Assessment of bacterial superficial contamination in classical or ritually slaughtered cattle using metagenetics and microbiological analysis

Abstract

The aim of this study was to investigate the influence of the slaughter technique (Halal vs Classical slaughter) on the superficial contamination of cattle carcasses, by using traditional microbiological procedures and 16S rDNA metagenetics. The purpose was also to investigate the neck area to identify bacteria originating from the digestive or the respiratory tract. Twenty bovine carcasses (10 from each group) were swabbed at the slaughterhouse, where both slaughtering methods are practiced. Two swabbing areas were chosen: one "legal" zone of 1600 cm 2 (composed of zones from rump, flank, brisket and forelimb) and locally on the neck area (200 cm 2 ). Samples were submitted to classical microbiology for aerobic Total Viable Counts (TVC) at 30°C and Enterobacteriaceae counts, while metagenetic analysis was performed on the same samples. The classical microbiological results revealed no significant differences between both slaughtering practices; with values between 3.95 and 4.87 log CFU/100 cm 2 and 0.49 and 1.94 log CFU/100 cm 2 , for TVC and Enterobacteriaceae respectively. Analysis of pyrosequencing data showed that differences in the bacterial population abundance between slaughtering methods were mainly observed in the "legal" swabbing zone compared to the neck area. Bacterial genera belonging to the Actinobacteria phylum were more abundant in the "legal" swabbing zone in "Halal" samples, while Brevibacterium and Corynebacterium were encountered more in "Halal" samples, in all swabbing areas. This was also the case for Firmicutes bacterial populations (families of Aerococcaceae, Planococcaceae). Except for Planococcoceae, the analysis of Operational Taxonomic Unit (OTU) abundances of bacteria from the digestive or respiratory tract revealed no differences between groups. In conclusion, the slaughtering method does not influence the superficial microbiological pattern in terms of specific microbiological markers of the digestive or respiratory tract. However, precise analysis of taxonomy at the genus level taxonomy highlights differences between swabbing areas. Although not clearly proven in this study, differences in hygiene practices used during both slaughtering protocols could explain the differences in contamination between carcasses from both slaughtering groups.

Specific Time Determinism: Circadian Rhythm of Microbial Community Assembly Patterns Under Common Light in Feces of Laying Hens

“…The ubiquitous gram-positive bacterium Enterococcus is a symbiotic bacterium of the intestinal tract but can cause serious opportunistic infections [67][68][69]. The Planococcaceae family from the Firmicutes phylum accounts for 18% of the feces microbiota of cattle; therefore, it is considered a normal resident of the bovine gut and may be collected from viscera and carcasses [70,71]. Salinispora tropica, Burkholderia bryophila, and Enterococcus cecorum were the important bacteria in the feces microbiota; however, they did not play an important role in the network and were completely independent of the outside two clusters.…”

Current research and emerging tools to improve fresh red meat quality

“…Other genes, such as gyrB, have also been proposed for such studies to provide greater discriminatory potential (Poirier et al, 2018). Such studies have been used to examine the impact of various abattoir setups and practices (Stellato et al, 2016;Korsak et al, 2017) and the impact of storage and/or packaging conditions (Wang et al, 2016;Kaur et al, 2017). In some cases, such analysis has been undertaken with parallel analysis of metabolites such as volatile organic compounds to provide further understanding of spoilage (Mansur et al, 2019).…”

Metagenome‐based surveillance and diagnostic approaches to studying the microbial ecology of food production and processing environments

“…In Halal, slaughtered meat Corynebacteriaceae was detected in higher proportions than in classically slaughtered meat. Bacterial diversity was also higher in the Halal slaughtered meat (Korsak et al, 2017). The impact of processing on refrigerated pork sausages has also been investigated (Benson et al, 2014).…”