated randomly to experimental groups according to a 2 × 3 factorial arrangement for shorn and unshorn animals. The lambs were fed grass hay (100 g/lamb/day) and commercial concentrate feed ad libitum during a 54‐day of fattening period. The lambs were shorn in the middle of the experiment (27 days after beginning the trial). The interaction between the shearing treatment × genotype of the studied parameters was found to be insignificant. The shearing process increased the rectal temperature (P < 0.01), hot carcass yield (P < 0.05) and dressing percentage (P < 0.05) and decreased the weight of the edible inner organs (P < 0.01). Some of these parameters were affected by the genotypes. It was concluded that shearing male lambs in the winter can have a beneficial effect on the hot carcass weight and dressing percentage without affecting fattening performance, and the performance of Karayaka lambs and its crossbred male lambs were similar under the conditions of the present study.     

Prevalent organisms on ostrich carcasses found in a commercial abattoir

The prevalent microbial growth on carcasses before and after overnight cooling in an ostrich abattoir and de-boning plant was investigated. The effect of warm or cold trimming of the carcasses was examined together with possible causes of contamination along the processing line. An attempt was made to link the prevalent microorganisms that were identified from carcasses to those from specific external contamination sources. Samples of carcasses and possible contaminants were collected in the plant, plated out and selected organisms were typed using a commercial rapid identification system. It was indicated that the cold trim (mainly of bruises) of carcasses was advantageous in terms of microbiological meat quality. Results indicated pooled water in the abattoir as the most hazardous vector for carcass contamination and that contaminants from this source are mostly Gram-negative pathogens. Pseudomonas and Shigella were frequently isolated from surface and air samples and indicated that the control of total plant hygiene is a requirement for producing ostrich meat that is safe to consume and has an acceptable shelf-life.     

The use of neck skin for microbial process control of fresh poultry meat using the bioluminescence method

In this study comparative investigations of the total viable counts of bacteria and viable counts of Enterobacteriaceae with the ATP content were carried out on 70 poultry carcasses and neck skins thereof. The results revealed a correlation of total viable counts on the neck skin and on the carcass sample. Therefore the examination on total viable counts of neck skin is able to give results on the respective load of the carcass (coefficient of correlation (r) = 0.85 and coefficient of determination (R2) = 0.71). This only applies, however, to a slaughter technology at which the poultry hangs up site down with the neck skin to the bottom. The results of the ATP investigation expressed in Relative Light Units (RLU) in a bioluminescence method and total viable counts of neck skin samples are correlated (r = 0.85; R2 = 0.72). Lower values for r and R2 were estimated for RLU/Enterobacteriaceae on neck skin (r = 0.64; R2 = 0.41), for RLU/total viable counts on the carcass (r = 0.66; R2 = 0.46) and for RLU/Enterobacteriaceae on the carcass (r = 0.33; R2 = 0.11). To estimate the hygiene status in poultry slaughtery, sampling from the neck skin can replace the sampling on the whole carcass The bioluminescence method is suitable to replace the determination of total viable counts in the context of in-house hygiene supervision. However, this method seemed to be less reliable to predict the Enterobacteriaceae counts.     

Effects of age, castration, and season on difficulty of pelt removal in lambs

Sixty-four white-faced rams and wethers were dressed with the aid of a commercial pelt puller. The effects of age, castration, and season on difficulty of pelt removal and pelt damage were evaluated. Lambs were divided into two age groups (5 and 12 mo) within gender (ram and whether) and season (spring and fall). A greater force (P less than .05) was required to remove pelts from rams than from wethers in both 5- and 12-mo-old groups. Older lambs slaughtered in the fall required more force (P less than .05) to remove their pelts than did those slaughtered in the spring, but differences by season did not exist for 5-mo-old lambs. The difference between rams and wethers in percentage of live weight that was closely shorn pelt weight was not significant (P greater than .05). The area of grain crack in the flank expressed as a percentage of total area of the skin was lower (P less than .05) for skins from 5-mo-old lambs and ram lambs than it was for skins from 12-mo-old lambs and wether lambs, respectively. Factors involved in difficulty of pelt removal in ram lambs included crosscut shoulder weight, fat firmness, and carcass weight. Difficulty of pelt removal in wether lambs was best predicted by including crosscut shoulder weight and bodywall thickness in multiple regression equations.     

The effect of different bird washers on the microbiological quality of broiler carcasses

Summary

The effect of spray washers and inside‐and‐outside bird washers on the microbiological quality of broiler carcasses was examined in 13 poultry slaughterhouses. The carcasses were sampled by means of the carcass rinse method; total and Enterobacteriaceae counts were estimated. The decrease in total and Enterobacteriaceae counts due to spray washing was as high as with the use of an inside‐and‐outside bird washer. From this investigation the conclusion can be drawn that the use of an inside‐and‐outside bird washer does not guarantee a better microbiological cleaning of the inside of the carcasses made ‘mandatory’ by EEC regulations.     

