عنوان مقاله [English]
Low density polyethylene (LDPE) nanocomposite films incorporating different concentrations of mixed Ag, CuO, and ZnO nanoparticles were produced by melt extrusion. Soy burger produced in a local meat industry packed in the aforementioned films and stored at -18 ºC for 8 weeks. Total count of microorganism and yeast and mold loads of the product was assessed upon every week of storage. Results showed that all nanocomposite films reduced both total count of microorganisms as well as mold and yeast counts. The number of surviving cells of the total count was decreased from 5.77 log to 2 log CFU, whilst mold and yeast load showed a reduction from 4.85 log to 3.07 log CFU. The results show that the film containing 1% ZnO (without Ag-NP and CuO-NP) was the most suitable composition for both microorganism with a desirability more than 0.95. Moreover, microbial models for each composition was suggested using a combined design in Design Expert software. The difference between the optimum points of nanocomposite films and their replication for validation was not significant by SPSS using one-way ANOVA analysis (p<0.05), it was significant pure LDPE, indicating antimicrobial properties of the obtained films. According to Japanese Industrial Standard (JIS Z 2801: 2000) from which ISO 22196 : 2007 derives, an antimicrobial activity of R>2.0 log cfu is required for the nanofood packaging to demonstrate antimicrobial efficacy. Migration assay results for optimum point, ZnO-NP with a food stimulant were well within those allowed by law.