Cultivation, isolation and characterization of bacteriocin from fresh cow milk and meat samples obtained from Lapai Market in Niger State Nigeria
This study focus on cultivation, isolation and characterization of Bacteriocin from fresh cow milk (FCM) and fresh cow meat (FMS) samples obtained from Lapai Market in Niger State, Nigeria. Potential bacteriocinogenic bacteria were screened with agar diffusion method on culture plates seeded with Staphylococcus and E.coli. Bacteriocinogenic isolates from FCM were Enterococcus faeciumFCM5 and Bacillus megaterium FCM6, while isolates from FMS include Bacillusbadius FMS1 and Micrococcus varians FMS2. Bacteriocins produced were assayed with pre-enriched MRS broth culture incubated at 300C with adjusted pH (7.1) for 48 hrs and stored (40C). The primed cultures were centrifuged (20,000rpm) for 30mins, supernatant were filtered (0.2μm membrane filters), precipitated with ammonium sulphate and steam sterilized (121 0C at 15psi) for 15mins. Bacteriocin-like products (BLPs) were crystallized and tagged enterocin FCM5, bacillocin FCM6, bacillocin FMS1 and micrococin FMS2 according to bacteriocinogenic isolates' typing. After 48 hrs, Bacteriocinogenic load ranged between 5.1 - 6.13Log10 cfu/mL. Biopreservative indexes (BI) of BLPs (0.25 - 0.75 mg/mL) were effective against predominant food spoilers (Saccharomyces, Pseudomonas, Klebsiella and Micrococcusspp isolated from range of beverages, starchy and meaty meals). Quantified BLPs (20 - 1880 IU/mL) strengths had no direct correlation with the antibacterial spectral (6 - 19mm) expressed as zone of inhibition. Thus, efficacy of BLPs observed in this study, were not a function of BLP quantity but quality. Conclusively,Enterocin FCM5, Bacilliocins (FCM6 and FMS1) and Micrococin FMS2 are thermal and pressure stable BLPs that are effective against predominant food spoilers.
Keywords: Bacteriocin, cultivation, milk, meat, Lapai, bacteriociongenic