Improvement of the microbiological quality of Argentinian Port Salut cheese by applying starch-based films and coatings reinforced with rice bran and containing natural antimicrobials

Abstract

In order to improve the microbiological stability of Argentinian Port Salut cheese stored at 12°C, starch-based edible films and coatings reinforced with rice bran and added with natamycin and nisin (NANI) were evaluated against a surface contamination of Saccharomyces cerevisiae and Listeria innocua (mixed culture). Films with or without antimicrobials and a commercial film prevented the microorganism passage on cheese. However, only films containing NANI (0.0068 g and 0.027 g /100 g slurry, respectively) and coatings formulated with natamycin (0.0204 g /100 g slurry) and nisin (0.081g /100 g slurry) properly reduced the inoculated spoilage on coverings. Besides, NANI films allowed the antimicrobial diffusion to the cheese surface. For all mentioned NANI systems, yeast population was below 2 log (CFU/mL) after 48 hr and bacterial count was at least 2 log cycles lower than other films along the storage. These results show that coverings supporting NANI effectively reduced the microbiological contamination offering a safer product. Practical applications: Our research demonstrates that edible films and coatings reinforced with rice bran and containing nisin and natamycin are an effective method to control the post-process and external contamination of Argentinian Port Salut cheese. These matrices successfully can contribute to improving the cheese microbial stability, offering to the consumer a safer food product. The developed films and coatings can be incorporated to the end of the manufacturing process, thus contributing to better cheese preservation during storage by applying an environmentally friendly treatment.