Vanillin studied as shelf-life extender
could help prevent fresh cut produce from becoming contaminated
with pathogens, according to new research.
The food industry has been taking reaping the rewards of the increase in consumer demand for convenient and minimally processed produce like fresh-cut apples. However recent outbreaks of food borne diseases from such produce as packaged spinach has made such processors more aware of the need to protect their reputations. Now a study by Vasantha Rupasinghe, a scientist at the Nova Scotia Agricultural College (NSAC), holds out the promise of a new weapon in the arsenal against pathogens. He investigated the antimicrobial effects of vanillin against pathogenic and spoilage organisms in refrigerated fresh-cut apples. Vanillin is the predominant phytochemical that occurs in vanilla beans. It is a flavoring compound used widely in ice cream, beverages, biscuits, chocolate and desserts. Previous research shows that vanillin has antimyotic and bacteriostatic properties, which means it potentially has the ability to destroy or kill fungi and prevent bacteria from multiplying. Rupasinghe said vanillin's properties holds out the possibility of extending the shelf life of certain products could potentially satisfy consumer demand for convenient and nutritious minimally processed foods. He and his team studied the antimicrobial effect of vanillin against E.coli, P. aeruginosa, E. aerogenes, and S. Newport, which are pathogens. They also studied Candida albicans, Lactobacillus casei, Penicillum expasum, and Sacchromyces cerevisie, organisms known for their spoilage properties. These organisms could be generally associated with contaminated fresh-cut produce. The scientists used the "Empire" and "Crispin" cultivars in the study. The apples were harvested at the commercial maturity from a commercial orchard. The vanillin treatment was also combined with an existing fresh-cut processing technology called NatureSeal, a post-cut dip solution that contains calcium ascorbate. NatureSeal is used by processors to prevent enzymatic browning and softening of sliced apples. The research demonstrated that incorporation of vanillin in the post-cut dipping solution of apple slices could inhibit the microbial growth during the 19-day post-cut storage by 37 per cent in the "Empire" apple slices and by 66 per cent in the "Crispin" cultivar. The slices were stored at 4°C. When incorporated with the commercial anti-browning dipping solution NatureSeal, vanillin did not influence the control of enzymatic browning and softening of the anti-browning dipping solution, the study found. "These results provide new insight into the possible use of vanillin as a natural antimicrobial agent in processing of sliced apples and others," said Rupasinghe. Further research is required in order to obtain information about the sensory quality and consumer acceptance of fresh-cut apples treated with vanillin, he said. The research are presented in a paper in Food Research International (39:575-580).