P3-159 Quantitative Microbial Risk Assessment of Clostridium perfringens in Natural and Processed Cheeses

Wednesday, August 6, 2014
Exhibit Hall D (Indiana Convention Center)
Heeyoung Lee, Sookmyung Women's University, Seoul, South Korea
Kyungmi Kim, Sookmyung Women's University, Seoul, South Korea
Kun Sang Park, Korea Food and Drug Administration, Chungcheongbuk-do, South Korea
Soon Han Kim, Ministry of Food and Drug Safety, Chungcheongbuk-do, South Korea
Junil Jo, Ministry of Food and Drug Safety, Chungcheongbuk-do, South Korea
Young Jo Kim, Ministry of Food and Drug Safety, Chungcheongbuk-do, South Korea
Yohan Yoon, Sookmyung Women’s University, Seoul, South Korea
Introduction: Clostridium perfringens spores generally exist in natural environment rather than vegetative cells. If C. perfringens spores exist in milk, the spores may not be destroyed by pasteurization, and thus, the spores may be still alive even in cheese.

Purpose: The purpose of this study was to evaluate the risk of C. perfringens foodborne illness for natural and processed cheeses.

Methods: To evaluate the risk of C. perfringens foodborne illness for natural and processed cheeses, the hazard of C. perfringens was identified through literatures, and dose response models were also searched to characterize the hazard of the pathogen. For exposure assessment, prevalence of the pathogen, storage temperatures, storage time, and annual amounts consumption were surveyed. Subsequently, a simulation model was developed using the collected data, and the simulation result was used to estimate the probability of illness with @RISK.

Results: C. perfringens was determined to be low risk group on cheese by hazard identification, and the exponential model (r=1.82×10-11) was appropriate for hazard characterization. Annual consumption amounts of natural and processed cheeses were 11.69±11.22 g and 19.43±15.38 g, respectively. The contamination level of C. perfringens on cheeses was below detection limit (< 0.30-0.45 log CFU/g), and initial contamination level was estimated by beta distribution (α1=1, α2=91) to be -2.35 log CFU/g. Moreover, there was no growth of C. perfringens spores during distribution and storage. These data were used for risk characterization by a simulation model, and the mean and maximum values of the probability of C. perfringens foodborne illness per person a day on natural and processed cheeses were 9.57×10-14 and 3.58×10-14, respectively.

Significance: These results can be used to establish a microbial regulation for C. perfringens on natural and processed cheeses.