Effectiveness of Bacteriophages Against Biofilm-Forming Shiga-Toxigenic on Leafy Greens and Cucumbers.

Shiga-toxigenic (STEC) have caused several produce-associated outbreaks, making it challenging to control these pathogens. Bacteriophages could serve as effective biocontrol. Spinach, lettuce, and cucumbers, inoculated with STEC (O157, O26, O45, O103, O111, O121, O145), were treated with lytic bacteriophages and stored at 4°C for 3 days. Surviving STEC were enumerated and observed under scanning electron microscope (SEM), and data analyzed using one-way analysis of variance (ANOVA) ( < 0.05). Bacteriophage treatments significantly reduced STEC populations, compared with the control ( < 0.05). On spinach and romaine, STEC O26, O45, and O103 were reduced to undetectable levels and STEC O157, O111, O121, and O145 by ∼2 logs CFU/cm. Multiserotype phage cocktail reduced STEC on leafy greens by 1.4 CFU/cm and on cucumbers by 1.7 logs CFU/cucumber. Clusters of STEC cells, surrounded by extracellular matrix, were observed under SEM of positive control, whereas phage-treated produce surface showed fewer cells, with cellular damage. Bacteriophages could be utilized as biocontrol against STEC on fresh produce.