Submitted to: Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/5/2003
Publication Date: 2/1/2004
Citation: Bhagwat, A.A., Saftner, R.A., Abbott, J.A. 2004. Evaluation of wash treatments for survival of foodborne pathogens and maintenance of instrumental and sensory characteristics of fresh-cut apple slices. Food Microbiology. 21(3):319-326. Interpretive Summary: Several fresh-cut produce products are available in supermarkets and in food service facilities, and fresh-cut apples have been introduced as a component in school lunch programs. Preservation of fresh-cut fruits presents unique challenges to the fresh produce industry because these products are prone to microbial contamination. Fresh-cut fruits also have an active metabolism that can result in rapid deterioration of tissue if not controlled. A commercial and three experimental wash treatments for fresh-cut apple slices were evaluated for their ability to affect survival of food-borne pathogens and to maintain quality of the slices. In this study, we demonstrate that the experimental wash treatments showed strong antimicrobial activity against E. coli O157:H7, Salmonella spp. and Vibrio spp. During treatment of apple slices, the wash solutions became progressively adulterated with fruit juice, and they lost their antibacterial activity. Therefore, wash solutions should not be reused on multiple batches of sliced apples. Instead, alternative washing strategies that maintain the antimicrobial properties of wash solutions need to be developed for fresh-cut apple slices. Using wash treatments that both control browning and provide microbial safety will provide new wash solutions for the fresh-cut produce industry and help to safeguard the consumer.
Technical Abstract: A commercial and three experimental wash treatments for fresh-cut apple slices were evaluated for their ability to affect survival of food-borne pathogens and to maintain instrumental and sensory quality characteristics of the slices. 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 became progressively adulterated 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.