Microbial contamination of pig carcasses at a slaughterhouse in vientiane capital, LAO PDR

Abstract

A cross-sectional study was conducted to determine microbial contamination of pig carcasses at a slaughterhouse in Vientiane, capital of Lao People Democratic Republic (Lao PDR). Between November 2004 and April 2005, 62 pig carcasses were randomly selected. From each carcass, pooled swabs (from "1" prior to and "2" after evisceration) and 25 g of tissue of mesenteric lymph nodes (MLN) were collected. The swab samples were examined for Aerobic Plate Count (APC) and Enterobacteriaceae Counts (EBC) and cultured for Salmonella. The lymph nodes were cultured for Salmonella only. Swabs 1 and 2 had mean APC of 4.70 and 4.85 log 10CFU/cm 2, respectively. These two means were significantly (p=0.0001) different. The means of EBC were 2.81 log 10CFU/cm 2 for Swab 1, and 2.98 log 10CFU/cm 2 for Swab 2. The difference were also statistical significant (p=0.0001). The frequency of Salmonella isolation from Swab 1 was 46.8%, for Swab 2 was 66.1 %, and from mesenteric lymphnodes was 53.2%. Eight different Salmonella serotypes were identified. The most frequent (29.1%) serotype was S. Rissen, followed by S. Anatum (26.2%), S. Derby (18.4%), and S. Elisabethville (8.7%). The other serotypes identified were S. Amsterdam (7.8%), S. Typhimurium (4.9%), S. Agona (2.9%), and S. Enteritidis (1.9%). Results of this study showed the levels of contamination with aerobic bacteria and Enterobacteriaceae were higher than recommended standards, and the carcasses were contaminated with Salmonella.