Type, areal extent and localization of carcass contaminations during industrial pig slaughter

The aim of the study is to provide an up-to date overall evaluation of visual contamination occurring on the slaughter line in order to provide a basis for implementing contamination control measures and to the hygienic quality of the processes. For this purpose, 627 contaminated pig carcasses in an industrial slaughterhouse in north western Germany were examined in 2021 for its distribution of type, areal extent and localization of slaughter contamination. Prior to official meat inspection, two persons visually scanned dorsal and ventral surfaces of the eviscerated but not yet split pig carcasses from cranial to caudal and recorded types, areal extent and localization of the contamination. The main contamination type were intestinal contents, bile, stomach contents, tubular rail fat and "others", which mostly consisted of a reddish foam from the respiratory tract. 103 out of 627 contaminated animals showed more than one contamination, which leads to a total number of 754 contaminations detected. Intestinal contents accounted for almost half of all contaminations and "others" for 30%. Forelimb, back and ham together counted for 70% of the contaminated regions. The affected area was smaller than that of a one euro coin (diameter about 23 mm) in 86% of the cases.

A Review of Slaughter Practices and Their Effectiveness to Control Microbial - esp. Salmonella spp. - Contamination of Pig Carcasses

The BIOPIGEE project (part of the One Health European Joint Programme under Horizon 2020) aimed to identify relevant measures to effectively control Salmonella, and another zoonotic pathogen, hepatitis E virus (HEV) within the pig meat food chain. The aim of this study was to identify biosecurity measures or management practices that are relevant for limiting Salmonella and/or HEV occurrence and spread within pig slaughterhouses. This was with the final goal of compiling a list of biosecurity measures for different processes and operations along the slaughter line with evidence of their effectiveness. To achieve this, a literature review was conducted on studies estimating the effectiveness of measures applied in slaughterhouses to reduce the microbial contamination of pig carcasses. Results of this literature search are discussed and presented in summary tables that could be used as a source of information for the pig slaughter industry to further develop their guidelines on hygienic slaughter.

Intact gastro-intestinal tract removal from pig carcasses in a novel Meat Factory Cell approach

Conventional automated slaughter lines for pigs are organised as disassembly lines with many specialised machines. High costs and capacities make them relevant only for large scale meat production. The ambition with the novel Meat Factory Cell (MFC) concept is to provide the meat industry with a robust and flexible automation platform that is also relevant for smaller scale production. The MFC process deviates radically from conventional processing of pig carcasses after singeing. In MFC, the limbs are removed first. Then the dorsal muscles along the spinal axis from tail to head are removed with the column and rind in one meat cut, followed by removal of the viscera. Finally, the cut ribs and belly are removed. Such approaches to automation in pig abattoirs and cutting plants are highly needed in smaller scale production, and they should produce meat and offal as hygienically as conventional factories. This case study reports the evisceration of 37 pigs in 9 trials performed in 2019. Several approaches were tested with a prototype carcass holding unit. Evisceration could be undertaken without the need to cut through the gastrointestinal tract from tongue to rectum, reducing the probability of accidental faecal contamination of pork carcasses from the gut content. The Meat Factory Cell procedure is an advance towards automated evisceration of pig carcasses which is both simple and hygienic. The traditional separation of internal organs into a pluck set and a set of stomach and bowels was more prone to leakages.

A comparison of fluctuations of Campylobacter and Escherichia coli concentrations on broiler chicken carcasses during processing in two slaughterhouses

