THE ANTIMICROBIAL ACTIVITY OF LACTIC-ACID BACTERIA FROM FERMENTED MAIZE (KENKEY) AND THEIR INTERACTIONS DURING FERMENTATION

A total of 241 lactic acid bacteria belonging to Lactobacillus plantar um, Pediococcus pentosaceus, Lactobacillus fermentum/reuteri and Lacto bacillus brevis from various processing stages of maize dough fermenta tion tt-ere investigated. Results indicated that-each processing stage has its own microenvironment with strong antimicrobial activity. Abou t half of the Lact. plantarum and practically all of the Lact. ferment um/reuteri investigated were shown to inhibit other Gram-positive and Gram-negative bacteria, explaining the elimination of these organisms during the initial processing stages. Further, widespread microbial in teractions amounting to 85% to 18% of all combinations tested were dem onstrated amongst lactic acid bacteria within the various processing s tages, i.e. raw material, steeping, 0 h and 48 h of fermentation, expl aining the microbial succession taking place amongst lactic acid bacte ria during fermentation. The antimicrobial effect was explained by the combined effect of acids, compounds sensitive to proteolytic enzymes and other compounds with antimicrobial activity with the acid producti on being the most important factor. The pattern of antimicrobial facto rs was not-species-specific and the safety and storage stability of fe rmented maize seem to depend on a mixed population of lactic acid bact eria with different types of antimicrobial characteristics. This means that introduction of pure cultures as starters may impose a risk to t he product.