QUANTITATIVE MICROBIAL RISK ASSESSMENT OF STREPTOCOCCUS SUIS SEROTYPE 2 FROM PORK CONSUMPTION

Abstract

This study aimed at determine prevalence and concentration of Streptococcus suis contamination in pork production chains as well as evaluate the health risk attributable to S. suis serotype 2 from pork consumption in Thailand. In total, 492 pig-to-pork and 480 environmental samples were collected from 4 pork production chains in Bangkok. Besides, total 1,036 pork samples were also collected from traditional and modern trades in Chiangmai, Phayao, Nan, Khonkaen, Mukdahan, Saraburi, Nakhonpathom, and Phang-nga provinces. All samples were enumerated using plate count method. S. suis isolates were confirmed by detecting cps2-j gene, followed by Quellung reaction. A stochastic risk assessment model was constructed using the available information together with the results from this study. Total 11.4% (56/492) of pig-to-pork samples and 5.2% (25/480) of environmental samples from Bangkok were positive to S. suis. Total 1% (10/1,036) of pork samples from both traditional and modern trades were positive to S. suis, with an average concentration of 4.22 log cfu/g. There was no S. suis serotype 2 detected from all pork samples. The estimated daily risk of S. suis serotype 2 illness from pork consumption was 1.3 x 10-7 or equilvalent to 4.6 cases per 100,000 persons, annually. A sensitivity analysis revealed that exposure dose, bacterial concentration at consumption and storage time at home greatly impacted the risk estimate.