Effect of edible chitosan/clove oil films and high‐pressure processing on the microbiological shelf life of trout fillets

Abstract

BACKGROUND: The inhibitory effect of chitosan filmswith clove oil (0–50 g kg−1)was evaluated on a range of ten representative food spoilage and pathogenic bacteria. RESULTS: Themost sensitive bacteria to the filmswas Shewanella putrefaciens and the most resistantwas Aeromonas hydrophila (inhibitionwas apparent only at 50 g kg−1 clove essential oil (CEO)). Filmswith 20 g kg−1 CEO inhibited nine of ten of the bacteria tested. Chitosan filmswith 20 g kg−1 CEOwere combinedwith high-pressure (HPP) processing as treatments for trout fillets, and changes in physicochemical parameters and microbial load were evaluated at 4 ∘C over 22 days of storage. The films reduced weight loss and water activity compared to fresh and treated samples (HPP and cooking). Results showed that microbial load (total aerobic mesophilic, lactic acid bacteria and total coliform) of the trout fillets covered with chitosan films was lower than that for HPP-treated samples, and similar to cooked samples, except for coliform counts. CONCLUSION: The use of 20 g kg−1 CEO–chitosan films showed a further improvement in the shelf-life of trout fillets when compared to that obtained with HPP and cooking treatment.