The inhibitory effect of traditional pomegranate molasses on S. typhimurium growth on parsley leaves and in mixed salad vegetables

Pomegranate (PG) molasses is an essential condiment that is commonly used in Middle Eastern cuisine in local and international gastronomic markets. There is scarce information on the inhibitory effect of PG molasses on Salmonella growth mainly under in situ conditions and in a food matrix. PG molasses in different dilution ratios of 1:1 and 1:7, combined with sodium chloride (2%, v/v), vinegar (2.4%, v/v), and in a dressing mix was tested against Salmonella enterica serovar Typhimurium LT2 on parsley and salad vegetables. The results showed significant log reductions in Salmonella on parsley treated with PG solutions for 15, 30, and 60 min, reaching a level of 2.55 log cfu/g. The addition of sodium chloride (2%, v/v) and vinegar (2.4%, v/v) to PG molasses did not exert a synergistic or antagonistic effect on its antibacterial activity. Additionally, the application of PG molasses dressing on salads contaminated with low (3 log cfu/g) and high (6 log cfu/g) inoculum levels resulted in 2–3 log reduction independent of temperature (p <.05) compared with 0.5–1 log reduction for thorough washing alone which may damage the leaf surfaces. This study showed that PG molasses has a great efficacy against S. typhimurium and the potential to enhance the microbial safety of ready-to-eat salads and parsley leaves. Practical applications: The implication of fresh-cut vegetables in food poisoning are well documented, at the same time, the washing methods in restaurants or home settings are reportedly not effective enough to mitigate the risks of pathogens found in vegetables. This study shows that Pomegranate (PG) molasses has a greater efficacy than chlorine (200 ppm) against S. typhimurium and achieved comparable to greater log reduction values than organic acids. The storage temperature and food matrix did not alter the potency of PG. The present work showed that promoting the use of PG as a natural additive and condiment to ready-to-eat (RTE) vegetables offers a great potential to effectively reduce the risk of Salmonella contamination and to improve their microbial safety. Furthermore, this study provided preliminary data that serve as additional inputs in quantitative microbial risk assessment models for estimating the risk of Salmonella infection associated with consuming RTE salads served in Mediterranean cuisines. © 2018 Wiley Periodicals, Inc.