This finding was aimed at investigating the characteristics of selected strains of lactic acid bacteria (LAB) being proposed for use as starter cultures for extending the shelf life of tsire, a Nigerian grilled meat product. The LAB strains used included Lactobacillus plantarum, Streptococcus lactis, S. bovis, Pediococcus acidilactici and Pediococcus sp., which were previously isolated from beef. The pH value of below 4.5 was recorded in growth medium of the LAB isolates. The highest concentration of lactic acid (2.9 mg/l) was recorded for L. plantarum, while Pediococcus sp. had the lowest (1.2). Acetic acid production was below 0.4 mg/l by all isolates. Proteolytic and lipolytic activities were not recorded by the strains, except Pediococcus sp. which recorded proteolytic activity of 0.03 unit/ml. Inclusion of spice combination consisting ground red pepper, tomato and onion in growth had a Mg2+ content of 17.1 ppm, and gave the highest support to the growth of LAB strains L. plantarum and S. lactis; values of 9.8 and 8.8 were obtained as log CFU/ml for the respective organisms. Tsire samples treated with cultures of L. plantarum and S. lactis and stored at 30oC had lower thiobarbituric acid and free fatty acid values than uninoculated control counterparts. It was concluded that non proteolytic and lipolytic activities with reduction in acetic acid production as well as relatively high production of lactic acid would constitute significant characteristics of LAB strains to be adopted as starter cultures in extending the shelf life of a Nigerian grilled meat product tsire. Optimization of spice combinations in medium of the LAB cultures may also affect their growth and metabolic activities towards production of useful antimicrobial compounds, especially lactic acid.
