Antibacterial LDPE films for food packaging application filled with metal-fumed silica dual-side fillers

There is a paramount demand on the enhancement of plastic package properties to reduce food loss and waste. With this awareness, ternary composite films based on low density polyethylene (LDPE) reinforced with silver- (Ag/FS), copper- (Cu/FS) and copper hydroxynitrate-fumed silica (CuHS/FS) micron-sized dual-side fillers, were produced via melt-blending and compression molding techniques. The ternary films exhibited antibacterial activity against the foodborne pathogens Staphylococcus aureus and Salmonella enterica, showing a stronger effect in the LDPE-Cu/FS with a 0.3% and 30.9% survival ratio, followed by LDPE-CuHS/FS films with a 0.4% and 50.7%, respectively. The specific Cu migration presented a maximum value of 1.29 mg/ kg of food simulant, that is within the threshold limit established by current legislation for food contact materials, thus permitting their use as packaging films for acidic, alcoholic, and aqueous foodstuffs. This work presents the relevance of alternative fillers to produce active packaging products.The authors want to acknowledge Maria Eugenia Sotomayor for the "known-how" regarding the melt-blending process, and the EMSUR (Spain) company for the support in the investigation and as the polymer provider. Diogo Videira-Quintela thanks the University of Alcalá for his Ph.D. scholarship (FPI-UAH). This work was supported by the University of Alcalá [Grant No. CCG2018/EXP-039]; and the Ministry of Science and Innovation of Spain [Grant No. MAT2014-57557-R]