Decontamination of Escherichia coli O157:H7 and Staphylococcus aureus from Fresh‐Cut Parsley with Natural Plant Hydrosols

The inhibitory effects of sage, rosemary, oregano and thyme hydrosols were evaluated against Escherichia coli O157:H7 and Staphylococcus aureus inoculated on parsley at high and low concentrations. Following the pathogen inoculations, parsley samples were washed with the hydrosols and sterile tap water as a control for 0, 20, 40 and 60 min, and reductions on pathogen counts were determined. Sterile tap water was ineffective on all conditions tested. After 20 min of application, oregano and thyme hydrosols were able to significantly (P < 0.05) reduce E. coli O157:H7 counts on low inoculum level, while all hydrosols showed significant reductions (P < 0.05) on high inoculum levels at this period. Additional reductions on E. coli O157:H7 counts were observed with the increasing time. S. aureus was more sensitive to hydrosol treatments, and oregano hydrosol was able to completely eliminate S. aureus after 40 min. In conclusion, decontamination of foodborne pathogens from fresh‐cut vegetables can be achieved by hydrosol treatments. PRACTICAL APPLICATIONS: Recent trends in consumer perceptions have led to increased consumption of ready to eat food products and fresh fruits and vegetables. Leafy vegetables such as parsley are one of the most important ingredients of freshly consumed food products including salads. The main concern on leafy vegetables is their high contamination risk with pathogenic microorganisms including Escherichia coli O157:H7 and Staphylococcus aureus and new strategies based on natural preservatives to control these pathogens on leafy vegetables are of particular interest. Plant hydrosols originated from Lamiaceae family which have antimicrobial effects can be important sources of natural preservatives against certain pathogens. Similarly their simple and cheap production method and their safe recognition for human consumption increase their potential usage as natural decontamination agents. In this study the antimicrobial activities of sage, rosemary, oregano and thyme hydrosols against E.coli O157:H7 and S. aureus on parsley samples were evaluated and their efficiencies were determined.