Genipin cross-linked antimicrobial nanocomposite films and gamma irradiation to prevent the surface growth of bacteria in fresh meats

Abstract

Abstract A 125 μg/mL of nisin and 30 mM of disodium ethylenediaminetetraacetate (EDTA) were immobilized on the surface of the nanocrystal (CNC)/chitosan nanocomposite films by using genipin as a cross-linking agent. The effect of low-dose gamma irradiation on the antimicrobial activity of the films was tested in vitro against Escherichia coli and Listeria monocytogenes. The genipin cross-linked films prepared by irradiating at 1.5 kGy demonstrated the highest antimicrobial activity against both the bacteria at the end of 35 days of storage at 37 °C showing an inhibition zone of 27.1 mm for E. coli and 27.7 mm for L. monocytogenes as compared to 23.4 mm and 23.8 mm for the same respective bacteria at day 1. The films restricted the growth of psychrotrophs, mesophiles and Lactobacillus spp. (LAB) in fresh pork loin meats and increased the microbiological shelf-life of meat sample by more than 5 weeks. The films also reduced the count of E. coli and L. monocytogenes in meat samples by 4.4 and 5.7 log CFU/g, respectively, after 35 days of storage. Industrial relevance Foodborne diseases are responsible for 9.4 million illnesses, 55,961 hospitalization and 1,391 deaths each year in the United States. In the context of a constantly growing population and globalization of markets, and the increase of the demand for ready to eat foods without synthetic additives, the development of new technologies to prevent food contamination and to reduce foodborne illnesses is important. The development of antimicrobial packaging containing natural antimicrobials has been proposed as a novel technology to assure food safety. This technology is gaining interest from researchers and industries due to its potential to prevent the surface growth of pathogenic bacteria in meat products. The limit of the use of natural polymers, in order to reduce the packaging wastes, is their high water permeability and low resistance. The use of nanocellulose can permit to reinforce film and can improve their physico-chemical properties. We have developed a novel biopolymeric matrix reinforced with a nanofiber. The nanofiber is non-toxic, natural and obtainable from renewable sources. Chitosan, is also obtained from renewable sources, non-toxic, biodegradable, has biocompatible properties, and found application in several fields including food packaging.