Lucas Wijnands
National Institute for Public Health and the Environment,Netherlands
Title: Prevalence, concentration and the related microbiological risk of bacterial pathogens in raw produce and minimally processed packaged salads produced in and for the Netherlands
Biography
Biography: Lucas Wijnands
Abstract
Outbreaks with vegetable or fruits as vehicles have raised interest in the characterization of the public health risk due to microbial
contamination of these commodities. Because such data are lacking, we conducted a survey to estimate the prevalence and
contamination level of raw produce and the resulting minimally processed packaged salads as sold in Th e Netherlands. A dedicated
sampling plan accounted for the amount of processed produce in relation to the amount of products, laboratory capacity, and seasonal
infl uences. Over 1,800 samples of produce and over 1,900 samples of ready-to-eat mixed salads were investigated for Salmonella
enterica serovars, Campylobacter spp., Escherichia coli O157, and Listeria monocytogenes. Th e overall prevalence in raw produce
varied between 0.11% for E. coli O157 and L. monocytogenes and 0.38% for Salmonella. Chain logistics, production fi gures, prevalence
data, and consumption patterns were combined with the survey data for the risk assessment chain approach. Th e results of the
sample analysis were used to track events from contamination through human illness. Wide 95% confi dence intervals around the
mean were found for estimated annual numbers of illnesses resulting from the consumption of mixed salads contaminated with
Salmonella Typhimurium DT104 (0 to 10,300 cases), Campylobacter spp. (0 to 92,000 cases), or E. coli (0 to 800 cases). Th e main
sources of uncertainty are the lack of decontamination data (i.e., produce washing during processing) and an appropriate doseresponse
relationship. For the latter, investigations for Salmonella and Shiga Toxin producing E. coli are set in motion.