Evaluation of wash treatments for survival of foodborne pathogens and maintenance of quality characteristics of fresh-cut apple slices

A commercial and three experimental wash treatments for fresh-cut apple slices were evaluated for their ability to affect survival of foodborne pathogens and to maintain quality characteristics measured instrumentally and by sensory analysis. For each apple variety (Fuji and Granny Smith), instrumental firmness, cut surface color, and sensory scores for firmness and flavor of fresh-cut apple slices treated with the commercial and experimental wash solutions were similarly maintained during storage (6 days at 5°C). Prior to their use with apple slices, all three experimental wash solutions reduced the survival of Salmonella serovar Typhimurium and Vibrio cholera by 5 logs or more and the experimental solution at pH 2.0 also reduced survival of Escherichia coli O157:H7, Listeria monocytogenes and Shigella flexneri by at least 5 logs, whereas the commercial wash solution had antibacterial activity only against V. cholera. During treatment of apple slices, the wash solutions changed compositionally over time as indicated by a decrease in conductivity, increases in soluble solids content and osmolality, and changes in pH; and they lost their antibacterial activity. Keeping microbial safety in view, wash solutions should not be reused on multiple batches of sliced apples. Instead, alternative washing strategies that maintain the antimicrobial properties of the wash solutions need to be developed for fresh-cut apple slices.