Characterization of antimicrobial properties of Salmonella phage Felix O1 and Listeria phage A511 embedded in xanthan coatings on Poly(lactic acid) films.

Beyond simply providing a barrier between food and external contaminants, active packaging technologies aim to inhibit pathogen survival and growth within the packaged environment. Bacteriophages have a proven track record as targeted antimicrobials but have yet to be successfully integrated in active packaging without serious loss of activity. We have developed two bacteriophage based xanthan coatings on poly(lactic acid) (PLA) film which significantly inhibits Salmonella Typhimurium and Listeria monocytogenes growth in culture (P < 0.01), and significantly reduces survival and growth of diverse cocktails of Salmonella sp. and L. monocytogenes respectively on precooked sliced turkey breast over 30 days of anaerobic packaging at 4 or 10 °C (P < 0.05). Specifically reductions of 0.832 log at 4 °C and 1.30 log at 10 °C for Salmonella sp., and 6.31 log at 4 °C and 1.52 log at 10 °C for L. monocytogenes were observed. The coating containing Listeria phage A511 also significantly inhibited growth of L. monocytogenes over 14 days in aerobic packaging (3.79 log at 4 °C, 2.17 log at 10 °C, P < 0.05). These coatings showed 99.99% phage release within 30 min for both phages. Similar approaches could be used to develop packaging inhibitory to other significant foodborne pathogens such as Campylobacter, and Escherichia coli, as well as spoilage bacteria.