Individual effect of the steps preceding slaughtering on Salmonella contamination of pigs

The influence of the different steps preceding pig slaughtering (waiting in the herd, transport and lairage) was studied regarding deep (organs) and surface (carcass) Salmonella contamination, by mixing SPF with contaminated pigs at the different steps. For a lairage of 2 hours and a transport of 1 hour, the caecal contamination concerned the conventional pigs and the long time mixed groups (more than lairage time). The isolated strains were from herd origin according to serotyping. After the slaughtering process, it was not possible to differentiate carcasses contamination rate for the conventional batch from those of the control group pigs (transport and lairage in Salmonella-free conditions). This study showed that without efficient control measures during slaughtering, implementation of control measures in the herd would be inefficient regarding carcass contamination rate

Identification and distribution of E. coli virulence gene profiles in an operating swine production network

A number of studies have demonstrated a link between the detection of potentially pathogenic Escherichia coli strains and economic loss in the swine industry. E. coli strains belong to different commensal or pathogenic clonal groups, the latter being characterized by the presence of specific virulence genes

Reduction of Salmonella Shedding by Sows during Gestation in Relation to Its Fecal Microbiome

International audiencePork meat is estimated to be responsible for 10-20% of human salmonellosis cases in Europe. Control strategies at the farm could reduce contamination at the slaughterhouse. One of the targeted sectors of production is maternity, where sows could be Salmonella reservoirs. The aim of this study was to assess the dynamics of shedding of Salmonella in terms of variation in both shedding prevalence and strains excreted during gestation in Quebec's maternity sector. The evolution of the fecal microbiota of these sows during gestation was also assessed to detect bacterial populations associated with these variations. A total of 73 sows both at the beginning and the end of the gestation were randomly selected and their fecal matter was analyzed. Salmonella detection was conducted using a method that includes two selective enrichment media (MSRV and TBG). Nine isolates per positive samples were collected. Among the 73 sows tested, 27 were shedding Salmonella. Sows in the first third of their gestation shed Salmonella significantly more frequently (21/27) than those in the last third (6/46) (χ2P < 0.05). The shedding status of 19 of the sows that were previously sampled in the first third of their gestation was followed, this time in the last third of their gestation, which confirmed reduction of shedding. Using 16S rRNA gene sequencing and qPCR, significant differences between the fecal flora of sows at the beginning and the end of the gestation, shedding Salmonella or not and with different parity number were detected. Using MaAsLin, multiple OTUs were found to be associated with the time of gestation, the status of Salmonella excretion and parity number. Some of the identified taxa could be linked to the reduction of the shedding of Salmonella at the end of gestation. In this study, we showed that the level of Salmonella shedding was variable during gestation with significantly higher shedding at the beginning rather than at the end of gestation. We also observed for the first time a significant change in the microbiota during sow gestation and identified interesting taxa which could be linked to a reduced Salmonella shedding

Assessment of the efficiency of ozonated water as bacterial contamination reduction tool in a pork cutting plant

The food industry is constantly searching for new tools to reduce bacterial contamination in the plants. In this study we assessed the efficiency of ozonated water as a tool to improve reduction of residual bacterial contamination in a pork cutting plant as a complement of sanitation procedures. First, the effectiveness of the ozonated water was tested on conveyors to reduce residual Salmonella, coliforms and aerobic flora load

Survival in water of Campylobacter jejuni strains isolated from the slaughterhouse

Campylobacter jejuni cause gastroenteritis in humans. The main transmission vector is the consumption or handling of contaminated chicken meat, since chicken can be colonized asymptomatically by C. jejuni. However, water has been implicated as the transmission vector in a few outbreaks. One possibility is the contamination of water effluent by C. jejuni originating from chicken farm. The ability of C. jejuni to be transmitted by water would be closely associated to its ability to survive in water. Therefore, in this study, we have evaluated the ability of reference strains and chickenisolated strains to survive in water. Defined water media were used, since the composition of tap water is variable. We showed that some isolates survive better than others in defined freshwater (Fraquil) and that the survival was affected by temperature and the concentration of NaCl. By comparing the ability of C. jejuni to survive in water with other phenotypic properties previously tested, we showed that the ability to survive in water was negatively correlated with autoagglutination. Our data showed that not all chicken isolates have the same ability to survive in water, which is probably due to difference in genetic content

Chicken Caecal Microbiome Modifications Induced by Campylobacter jejuni Colonization and by a Non-Antibiotic Feed Additive

