Fresh-cut apples which offer consumers health benefits and convenience have become popular in recent years. There are two major challenges in the processing of fresh-cut apples: development of cut surface browning and possible contamination with human pathogens such as Listeria monocytogenes. The surface browning that impairs sensory properties and discourages consumer purchase of fresh-cut apples is mainly a result of enzymatic reaction of endogenous phenolics with oxygen catalyzed by polyphenol oxidase (PPO). Many antibrowning agents have been developed and evaluated to inhibit PPO activities by using reducing agents (antioxidants), chelating agents, acidulants, etc. However, these compounds have no or little antimicrobial activity against human pathogens and spoilage microorganisms. Indeed, there have been numerous Listeria recalls of fresh-cut apples that had been treated with antibrowning agents in recent years. The source of L. monocytogenes could be preharvest and postharvest, which ultimately lead to the contamination of antibrowning solutions and cut apples. Therefore, chemicals that have both antimicrobial and antibrowning properties have been investigated, such as organic acids, sodium chlorite, and sodium acid sulfate. However, individually the compounds have limited effectiveness in inhibiting browning or reducing populations of L. monocytogenes. Combinations of antimicrobial and antibrowning agents have been investigated. Challenges remain to develop formulations that are natural, safe, economical, and consumer-friendly to meet the shelf-life desired by the fresh-cut apple industry.

Antioxidants and antimicrobials to maintain freshness and minimize Listeria contamination of fresh-cut apples

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.