Effect of reusing heat-treated scalding water on carcass hygiene in industrial pig slaughterhouse

Abstract

To save water resources, scalding water used in a pig slaughterhouse was treated at 80 °C for 3 h and reused the next slaughtering day. Water samples were collected before and after the treatment and at the end of the slaughtering day to evaluate the microbial counts. Aerobic colony counts were not significantly different in water samples between treated and clean water at the beginning of the slaughtering day (2.59 and 2.61 log CFU/mL; p = 0.93), and no Enterobacteriaceae and Salmonella spp. were ever detected in the water. Furthermore, the microbial counts of pig carcass after water treatment, sampled immediately after scalding, was compared with those obtained by replacing it with clean water. The aerobic colony count was 5.60 and 5.83 log CFU/400 cm2 at the start of the slaughtering day and 5.72 and 5.49 log CFU/400 cm2 at the end of the slaughtering day, in control and reused water respectively. Higher aerobic colony counts were detected at the beginning of the slaughtering days in treated groups and at the end of the slaughtering days in control groups. Salmonella was detected in a few carcasses, independently for treated and control groups, and no relation with water treatment could be found.