Enhanced control of Listeria monocytogenes by in situ-produced pediocin during dry fermented sausage production

Abstract

To determine whether pediocin is produced and has effective antilisterial activity during food fermentation, six sausage fermentation trials were conducted with antibiotic-resistant, pediocin-producing (Bac+) Pediococcus acidilactici PAC 1.0 (Strr Rifr) and an isogenic pediocin-negative (Bac-) derivative used as a control. Meat was inoculated (ca. 10(5) CFU/g) with a composite of five Listeria monocytogenes strains, each electrotransformed with pGK12 (Cmr Emr). P. acidilactici and L. monocytogenes populations were selectively enumerated by plating on media with antibiotics. This study indicated that the dry sausage fermentation process can reduce L. monocytogenes populations. Effective inactivation of L. monocytogenes was observed when the pH at the end of the fermentation portion of the process was less than 4.9. Pediocin was responsible for part of the antilisterial activity during the fermentation in each of the six trials. Furthermore, inhibition of L. monocytogenes during drying was enhanced in the presence of pediocin in the three trials in which L. monocytogenes could be detected throughout the drying process. Thus, pediocin production contributed to an increase in safety during both the fermentation and drying portions of sausage manufacturing.