Packaging based on Ag-Low Density Polyethylene for shelf-life extension of pasteurized and traditional butters at refrigerated temperature

This article focuses on increasing the shelf life of both pasteurized (Pa) and traditional (Tr) butters wrapped in Ag-Low Density Polyethylene (LDPE) film in concentration of 2.5%, 7.5%, 12.5%, and 17.5% at refrigerated temperature up to one month. Silver nanoparticles were synthesized (20.63 nm) through the chemical reduction followed by the melt mixing method to produce AgLDPE films. A mixed model-ANOVA Repeated Measurement presented that total bacteria, S. aureus and E. coli were eliminated from the Pasteurized butter samples wrapped with 17.5% Ag/LDPE films. In comparison, psychrophilic bacteria can be eradicated by 2.5-17.5% Ag/LDPE films after 30d. Peroxide value showed a slight fall from 0.50 and 0.28 meq/kg, respectively for Pa and Tr butters on the 1st day in the control group to 0.31 and 0.24 meq/kg, respectively in the butter wrapped with 17.5% Ag-LDPE film at the end of the storage with no significant difference (p > 0.05) with other treatments. Iodine value was decreased after 30d. It is concluded that the use of 17.5% Ag/LDPE as a coating of butter can safely preserve pasteurized butter at least a month.