The antimicrobial effects of three phenolic extracts from Rosmarinus officinalis L., Vitis vinifera L. and Polygonum cuspidatum L. on food pathogens

In this study three phenolic extracts were examined, without volatile fraction, against common food pathogens. The samples, all suitable for food application, were from the leaves of Rosmarinus officinalis L., Vitis vinifera L., and the root of Polygonum cuspidatum L. The microorganisms tested were Escherichia coli O157:H7, Salmonella Enteritidis, Salmonella Typhi, Yersinia enterocolitica and Listeria monocytogenes, well-known as important food pathogens. The results demonstrated a microbicidal activity of all the tested compounds at different concentrations; the rosemary extract showed greater efficacy than the other compounds against the tested microorganisms. In particular, the best results were obtained with rosemary extract against E. coli O157:H7 and L. monocytogenes with values of 200 and 270 μg/mL, respectively. Our results show that rosemary extract, often present as a natural antioxidant in food, can also be proposed as a natural disinfectant in the food field.