| Fresh and fresh-cut fruits and vegetables, often eaten with minimum processing, are the potential sources of the food-borne infection. Antimicrobial packaging is one approach for preventing the contamination of pathogens on the surface of a fresh produce. The objective of this study is to develop an edible antimicrobial film coating that can be applied on the surface of fresh produce to prevent growth of pathogens and extend the shelf life. Concentrations of soy (SP), whey (WP), and wheat gluten (WG), protein and carboxymethyl cellulose (CMC) were optimized based on their viscosity. Effect of coating on the color and texture of tomato were evaluated. The effect of partial substitution of glycerol with organic acids on the puncture strength and antimicrobial activity of the soy protein films against Listeria monocytogenes ( L.m.), E. coli O157:H7 (E.c.) and Salmonella gaminara (S.g.) were evaluated. Phenolics, propyl gallate and 2,4-dimethoxy benzoic acid (DMBA), were incorporated into SP film and their antimicrobial activity were evaluated. Soy protein was treated with UV irradiation at different stages of film preparation and the tensile strengths and antimicrobial activity were evaluated.; A novel method was developed to optimize the polymer concentration, based on the viscosity of film-forming solution. The optimum concentrations of SP, WP, WG and CMC to produce films with sufficient mechanical strengths were 10.0, 9.0, 16.5 and 1.75 g/100 g solution, respectively. The optimum concentrations of glycerol in the film were 35, 35, 15 and 15 g/100 g polymer, respectively. Malic acid (2.6%) incorporated soy protein film had the lowest number of survivors of L.m., S.g., and E.c. (5.5, 3.0 and 6.8 log number CFU/ml, respectively). Less than two reductions of log CFU/ml were observed in phenolics incorporated soy protein film. UV treatment to soy protein isolate and the film solution before drying increased tensile strength of the film at pHs 3.0 and 7.0. The antimicrobial activities of the films were not affected by the UV treatment. The edible antimicrobial film developed by incorporating malic acid can be used to prevent the contamination of pathogens on the surface of a fresh produce. |
