Research Note: Gut instincts: Salmonella contamination based on monitoring systems in the broiler sector

Salmonellosis is the second most important zoonosis in Europe, with consumption of contaminated broiler meat and its derivative products as an important source of infection. One of the many measures to prevent Salmonella contamination of poultry meat at the slaughterhouses is logistic slaughter, this means that per day the contaminated flocks are slaughtered after the Salmonella free flocks. However, this principle relies on a monitoring system at farm level that is prone to false negatives. Therefore, this study evaluated the Salmonella status determined at farm level three weeks before slaughter using minimum 2 pairs of overshoes by comparing it with the Salmonella status at slaughter determined by testing the duodena and ceca contents of 153 flocks. Per flock, 30 gastro-intestinal packages were analyzed. This showed that despite the negative Salmonella status of all flocks, based on the overshoe samples, 20.9 % tested positive when analyzing intestinal samples at slaughter. The most abundant serovar was Infantis (68.8 %), followed by Paratyphi B var. Java (25.0 %). Other notable observations were that no differences in Salmonella prevalence were found between the different slaughter ages of 5 and 6 weeks (P = 0.431) and that Salmonella was more frequently isolated from the duodena than from the ceca (90.6 % and 53.1 % respectively; P = 0.001). In conclusion, more in-depth research is needed to understand the different reasons for the discrepancies in monitoring results, resulting in a re-evaluation of the current monitoring system to guarantee more correct logistic slaughter.