Purpose: This study aims to compare the efficacy of various sanitizers and hot water treatment in eliminating Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., and natural microflora on mung bean sprouts.
Methods: Un-inoculated or inoculated sprouts were treated with acidic electrolyzed water (AEW) (75 ppm available free chlorine, ORP 1,150 mV, pH 2.8, 180 s), acidified sodium chlorite (ASC) (1200 ppm, pH 2.3, 180 s), cetylpyridinium chloride (CPC) (2%, 180 s), ozonated water (2 ppm, 180 s), trisodium phosphate (TSP) (10%, pH 12.6, 180 s) and hot water (70°C, 20 s) at room temperature. Mean values of bacterial counts were compared using ANOVA.
Results: The hot water treatment reduced by 4.2-, 4.4-, 4.8- and 4.4-log in the population of E. coli O157:H7, L. monocytogenes, Salmonella spp. and natural microflora on mung bean sprouts, respectively. On the other hand, AEW, ASC, CPC, ozonated water and TSP resulted in less than 2-log reduction in the same bacterial strains. However, hot water treatment also caused detrimental impact on the color and firmness of the bean sprouts after treatment or during storage for 4 days at 4 and 25°C. Nevertheless, the present results indicate that hot water treatment could have a high potential for postharvest control measure to improve the microbiological safety of raw mung bean sprouts compared to the chemical sanitizers. Thus, this study suggests that the method needs to be further modified to better retain the physical quality of raw mung bean sprouts.
Significance: These findings may help to expand the limited pool of information on the efficacy and feasibility of decontamination treatments on sprouts.