Microbiological quality during storage of pork balangu inoculated with nisin producing Lactococcus lactis subsp. lactis

Olaoye, O. A.; Onilude, A. O.; Ubbor, S. C.; Agiriga, A .N.

Introduction. The aim of this study was to characterize Lactococcus spp. isolates from pork balangu and use suitable strain in the biopreservation of the product. Materials and methods. Isolation of Lactococcus isolates was carried out using traditional methods while their presumptive identities were obtained using phenotypic method involving biochemical reactions. Their full identification was obtained by the use of 16S rDNA sequencing. Production of antimicrobial agents was done by the use of reported methods. The abilities of suitable isolate(s) to control spoilage and pathogenic organism of food origin were examined. Results and discussion. Thirty four Lactococcus spp. were isolated from pork balangu; their phenotypic characterization revealed they were composed of seven groups, members of which shared similar biochemical reactions. The phenotypic identities of seven isolates of the Lactococcus isolates, including one from each group, were confirmed by their 16S rDNA sequencing as L. raffinolactis, L. garviae, L. lactissubsp. cremoris, L. lactis subsp. hordniae, L. lactis subsp. lactis, L. plantarum and L. piscium. Among them L. lactis subsp. lactis produced higher concentration of lactic acid (21,45 g/10<^>7 CFU) than others, and also produced nisin (~ 608 bp), active against the spoilage organism of meat Brochothrix thermosphacta. Inoculation of nisin producing L. lactis subsp. lactis in pork balangu showed 4 log reductions in the counts of Listeria monocytogenes and B. thermosphacta from their initial 6 log in the meat product in situ. Conclusion. The nisin producing L. lactis subsp. lactis could be used in the shelf life extension of pork balangu beyond the day of production. The Lactococcus strain could therefore be applied as biopreservative culture to promote safety of meat products in West Africa and other parts of the world.


	Наукова періодика України		Ukrainian food journal