Microbiological aspects of poultry processing

The microbiological condition of poultry carcasses is shown to be influenced by the general hygiene in the processing plant which is largely determined by (i) the quality of the raw materials, (ii) the design of plant and buildings, (iii) personal hygiene and (iv) cleaning efficiency. The standard of hygiene is dealt with under (i) assessment of contamination on surfaces, (ii) estimation of contamination on carcasses, including bacteria of public health significance and (iii) other measurements of value. Microbiological sampling of surfaces and carcasses is discussed and standards are suggested for water supplies, surfaces and carcasses. Data are presented from 430 frozen eviscerated carcasses sampled over the period of 12 months from a large processing plant.     

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.     

Elimination of Salmonella spp. by lactic acid

The aim of the present study was to determine the elimination of Salmonella by different lactic acid concentrations in microbiological media and on turkey carcass elements. The average bacteria counts in the control samples without lactic acid were: 1.8 x 10(8), 1.1 x 10(8) and 2.3 x 10(8), for S. Enteritidis, S. Anatum and S. Typhimurium, respectively. The concentration of lactic acid of 0.1% in the agar media completely inhibited the growth of all Salmonella strains. At 0.05% lactic acid concentration, the bacteria count was 2 log cycles lower and at a 0.03% solution it was 1 log cycle lower than that in the respective control samples. However, the examined bacteria developed in the presence of 0.02% and 0.01% lactic acid concentrations and their counts fell into the same log brackets. An analysis of the experimental results obtained from turkey carcass elements immersed in the lactic acid solution showed that the Salmonella identification rate was determined by the bacteria inoculum spread over the turkey carcass surface. The contamination of 10(1) CFU of Salmonella spread onto the turkey carcass was completely eliminated by immersing the carcasses in 1% or 2% lactic acid solutions. The contamination of turkey carcass elements with 10(2) CFU of S. Enteritidis and their immersion in 2% lactic acid solution for 15 min resulted in the reduction of the number of samples with Salmonella compared to the number of control samples with Salmonella. At contaminations of 10(3) CFU on the carcass surfaces, the immersions in 1% and 2% lactic acid solutions did not reduce Salmonella counts.     

Distribution and genetic characterization of porcine Campylobacter coli isolates

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

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)     

Capacity building: benchmark for production of meat with low levels of bacterial contamination in local slaughterhouses in Somaliland

The objective of the study was to investigate and assess the impact of trainings on the levels of meat contamination produced from local livestock slaughter facilities in the North-West region of Somalia (Somaliland). The investigation considered slaughter facilities where workers had been trained or not. The survey was carried out in four local slaughter facilities. A pre-tested questionnaire on abattoir hygiene and food safety standards was administered to International Aid Organizations, government officials, abattoir workers and supervisors. In addition, a total of 320 surface meat swab samples were collected from randomly selected small ruminant carcasses slaughtered from four purposefully selected local slaughter facilities. The samples were analyzed at Analabs laboratories in Nairobi, Kenya, for total viable counts, total coliforms count and presence of Salmonella species. Meat contamination risk factors associated with hygiene practices based on training offered or not was identified. It was noted that slaughter facilities where abattoir workers had not received trainings on minimum meat hygiene standards and quality assurance systems of good hygiene practices and sanitary standard operating procedures produced carcasses with high levels of bacterial contamination in comparison with those where workers had received the said trainings. The laboratory results were in agreement with poor hygiene meat handling practices and lack of compliance with minimum meat hygiene and food safety standards in Berbera and Burao local livestock slaughter facilities where personnel had not been trained.     

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.     

Effect of spray-chilling on quality of beef from lean and fatter carcasses

Carcasses from five trim cows and five choice steers were used to study the effects of spray-chilling on cooler shrink, chill rate, purge loss from vacuum-packaged cuts, cook loss, shear values and bacterial growth. Spray-chilling reduced cooler shrink but had no effect on chill rate, purge loss from vacuum-packaged cuts, cook loss or shear values. Aerobes, facultative anaerobes, aerobic psychrotrophs, facultative anaerobic psychrotrophs and lactic acid bacteria all tended to be higher on rounds from spray-chilled sides. Leaner (and lighter) cow carcasses chilled faster and had lost a higher percentage of their weight at 24 h than fatter and heavier steer carcasses. The leaner carcasses had higher bacterial counts initially and throughout storage. This difference may have been due to differences in the level of initial contamination during dressing and not due to the carcasses' leanness. Purge-weight loss for each carcass increased and cooking weight loss decreased with increased storage times, making the total weight loss from meat aged 5 vs 10 wk similar.     