[À l'origine dans / Was originally part of : Fac. Méd. vétérinaire - Chaire de recherche en salubrité des viandes]Campylobacter jejuni is an important zoonotic foodborne pathogen causing acute gastroenteritis in humans. Chickens are often colonized at very high numbers by C. jejuni, up to 109 CFU per gram of caecal content, with no detrimental effects on their health. Farm control strategies are being developed to lower the C. jejuni contamination of chicken food products in an effort to reduce human campylobacteriosis incidence. It is believed that intestinal microbiome composition may affect gut colonization by such undesirable bacteria but, although the chicken microbiome is being increasingly characterized, information is lacking on the factors affecting its modulation, especially by foodborne pathogens. This study monitored the effects of C. jejuni chicken caecal colonization on the chicken microbiome in healthy chickens. It also evaluated the capacity of a feed additive to affect caecal bacterial populations and to lower C. jejuni colonization. From day-0, chickens received or not a microencapsulated feed additive and were inoculated or not with C. jejuni at 14 days of age. Fresh caecal content was harvested at 35 days of age. The caecal microbiome was characterized by real time quantitative PCR and Ion Torrent sequencing. We observed that the feed additive lowered C. jejuni caecal count by 0.7 log (p<0.05). Alpha-diversity of the caecal microbiome was not affected by C. jejuni colonization or by the feed additive. C. jejuni colonization modified the caecal beta-diversity while the feed additive did not. We observed that C. jejuni colonization was associated with an increase of Bifidobacterium and affected Clostridia and Mollicutes relative abundances. The feed additive was associated with a lower Streptococcus relative abundance. The caecal microbiome remained relatively unchanged despite high C. jejuni colonization. The feed additive was efficient in lowering C. jejuni colonization while not disturbing the caecal microbiome

Digestive microbiota changes during application of an effective, feed presentation based, mitigation option against Salmonella shedding in pigs

If some studies have attempted to mitigate the Salmonella spp. excretion in pigs by feed related interventions, none clearly demonstrated the impact of the presentation (mash or pellet and particular size). Thus this study aimed to determine if the modification of the pigs feed presentation alone can lower the Salmonella spp. excretion

Isolation and characterisation of Listeria monocytogenes from piggeries in France

Recent analyses of human listeriosis outbreaks showed that these were associated with consumption of delicatessen items or pork products from other sources

Effect of fumonisins and Salmonella on digestive flora profiles assessed using a molecular tool (CE-SSCP).

Fumonisins (FB) are mycotoxins frequently found in vegetal feedstuffs, especially in maize used for pig feeding. Among fumonisins, FB1 was the better described toxin. It caused pulmonary and hepatic damages as well as immune response disorders in pigs that were recognised as especially sensitive to FB Intoxication. The FB1 immunosuppressor induced a higher susceptibility of pigs to gut pathogens such as E coli. Effects on Salmonella have poorly been studied despite the frequent asymptomatic carnage in pigs and the presumptive role of nora equilibrium on prevention of Salmonella excretion or re-excretion. To determine the influence of Salmonella carriage, fumonisins or both on digestive flora equilibrium, the use of a molecular technique CE-SSCP (Capillary-Electrophoresis Single Strand Conformation Polymorphism) appeared a good complement to the conventional bacteriological techniques. The objective was to assess the perturbation of nora associated with co-exposition in experimental conditions in absence of clinical sign

Microscopie de fluorescence résolue à 1µm, rapide et faible coût Application à la sécurité alimentaire

http://www.univ-st-etienne.fr/opt-diag/National audienceProposal of low cost, submicrometer, and fast fluorescence microscopy Microarray scanners are now reaching submicron details for fast scan speeds on large surfaces such as microscope slides. Reading times depend on the required resolution. However, specific applications in food security tend to bring closer to the source the measurements necessary to decision making. For the development of salmonella and listeria on pig carcasses, the measurements taken directly at slaughter need to be interpreted within less than an hour, so that the decision of meat usage in a fresh/cooking circuit does not have significant economic consequence. We developed a method for marking immediately after impacting carcass, which makes it possible to read fluorescence signals 30 minutes after sampling. However, the sampling method leaves the sample some organic residues, whose irregularities in the thickness and the surface can cause problems in reading and interpretation with conventional scanners. We propose a method of packaging and reading for the automatic counting of salmonella with fast scanning, adapted to the environment of the slaughterhouse. Detection is carried out by a 488nm excitation and a conventional 520 nm fluorescence detection using a photomultiplier. The assembly proposed uses optical fibers. It provides a resolution close to 0.5 µm, the diffraction limit at 488nm