Analysis of nationwide survey data to determine bacterial contamination levels in meat from pig slaughterhouses in Thailand

Bacterial contamination in meat processed in slaughterhouses is a very important public health concern. The present study aimed to compare bacterial contamination levels in meat samples from pig slaughterhouses in six regions of Thailand. A total of 3066 meat samples were collected from pig slaughterhouses (n = 1466) across Thailand in 2019 by the Department of Livestock Development (DLD). All samples were submitted for microbiological analysis to estimate the aerobic plate count (APC) and levels of coliforms, Escherichia coli, Enterococcus spp., Staphylococcus aureus, and Salmonella spp. at DLD laboratories. Across all samples, the average levels of aerobic microorganisms (Lsmean ± SD, 5.01 ± 1.09 log CFU/g), coliforms (2.23 ± 1.21), E. coli (1.54 ± 0.92), Enterococcus spp. (2.05 ± 1.01), and S. aureus (1.48 ± 0.75) were determined. There were differences in bacterial contamination levels in meat samples obtained from different regions. For low- and medium-capacity slaughterhouses, the highest APC and levels of coliforms, E. coli, and S. aureus contamination were observed in meat samples from the eastern and southern regions of Thailand and the highest mean level of Enterococcus spp. contamination was found in meat samples from the eastern regions. The highest percentage of meat samples positive for Salmonella spp. was observed in slaughterhouses in the northern region. For high-capacity slaughterhouses, the highest mean APC and levels of coliforms, E. coli, Enterococcus spp., and S. aureus contamination were observed in meat samples from the southern region. The percentage of samples that were non-compliant with DLD standard criteria differed between regions, ranging from 39.26% to 64.62%. Of all the samples tested, 28.51% were non-compliant for APC, 14.55% for coliforms, 22.34% for E. coli, 18.20% for Enterococcus spp., 8.35% for S. aureus, and 30.10% for Salmonella spp. This study is the first to perform a nationwide documentation of bacterial contamination levels in meat samples from pig slaughterhouses in Thailand. The study findings can be used as supporting information by authorities to improve food safety strategies aimed at decreasing bacterial contamination in pork from slaughterhouses at the national level.