Incorporation of nisin into a meat binding system to inhibit bacteria on beef surfaces

In two separate experiments, the bacteriocin, nisin, was incorporated into a commercially available meat binding system (Fibrimex) and applied to meat surfaces as a way of inhibiting the meat spoilage organism, Brochothrix thermosphacta during extended refrigerated storage. In experiment 1, pre-rigor lean beef carcass tissue (BCT) was inoculated with B. thermosphacta, left untreated (U), treated with 10 micrograms ml-1 nisin (N), Fibrimex (F) or Fibrimex containing 10 micrograms ml-1 nisin (FN), held aerobically at 4 degrees C for up to 7 d, and populations of B. thermosphacta and nisin activity determined. Experiment 2 determined the effects of the same treatments but on post-rigor, frozen and thawed lean BCT that was inoculated, vacuum-packaged, and stored at 4 degrees C for up to 14 d. In both experiments, N- and FN-treated tissues exhibited significantly lower populations of B. thermosphacta compared to U- and F-treated tissues, for the duration of refrigerated storage. Nisin activity was detected up to 7 d in N- and FN-treated samples from experiment 1. However, activity was detected only to days 0 and 2 in FN- and N-treated samples, respectively, from experiment 2. These studies indicate that the addition of a bacteriocin to a meat binding system and application to meat surfaces may be useful in reducing undesirable bacteria in restructured meat products.