Poly (lactic acid) and whey protein/pullulan composite bilayer film containing phage A511 as an anti-Listerial packaging for chicken breast at refrigerated temperatures

Listeria phage A511 were stabilized in whey protein concentrate/pullulan (WP) composite and poly (lactic acid) (PLA) bilayer films with different thickness ratios (100%, 70/30%, 50/50%, 30/70%). As the thickness of WP layer decreased, so did the phage recovery from the film. The highest phage recovery belonged to 30PLA/70WP, which was statistically similar to 100WP. Investigation of storage of phage-containing 100WP and 30PLA/70WP films for 60 days at 25 degrees C and 53% relative humidity revealed that films could maintain phage titers for up to 20 days. Phage-containing bilayer film was selected for studying chicken breast due to its better barrier, mechanical, and visual properties than 100WP and stability of these properties during storage. The maximum release of phages from 30PLA/70WP to the chicken breast fillet at 4 degrees C and 10 degrees C occurred after 24 h. The phage-containing films had inhibition effects on Listeria in chicken fillets similar to free phage treatment.

Automated summary

Listeria phage A511 was stabilized in bilayer films of whey protein concentrate/pullulan (WP) composite and poly (lactic acid) (PLA) with different thickness ratios. The recovery of phage decreased as the thickness of WP layer decreased. The 30PLA/70WP film showed the highest phage recovery, similar to the 100WP film. The bilayer film with phage was selected for studying chicken breast due to its better barrier, mechanical, and visual properties. The release of phages from the film to the chicken breast fillet was highest after 24 hours at 4 degrees C and 10 degrees C. The phage-containing films had similar inhibition effects on Listeria in chicken fillets compared to free phage treatment.