Research note: Mobile slaughter in poultry meat production in Germany - First microbiological results

Small-scale poultry farming is gaining increasing importance in Germany. At the same time, the ongoing structural transformation within the poultry processing sector has led to a growing centralization in a few large-scale slaughterhouses. As a result, many small-scale farms face challenges in having their animals processed. Mobile Poultry Processing Units (MPPUs) offer a promising solution by enabling on-site slaughter of smaller flocks, thereby significantly contributing to animal welfare by eliminating the need for long-distance transportation. However, like stationary facilities, mobile slaughter units must also comply with the stringent hygiene standards required for food processing. In this study, we examined the development of Campylobacter spp., Escherichia coli (E. coli), total aerobic viable counts (TVC) and Salmonella spp. during the slaughter process in a MPPU in western Germany. In total, 160 neck skin samples from broiler and laying hen carcasses as well as surface swab samples, and process water (scalding tank and water bath) were examined. A total of 76 (48 %) carcasses showed Campylobacter counts above the limit of detection (2.3 MPN/g; MPN = most probable number). The distribution of MPN values across processing steps indicated a gradual increase in Campylobacter contamination, with defeathering and evisceration identified as crucial points. Evisceration was associated with the highest intermediate contamination levels, as 26 % of samples (10/39) reaching 23 MPN/g and 18 % of samples (7/40) showing elevated counts of 230 MPN/g. A modest decrease in Campylobacter levels regarding intermediate and elevated counts was observed following the water bath. After scalding, E. coli were not detected, however, after the water bath median counts of 3.67 log CFU/ g were determined. TVC remained relatively stable, ranging between 4.79 log CFU/g (after scalding) and 4.93 log CFU/g after the water bath. Salmonella spp. were not detected. This study provides insights into a mobile poultry processing unit in Germany, highlighting critical hygiene points comparable to those in conventional slaughterhouses. The findings contribute to a better understanding of microbial dynamics in MPPUs and serve as foundation for further investigations.