Bacteriocins and culture products

Bacteriocins with potential for use in foods are produced by strains of Carnobacterium, Lactobacillus, Lactococcus, Leuconostoc, Pediococcus, and Propionibacterium (Montville et al., 2001; Chikindas and Montville, 2002). Many of these compounds could potentially be used as food antimicrobials but, at the present time, few are approved by regulatory agencies to be added to foods in their purified form. One approach to using these compounds has been to grow bacteriocin-producing starter cultures in a medium such as whey, non-fat dry milk or dextrose. The fermentation medium is then pasteurized and spray-dried which kills the starter culture but retains the active antimicrobial. These products act as antimicrobial additives but are generally considered toxicologically acceptable and, depending upon the country, may be listed as 'cultured whey' or 'cultured non-fat dry milk' on the food label. Examples of such products are Microgard®, AltaTM, and PerlacTM AltaTM at 0.1-1.0% was shown to decrease the growth rate of Listeria monocytogenes on vacuum-packaged smoked salmon stored at 4 or 10°C (Szabo and Cahill, 1999). Degnan et al. (1994) inoculated fresh blue crab (Callinectes sapidus) with a 3 strain mixture of L. monocytogenes (ca. 5.5 log CFU/g) and washed with various fermentation products (2,000-20,000 arbitrary units [AU]/ml of wash) and stored at 40C. Counts of Listeria monocytogenes decreased 0.5-1.0 log with Perlac or MicroGard and 1.5-2.7 logs with Alta.

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