Quantitative estimation of antimicrobials produced by Lactic Acid Bacteria isolated from Nigerian beef

The evaluation of five strains of Pediococcus, isolated from Nigerian beef in a previous work, for the production of various antimicrobials is being reported in the present study. The objective was to assess the potential of the strains for use as biopreservatives in food preservation techniques, especially meat processing. The strains tested were Pediococcus pentosaseus LIV01 (GenBank accession number EU667381), Ped. acidilactici FLE01 (Accession number EU667382), Ped. acidilactici FLE02 (Accession number EU667385), Ped. pentosaceus INT02 (Accession number EU667384), and Ped. pentosaceus INT01 (Accession number EU667383). The methods involving high performance liquid chromatography, gas chromatography–mass spectrometry and peroxidise enzyme were adopted to assay for production of the antimicrobials - organic acids, diacetyl and hydrogen peroxides respectively, by the Pediococcus strains. All figures obtained for the concentrations of lactic and acetic acids were normalised as g/10^7 CFU while those of hydrogen peroxides and diacetyl as μg/10^7 CFU. Generally, lactic acid production increased with incubation time for all the isolates; the highest production of 28.02 g/10^7 CFU was recorded for Ped. pentosaceus INT01, followed by 23.37 g/10^7 CFU for Ped. pentosaceus INT02 within 42 h. The concentrations of acetic acid produced by the isolates were lower compared to those of lactic acid. Diacetyl was produced in minimal amounts, and the highest concentration of 57.89 μg/10^7 CFU was recorded for Ped. pentosaceus INT02. It was concluded that the Pediococcus strains could serve as promising candidates for use as protective cultures in meat preservation processes, based on their levels of production of the various antimicrobials. The higher production of diacetyl by Ped. pentosaceus INT02, in comparison to other strains, may be of particular interest when selecting candidates as biopreservatives for food bioprocessing.