The causes of differences in Campylobacter and Escherichia coli concentrations on broiler chicken carcasses after chilling between slaughterhouses are not fully identified. Therefore, it is a challenge for slaughterhouses to comply with Process Hygiene Criteria for broiler meat. The aim of the study was to identify which processing steps contribute to increases or decreases in Campylobacter and E. coli concentrations within and between two slaughterhouses. Identifying the processing steps with variable performance could explain the differences in bacterial concentrations after chilling between slaughterhouses. Thermotolerant Campylobacter and E. coli concentrations on carcasses during broiler processing were measured during the summer period in 21 trials after bleeding, scalding, defeathering, evisceration and chilling. In two slaughterhouses with comparable Campylobacter and E. coli concentrations in the incoming batches (after bleeding), the mean log10 concentrations are found to be significantly different after chilling. Campylobacter concentrations decreased by 1.40 log10 in Slaughterhouse 1 and by 1.86 log10 in Slaughterhouse 2, whereas E. coli decreased by 2.19 log10 in Slaughterhouse 1 and by 2.84 log10 in Slaughterhouse 2. Higher concentrations of Campylobacter and E. coli on carcasses after chilling were observed in Slaughterhouse 1 in which an increase in concentrations was observed after evisceration. The effect of processing on Campylobacter and E. coli concentrations in Slaughterhouse 1 did not differ between batches. In Slaughterhouse 2, the effect of processing on the concentrations of both bacteria varied over batches. Changes in E. coli concentration levels during processing were similar to Campylobacter except for defeathering. E. coli concentration significantly decreased after defeathering in both slaughterhouses, whereas Campylobacter increased in Slaughterhouse 2 and in Slaughterhouse 1 no significant changes were observed. The patterns of increases and decreases in bacterial concentrations during processing are specific for each slaughterhouse. Inhomogeneous patterns potentially explain the differences in concentrations after chilling between slaughterhouses. Critical processing steps should be validated in each slaughterhouse by longitudinal studies and potentially based on E. coli. E. coli has a potential to be used as an indicator of processing hygiene, because the impact of most of the studied processing steps was similar as for Campylobacter.

Effects of hygienic treatments during slaughtering on microbial dynamics and contamination of sheep meat

The aims of this study were to investigate bacterial dynamics in the sheep meat chain, from fleece to meat trimmings, using both quantitative and qualitative analyses, and to study the effects on microbial load associated with the hygienic interventions of: i) shearing sheep immediately before slaughter, ii) manual steam vacuum pasteurisation, iii) hot water pasteurisation of carcasses, followed by iv) chilling. A further aim was to provide evidence to determine whether or not unshorn sheep should be handled in a processing line separate from that of shorn sheep in Norwegian abattoirs. A total of 176 surface swab samples were collected from three sites along the value chain: i) on fleeces, ii) on carcasses at the end of the slaughter line, and iii) on carcasses after chilling for 24h, and 32 samples were collected from meat trimmings. The results showed that Aerobic Plate Counts (APC) were lower for the shorn group compared to the unshorn group, both on carcasses before chilling and after chilling (difference of 0.8 and 0.9logCFU/1000cm(2) (p≤0.05), respectively) and in meat trimmings (difference of 0.5logCFU/g (p≤0.05)). Hygienic treatments were used on carcasses derived from unshorn sheep, and steam vacuum treatment reduced Escherichia coli, Enterobacteriaceae, and APC before chilling by 1.2, 1.0, and 0.6logCFU/1000cm(2) (p≤0.05), respectively, and hot water pasteurisation, in addition to chilling, reduced E. coli, Enterobacteriaceae, and APC by 0.7, 1.0, and 0.9logCFU/1000cm(2) (p≤0.05), respectively, compared with untreated carcasses. The effect of chilling was shown by the significant reduction of number of carcasses where E. coli were detected; from 65% (13/20) of the shorn group before chilling to 35% (7/20) after chilling, and from 90% (36/40) to 45% (9/20) of the unshorn group. Sequencing of the 16S rRNA gene derived from 316 colonies of Enterobacteriaceae showed a tendency for the relative proportion of the genus Escherichia/Shigella, compared with other genera within Enterobacteriaceae, to be greater for unshorn, untreated sheep than from the other groups at the sampling locations along the meat chain. The study showed that steam vacuum and hot water pasteurisation reduced the contamination of carcasses derived from unshorn sheep, down to the level of the shorn group, and thus can replace the separate processing line for unshorn sheep. Indeed, the low microbial contamination in meat trimmings for all groups indicates that the separate processing line is unnecessary.