Attività antimicrobica di Bacillus subtilis TR50 isolato da salame artigianale

Bacillus subtilis TR50 isolated from a traditional sausage, was selected for its technology properties. In order to evaluate its antimicrobial activity, cell-free supernatant of TR50 culture in PDB for 7 days (7-CFS) was concentrated and assayed by diffusion test against ten different food-borne bacterial pathogens. Overall, very large inhibition halos (241 mm2, on average) were found in lawns of S. aureus NCTC 8325, Y. enterocolitica DSM 4780, and A. hydrophila DSM 30187 seeded in agar medium. The treatment of 7-CFS with chymotrypsin reduced the inhibitory activity against all target strains, whereas lipase hydrolysis abolished only that displayed against A. hydrophila DSM 30187. These results suggest TR50 could produce different active compounds of proteinaceous nature, requiring a lipid moiety. Most of active peptides were precipitated with ammonium sulphate retaining 62% of total 7-CFS activity. These results make B. subtilis TR50 a promising candidate for improving the quality and safety of fermented meat products.