The four-component aureocin A70 as a promising agent for food biopreservation

Aureocin A70 is the only four-component bacteriocin described to date. As it inhibits the growth of a wide range of Gram-positive bacteria, including Listeria monocytogenes strains isolated from food, its potential for improving food safety was investigated in this study. Aureocin A70 (10,240 AU/mL) proved to be bactericidal, but not extensively lytic, against listerial strains. The antibacterial activity of aureocin A70 (16 AU/mL) was then tested in UHT treated skimmed milk inoculated with the food-associated L. monocytogenes L12 strain (4-log CFU/mL) during storage at 4 degrees C for one week. Aureocin A70 caused a time-dependent reduction in the listerial viable cell counts (5.51-log units) up to 7 days of incubation. Aureocin A70 was neither toxic to the Vero and the L-929 cell lines nor exhibited a hemolytic activity against sheep red blood cells. Aureocin A70 proved to be completely stable for one month at 25 degrees C, 16 weeks at 4 degrees C and 20 weeks at -20 degrees C. Aureocin A70 exhibited a time-dependent susceptibility to simulated gastric juice and bile salts mimicking gastrointestinal conditions. The entrapment of aureocin A70 in an alginate/gelatin matrix revealed that this bacteriocin can be released from this matrix. Moreover, it remained adsorbed to and active on a low-density polyethylene plastic surface suggesting that aureocin A70 may be employed in bioactive packaging to control the growth of undesirable bacteria. Taken together these results suggest that aureocin A70 is a promising alternative to be used in food applications. (C) 2016 Elsevier B.V. All rights reserved.