Inhibition of Coliform Bacteria in Ultra-Filtrated Cheese Packed in Nanocomposite Films Containing Cloisite30B- Metal Nanoparticles.

Background and Objectives: Antimicrobial active packaging with metallic nanoparticles is used as antimicrobial agent in the packaging of food. This study considers the coliform retarding ability of antimicrobial packaging in ultra-filtrated (UF) cheese. Materials and Methods: Plastic films based on low-density polyethylene containing organoclay (cloisite 30B) and different percentages of Ag and CuO nanoparticles produced by extrusion method. Coliform bacteria growth in UF cheese was investigated. The release of nanoparticles from nanocomposite into a food simulant was also assessed. Results: An amount of 3.17-log cfu/g and 0.75-log cfu/g reduction for coliform bacteria obtained for nanocomposite and control films, respectively after four weeks of storage at 4 °C. Nanocomposite film with 1.3% Ag and 2.7% CuO in LDPE matrix introduced as optimum point by Design Expert 7.1.5 software. Microbial model for decreasing growth of coliform bacteria in this product was also determined. Validation of optimum point was carried out using a one-way ANOVA. It was shown that ther is a non-significant (p>0.05) difference with its repeat and a significant (p<0.05) difference with the pure film. Conclusions: Plastic nanocomposite films containing nanoparticle of organoclay and metal can decrease the severity of food processing and application of chemical preservatives in the food industries. [ABSTRACT FROM AUTHOR]