Phenotypic Prediction: Linking Virulence to the Genomics of 59 Strains.

The increased availability of whole-genome-sequencing techniques generates a wealth of DNA data on numerous organisms, including foodborne pathogens such as . However, how these data can be used to improve microbial risk assessment and understanding of epidemiology remains a challenge. The aim of this study was to assess variability in virulence and genetic characteristics between and within different serovars.

Quantification of Survival and Infection in an Model of the Human Intestinal Tract as Proxy for Foodborne Pathogens.

Different techniques are available for assessing differences in virulence of bacterial foodborne pathogens. The use of animal models or human volunteers is not expedient for various reasons; the use of epidemiological data is often hampered by lack of crucial data. In this paper, we describe a static, sequential gastrointestinal tract (GIT) model system in which foodborne pathogens are exposed to simulated gastric and intestinal contents of the human digestive tract, including the interaction of pathogens with the intestinal epithelium.

Prevalence and concentration of bacterial pathogens in raw produce and minimally processed packaged salads produced in and for the Netherlands.

Recent 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 qualitative and quantitative data regarding prevalence and concentration of various microbes 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 The Netherlands. A dedicated sampling plan accounted for the amount of processed produce in relation to the amount of products, laboratory capacity, and seasonal influences.

Influence of Reconstitution on Isolation and Enumeration of Listeria monocytogenes from Milk Powder Used for Reference Samples.

To test the performance of the Listeria isolation methods, reference samples consisting of gelatin capsules filled with spray-dried milk powder containing Listeria have been developed. During the spray-drying process the Listeria cells are exposed to heat stress and are susceptible to osmotic stress during the reconstitution procedure. To limit the effect of osmotic shock, the milk powder has to be encapsulated in gelatin in order to guarantee slow dissolution.