Effect of combination of UV-A light and chitosan-gallic acid coating on microbial safety and quality of fresh strawberries. (October 2022)

• Record Type: Journal Article
• Authors: Zhang, Hongchao; Montemayor, Abraham M.; Wimsatt, Stratton T.; Tikekar, Rohan V.
• Is Part Of: Food control. Volume 140(2022)
• Publication Date: 2022-10
• Subjects: UV-A light -- Gallic acid -- Antimicrobial -- Strawberries -- E. coli O157 -- H7 -- Shelf-life; Food -- Quality -- Periodicals; Food -- Analysis -- Periodicals; Food handling -- Periodicals; Food industry and trade -- Quality control -- Periodicals; Aliments -- Industrie et commerce -- Qualité -- Contrôle -- Périodiques; Aliments -- Qualité -- Périodiques; Aliments -- Analyse -- Périodiques; Hygiène alimentaire -- Périodiques; Food -- Analysis; Food handling; Food -- Quality; Periodicals; Electronic journals; 664.07
• DOI: 10.1016/j.foodcont.2022.109106
• Languages: English
• ISSNs: 0956-7135

Abstract

Abstract: Strawberries can be contaminated by foodborne pathogens or mold on farm or during postharvest handling. Photo-irradiation of edible chitosan coating containing gallic acid can be an innovative antimicrobial intervention to improve the safety and shelf-life of strawberries. This study investigated antimicrobial activity of chitosan-gallic acid coating under 360 nm UV-A light. The thin layer of coating material allowed 80% of UV-A light transmission while blocking the majority of UV-C (200–280 nm) light. The formation of the coating layer was visualized by light and confocal microscopes. After 180 min exposure to UV-A, a 2.3 ± 0.4 log reduction of E. coli O157:H7 on chitosan-gallic acid (CH-GA) coated strawberries was achieved, which were significantly (P < 0.05) higher than CH, GA, and CH-GA without UV-A (average 0.3–1.0 log reductions) and UV-A. This level of inactivation was also significantly (P < 0.05) higher than GA + UV-A treatment (1.2 ± 0.4 log reductions), but not significantly different from (P > 0.05) CH + UV-A (1.8 ± 1.0 log reductions) treatment. The photo-irradiated coating did not significantly (P > 0.05) alter the mold decay incidence (%) in strawberries. Additionally, the redness and yellowness values of CH-GA + UV-A treated berries (35.4 ± 0.9, 22.0 ± 1.0) were initially lower (P < 0.05) than the control (40.5 ± 0.3, 26.1 ± 2.6), and became comparable (P > 0.05) after 14 days of storage. Comparatively, their firmness values did not show differences (P > 0.05) throughout the storage. Findings demonstrated the potential for using photo-irradiated coatings to reduce food safety risk in strawberries. Highlights: Chitosan-gallic acid coating (CH-GA) on strawberries formed uniform and thin layers. CH-GA + UV-A showed improved antimicrobial ability than individual treatments. GA did not enhance the action of CH + UV-A against E. coli on strawberries. CH-GA + UV-A had limited adverse quality impacts on the fresh strawberries.