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

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

Microbiological evaluation of groups of beef carcasses: heifers and steers.

Numbers of mesophilic bacteria were estimated on carcasses of 25 heifers and 25 steers of beef breeds in a modern, high-line-speed abattoir. One side of each carcass from each sex was sampled at the end of the kill-floor, before the carcass wash, on each of 25 visits. Two adjacent excision samples (5 x 5 x 0.5 cm) were taken from each of ten sites and processed for automatic enumeration of aerobic bacteria on hydrophobic grid membrane filters. The effects of sex and carcass weight on bacterial counts were examined. Groups of carcasses were examined to determine the sample size required for future assessments of kill-floor hygiene. The log10 of the most probable number of growth units (MPNGU)/cm2 did not differ significantly between heifers and steers (average over the ten sites of 2.2) and there was no effect of carcass weight on bacterial counts for nine of the ten sites. There were, however, highly significant (p < 0.001) differences in the counts between sites and the counts from the ten sites clustered into five homogenous groups. The between-carcass component of variation at a site was generally larger than the within-carcass component. We conclude that, to estimate the mean log10 MPNGU/cm2 at a site to within +/- 0.5 units, future group-carcass evaluations require about 200 samples from 10 (two adjacent samples/site) or 20 carcasses (one sample/site).     

Pilot field trial of a recombinant Taenia ovis vaccine in lambs exposed to natural infection

Previous trials of an experimental Taenia ovis vaccine using the recombinant antigen GST--45W(B/X) established that it was possible to achieve >90% protection against a single artificial challenge of T. ovis eggs. This trial was undertaken to assess vaccine efficacy against artificial challenge and natural infection acquired by lambs grazing contaminated pasture. Two hundred Romney lambs were vaccinated at 6 and 12 weeks of age. One hundred control lambs were not vaccinated but were allowed to run with the vaccinated mob. At 15 weeks of age, 10 controls and 18 vaccinated lambs were artificially challenged with 2000 T. ovis eggs. The remaining control and vaccinated lambs were allowed to graze contaminated pasture for 3 weeks and were then moved to clean pasture for 5 months. The artificially challenged lambs plus 24 of the field-infected lambs were slaughtered and the carcasses dissected to obtain cyst counts. The remaining field-infected lambs were slaughtered at a commercial processing plant and the carcasses examined by conventional meat inspection. The results showed that the vaccine provided a high level of protection against artificial challenge (92%) and natural infection (98%) when assessed by carcass dissection. The data from commercial meat inspection showed that vaccination provided 89% efficacy against downgrading or condemnation compared to non-vaccinated control lambs. The average difference in carcass values between vaccinated and non-vaccinated groups was 4.36 dollars, representing a 35% loss in value due to T.ovis infection in non-vaccinated lambs.     

Implementation of a validated HACCP system for the control of microbiological contamination of pig carcasses at a small abattoir

To guide the implementation of a Hazard Analysis Critical Control Point (HACCP) system at a small abattoir, the microbiological conditions of pig carcasses at various stages of processing were assessed by enumerating total aerobes, coliforms, and Escherichia coli in samples collected from randomly selected sites on the carcasses. Those data indicated that carcasses were contaminated with bacteria mainly during dehairing and operations on the head. When carcasses were pasteurized after head removal, the numbers of total aerobes on dressed carcasses were reduced by about 1 order and the numbers of coliforms and E. coli were reduced by more than 2 orders of magnitude. Implementation of an HACCP system on the basis of the microbiological data gave cooled carcasses with mean numbers of total aerobes < 100/cm2, and mean numbers of coliforms and E. coli about 1/1000 cm2.     

Effect of Sand and Shaking Duration on the Recovery of Aerobic Bacteria,Coliforms, and Escherichia coli from Prechill Broiler Whole Carcass Rinsates

Broilers entering a processing facility can be contaminated with bacteria internally, externally, or both, and additional contamination may occur during processing. Although processing generally reduces the bacterial load on a carcass, it does not eliminate all carcass bacterial contaminants. Processing plant personnel sample carcasses daily to determine overall carcass contamination using the whole carcass rinse procedure. The objective of this study was to evaluate the potential benefit of adding sand to the whole carcass rinse and extending shaking (rinsing) duration on the recovery of bacteria from broiler carcasses. Eviscerated broiler carcasses were obtained from a commercial processing plant before the prechill final wash. Carcasses were rinsed in peptone or peptone with sand for 1 and 4 min. Rinsates were analyzed for aerobic plate count, coliforms, and Escherichia coli. Bacterial levels recovered from rinsates with sand were significantly higher than levels recovered from the peptone-only rinsates, but the increase in recovery was relatively small at 0.6 log₁₀ cfu/mL of rinsate. There was no significant improvement in bacterial recovery when shaking duration was increased from 1 to 4 min for either rinse treatment.