Use of bacteriocin-producing starter cultures of Lactobacillus plantarum and Lactobacillus curvatus in production of ostrich meat salami

Ostrich meat salami was produced by using Lactobacillus plantarum strain 423 and Lactobacillus curvatus strain DF126. The strains produce the bacteriocins plantaricin 423 and curvacin DF126, respectively. The specific activity of plantaricin 423 in MRS broth at 30 °C increased as the pH decreased from 6.5 to 3.5, but activity subsequently decreased. The activity of curvacin DF126 increased under the same conditions, but remained stable for the duration of the growth cycle. Maximum curvacin DF126 and plantaricin 423 activity levels were recorded at a culture pH of around 4. The spectra of antimicrobial activity recorded for plantaricin 423 and curvacin DF126 were similar. Neither of the two bacteriocins inhibited the growth of Micrococcus sp. MC50 and did not have any inhibitory effect on either of the producer strains. Curvacin DF126 and plantaricin 423 inhibited the growth of L. monocytogenes in salami meat. However, after 15 h of fermentation the viable count of L. monocytogenes LM1 increased, probably due to a decrease in activity of the bacteriocins and/or the development of resistant bacterial cells. This is the first report on the inhibition of L. monocytogenes in ostrich meat salami by using bacteriocinogenic starter cultures.