Antibacterial properties of LDPE nanocomposite films in packaging of UF cheese

•A microbial model was suggested for antibactierial effect of active LDPE films in UF cheese.•All films had antibacterial effects on colimforms after 4 weeks.•LDPE film with Cu-Zno and with no Ag nanoparticles provided optimum antibacterial effect.•Suggested statistical model verified optimum points obtained in microbial tests.

The purpose of this study was to investigate antibacterial potential of low-density polyethylene (LDPE) packaging films incorporating silver (Ag), copper oxide (CuO) and zinc oxide (ZnO) nanoparticles in measuring of coliform amounts of ultra-filtrated (UF) cheese. The initial LDPE/nanoparticle composites were produced by melting extrusion followed by extruding the obtained composites through a die to achieve a film thickness of 45 ± 5 μm. The number of surviving coliform bacteria was decreased by 4.21 log cfu/g after 4 weeks of storage at 4 ± 0.5 °C, whilst pure LDPE films showed a reduction of only 1.04 log cfu/g. A composition of 0% Ag, 1% CuO, 0% ZnO gave an optimum point in combined design using Design Expert analysis. A suitable microbial model was suggested for retarding coliform bacteria growth in UF cheese. The difference between the optimum point of nanocomposite film and its repeat was not significant (p < 0.05) by one-way ANOVA analysis using SPSS software, while the difference was significant for pure film. Migration of metallic nanoparticles into a food stimulant was within the accepted safe level.