Upright versus inverted catching and crating end-of-lay hens: a trade-off between animal welfare, ergonomic and financial concerns.

This study explores upright versus inverted catching and crating of spent laying hens. Both catching methods were compared using a cost-benefit analysis that focused on animal welfare, ergonomic, and financial considerations. Data were collected on seven commercial farms (one floor system and six aviary systems) during depopulation of approximately 3,000 hens per method per flock. Parameters such as wing flapping frequency, catcher bird interaction, incidence of catching damage and hens dead on arrival (DOA) were measured and compared between catching methods. Ergonomic evaluations were performed via catcher surveys and expert assessment of video recordings. The wing flapping frequency was lower (3.1 ± 0.6 vs. 4.0 ± 0.5, P < 0.001) and handling was gentler (1.9 ± 0.5 vs. 4.4 ± 0.5, P < 0.001), both on a 7-point Likert scale, for upright versus inverted catching. However, more person-hours per 1000 hens were required for upright than inverted catching (8.2 ± 3.2 h vs. 4.8 ± 2.0 h, P = 0.011), with only wing bruises being significantly less common for upright than inverted catching (1.1 ± 0.6 % vs. 1.7 ± 0.7%, P = 0.04). Upright catching was 1.8 times more expensive than inverted catching; compensation for this cost would require a premium price of approximately €0.0005 extra per egg. Ergonomically, both catching methods were considered demanding, although catchers (n = 29) preferred inverted catching. In conclusion, this study showed animal welfare benefits of upright vs. inverted catching. Industry adoption of upright catching will depend on compensation of the additional labor costs, adjustments to labor conditions and shorter loading times.

Intra- and inter-batch variability in raw pork challenge test studies and their consequences on model predictions: An intricate interplay between L. monocytogenes, the microbiome, and packaging atmosphere.

The purpose of this study was to conduct challenge studies in raw pork by strictly following all aspects of the 2014 EURL technical guidance document for conducting shelf-life studies on Listeria monocytogenes. Growth potential was assessed on three batches of self-cut pork chops and one batch of in-house prepared pure minced pork without any additives in air and MAP (70 % O2/30% CO2) packaging. Pork chops did not support the growth of the pathogen throughout the shelf-life, given the specific conditions used in this study, with growth potential values of 0.28 and 0.46 log CFU/g, respectively, for both air and MAP. Substantial growth (>0.5 log CFU/g) was obtained in minced pork after investigating only one batch, with growth potential values of 1.69 and 0.80 log CFU/g, for air and MAP. However, both intra- and inter-batch variability for pork chops and intra-batch variability for minced pork was observed; with elevated growth being evened out by the way growth potential is calculated in the EURL 2014 document, leading to underestimations and posing a potential risk to public health. Maximum growth rate in minced pork at a constant temperature of 7 °C was estimated at µmax = 0.680 log CFU/day and µmax = 0.489 log CFU/day in air and MAP, respectively. Model predictions for the growth potential showed acceptable results for air-packed minced pork with better accuracy when the lag phase was implemented as indicated in the renewed protocol (CRL EU, 2021). In MAP, all models used, including the Combase Growth model and to a lesser extent the DMRI dynamic safety model, overestimate the growth potential probably due to a lack of integration of the changing CO2 levels in the packages. The predictive models used in this study do not adequately account for the dynamics in the raw pig matrix, which may have an inhibitory effect on the growth of L. monocytogenes, including interaction with the microbiome and CO2, and emphasize the importance of remaining critical of predictive model outcomes. In addition, the experimental intra- and inter-batch variability raise questions about the sense or nonsense of using predictive microbiology in these raw pork products.

Genetic Listeria monocytogenes Types in the Pork Processing Plant Environment: From Occasional Introduction to Plausible Persistence in Harborage Sites.

The purpose of this study was to investigate the L. monocytogenes occurrence and genetic diversity in three Belgian pork cutting plants. We specifically aim to identify harborage sites and niche locations where this pathogen might occur. A total of 868 samples were taken from a large diversity of food and non-food contact surfaces after cleaning and disinfection (C&D) and during processing. A total of 13% (110/868) of environmental samples tested positive for L. monocytogenes. When looking in more detail, zone 3 non-food contact surfaces were contaminated more often (26%; 72/278) at typical harborage sites, such as floors, drains, and cleaning materials. Food contact surfaces (zone 1) were less frequently contaminated (6%; 25/436), also after C&D. PFGE analysis exhibited low genetic heterogeneity, revealing 11 assigned clonal complexes (CC), four of which (CC8, CC9, CC31, and CC121) were predominant and widespread. Our data suggest (i) the occasional introduction and repeated contamination and/or (ii) the establishment of some persistent meat-adapted clones in all cutting plants. Further, we highlight the importance of well-designed extensive sampling programs combined with genetic characterization to help these facilities take corrective actions to prevent transfer of this pathogen from the environment to the meat.

Study of the transfer of Listeria monocytogenes during the slaughter of cattle using molecular typing.

The introduction, transmission, and persistence of Listeria monocytogenes in Belgian beef slaughterhouses was investigated using genetic characterization. During slaughter, samples were taken of the hide, carcass, and environment to detect the pathogen. Remarkably, L. monocytogenes was massively present on the hide of incoming animals (93%; 112/120), regardless of their visual cleanliness, which implies high contamination pressure levels entering the slaughterhouses. Pathogen transfer via cross-contamination was conclusively confirmed in this study, with the same pulsotypes isolated from the hide, carcass, and environmental samples. Despite the important bacterial presence on the hide of incoming animals, most slaughterhouses succeeded in limiting the transfer as cause of carcass contamination. Persistence along the slaughter line seemed to be a more significant problem, as it was clearly linked to most of the L. monocytogenes positive carcasses. In one slaughterhouse, whole genome sequencing (WGS) revealed that the carcass splitter had been contaminating carcasses with the same strain belonging to CC9 for more than one year.