Evaluation of polyamide composite casings with silver–zinc crystals for sausages packaging

This study assessed the manufacture of polyamide (PA-6) composite casings based on silver–zinc crystals with potential application in sausages packaging. The antimicrobial activity of silver–zinc crystals was estimated by the minimum inhibitory concentration method for microbial strains related with the spoilage of meat products. PA-6 films were prepared as a multilayer film by bubble film sheet co-extrusion (130 °C–14,000 kPa), identified according to the layers distribution as control and active casings by adding 3% (w/w) of silver–zinc crystals to obtain a film with good barrier and mechanical properties. DSC, DMTA and SEM were also evaluated for determining the effects of microparticles in the polymeric matrix. Silver–zinc crystals inhibited the growth of various microbial strains, being Salmonella typhimurium ATCC 14028 which presented greatest resistance. Silver–zinc crystals were well impregnated in PA-6 films. Inclusion of silver–zinc crystals did not modify the mechanical properties and decreased the oxygen transmission rate of the films.