Quantitative risk assessment model for salmonellosis in chicken skewers from street food vendors in South Korea

Abstract

The objectives of this study were to conduct a quantitative microbial risk assessment (QMRA) for Salmonella in chicken skewers sold by street food vendors in South Korea and to explore the association of microbial growth with thermal inactivation of microbes during the preparation of chicken skewers. Data on raw broiler chicken meat and chicken skewer preparation, as well as typical ambient temperatures in Seoul, were collected and described using probability distributions. The QMRA was performed using an Excel spreadsheet and was created using @Risk. The wholesale-to-consumption process was modeled as a series of unit operations and associated pathogen events that initiate contamination at the wholesale stage, bacterial growth during transport and holding, thermal inactivation during preheating and reheating, and dose response after consumption. The QMRA simulations predicted that extended holding time would affect the likelihood of illness more in warmer months than in cooler months. In addition, when the heating period of food was split and the total heating period was constant, the simulation predicted the preheating phase to be longer than the reheating phase for effective thermal inactivation of Salmonella. Our results suggest that holding the chicken skewers at ambient temperature between split heating events is less effective than continuous heating for thermal inactivation of microbes. In addition, holding makes foods more vulnerable to microbes, particularly when the holding time is long, ambient temperature is high, and preheating time is relatively short compared with reheating time. HIGHLIGHTS • Extended holding time increases likelihood of illness in warmer than it does in cooler months. • Split heating is less effective than continuous heating for inactivation of microbes. • Longer holding times make meat more vulnerable to microbes.