Survival and Growth Characteristics of Escherichia coli O157:H7 in Pomegranate-Carrot and Pomegranate-Apple Blend Juices

Abstract

Unpasteurized fruit juice has been implicated in outbreaks of Escherichia coli O157:H7 (E. coli O157:H7). Meanwhile, certain fruit, such as pomegranate, contains antimicrobial components. The objective of this study was to investigate the survival and growth characteristics of E. coli O157:H7 on pomegranate juice in laboratory medium and in pomegranate-carrot and pomegranate-apple blend juices at different concentrations. Single strain of E. coli O157:H7 (E0019, H1730, and Cider) was inoculated into brain heart infusion (BHI) broth or a mixture of three strains was inoculated into the blended juices containing pomegranate juice. Our results showed that the addition of pomegranate juice inhibited the growth of tested E. coli O157:H7 in both laboratory medium and blended juices.The antimicrobial activity increased with increased concentrations of pomegranate juice (P < 0.001) and incubation times.The bacterial population was reduced by at least 2 log CFU/ml in BHI broth and juice blend samples in the presence of 20% and 40% Pomegranate juice respectively. Sensory evaluations performed using a 9 point hedonic scale showed significant satisfaction on using 40% pomegranate juice blend with carrot and apple juices. Our study suggests that pomegranate juice could be used as a natural antimicrobial in different food systems including juices to inhibit the growth of E. coli O157:H7.