Development of bioactive food packaging materials using immobilised bacteriocins Lacticin 3147 and Nisaplin®

Immobilisation of the bacteriocins nisin and lacticin 3147 to packaging materials was investigated. Stability of both cellulose-based bioactive inserts and anti-microbial polyethylene/polyamide pouches was examined over time. Antimicrobial activity against the indicator strain Lactococcus lactis subsp. lactis HP, in addition to Listeria innocua DPC 1770 and Staphylococcus aureus MMPR3 was observed for all bacteriocin-adsorbed materials. Activity retention of the inserts showed an initial decrease in the first week of storage but remained stable for the remaining 3 months of the trial. However, adsorption of lacticin 3147 to plastic film was unsuccessful, nisin bound well and the resulting film maintained its activity for 3-month period, both at room temperature and under refrigeration. When applied to food systems, the anti-microbial packaging reduced the population of lactic acid bacteria in sliced cheese and ham stored in modified atmosphere packaging (MAP) at refrigeration temperatures, thus extending the shelf life. Nisin-adsorbed bioactive inserts reduced levels of Listeria innocua by greater than or equal to 2 log units in both products, and Staphylococcus aureus by similar to 1.5 log units in cheese, and similar to 2.8 log units in ham. Similar reductions were observed in cheese vacuum-packaged in nisin-adsorbed pouches. (C) 2000 Elsevier Science BN. All rights reserved.