Microbiological quality of raw berries and their products: A focus on foodborne pathogens

Berry samples (n = 316; strawberries, raspberries, blackberries and blueberries) obtained from a fruit processing plant were examined regarding bacteriological quality and their potential public health risk. Three types of berry products were analysed including raw material, product from the mixing step and final product. Escherichia coli, Salmonella spp., Listeria monocytogenes, Bacillus cereus, sulphite-reducing clostridia spores and coagulase-positive staphylococci were the parameters investigated. Salmonella enterica serovar Braenderup and L. monocytogenes were isolated from one fruit sample of raw material each. Two samples harboured E. coli between 0.7 and 0.9 log cfu g(-1), not exceeding the hygienic criteria. Coagulase-positive staphylococci were not detected in the studied samples; however, coagulase-negative staphylococci (CNS) were isolated from a small proportion of samples mainly raspberries. Presumptive B. cereus were isolated from a relatively large proportion of the samples, raspberries and blackberries being the most contaminated fruits. The absence of pathogenic microorganisms in the final product as well as the low prevalence of presumptive B. cereus and CNS indicates proper implementation of good manufacturing and hygiene practices (GMPs/GHPs) by the food industry. Nevertheless, the results indicate that the raw material examined may contain pathogenic bacteria and thereby represent a risk to consumers regarding the manifestation of foodborne diseases.