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 faecium
FCM5 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 30
0C with adjusted pH (7.1) for 48 hrs and stored (4
0C). 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.