P1-159 Risk of Infection with Salmonella and Listeria monocytogenes Due to Consumption of Ready-to-Eat Leafy Vegetables in Sao Paulo, Brazil

Monday, July 23, 2012
Exhibit Hall (Rhode Island Convention Center)
Anderson Sant'Ana, University of Sao Paulo, Sao Paulo, Brazil
Bernadette D.G.M. Franco, University of Sao Paulo, Sao Paulo, Brazil
Donald Schaffner, Rutgers University, New Brunswick, NJ
Introduction: Although many quantitative microbiological risk assessment (QMRA) models have been developed in the last 15 years, few QMRA models for fresh ready-to-eat produce are currently available. The development of QMRA models focusing on fresh produce is very important because of increasing concern over fresh produce safety.

Purpose: The current study was carried out to estimate the risks of infection due to consumption of RTE vegetables contaminated with Salmonella and Listeria monocytogenesin Sao Paulo, Brazil.

Methods: The risk assessment model was composed of five different modules comprising the retail to consumption steps. A total of 8 scenarios were simulated using pathogen prevalence and concentration levels reported in RTE vegetables in Brazil as well as scenarios where lower prevalence and concentration were assumed. Scenarios where temperature during transportation and storage were maintained below 7°C were also evaluated. Models built in Excel spreadsheets were run (100,000 iterations) using @Risk software. The outputs obtained were risk of illness per month and predicted number of cases of illness in Sao Paulo, Brazil.

Results: The reduction of prevalence of Salmonella from 1.7% to 0.7% resulted in a decrease of risk of illness per month of up to 7 times. The reduction of prevalence of L. monocytogenes from 2.2% to 0.22% resulted in decrease of risk of infection from 1.87E-08 to 2.90E-09. The risks and number of cases predicted in scenarios in which temperature was kept below 7°C were significantly reduced for both pathogens when compared to scenarios using temperature data from the literature. The scenarios where prevalence and concentration of pathogens were reduced, and where temperature < 7°C led to the lowest number of cases of infection due by Salmonella and L. monocytogenes(185 and 3.81E-05 cases per month in Sao Paulo, respectively).

Significance: The results suggest that mitigation strategies that reduce pathogen prevalence and concentration as well as improved temperature control should reduce microbial risk from fresh produce in Sao Paulo, Brazil.  More data are needed to improve the accuracy of risk assessment models developed.