Abstract

Fermented foods have been associated with probiotics: microorganisms that are useful to the host. The potential probiotic characteristics of Lactobacillus plantarumand Lactobacillus rhamnosus strains isolated from ikii, a traditional fermented maize porridge, were studied and with regard to acid/bile tolerance, antimicrobial activity, utilisation of fructooligosaccharide, production of exopolysaccharides and safety attributes. Out of 19 strains of L. plantarum and one L. rhamnosus, 18 strains of L. plantarum were able to tolerate pH 2 for a period of 3 h. All the L. plantarum and L. rhamnosus strains assayed tolerated pH 2.5 for a period of 3 h, population counts remaining at levels of between 5 to7 log cfu/ml. Following 3 h exposure to pH 2, 18 L. plantarum strains were able to tolerate and grow to levels between 5 and 6 log cfu/ml in MRS supplemented with 0.3% bile salts within a period of 24 to 48 h. Sixteen (16) strains of L. plantarum exposed to pH 2.5, were able to grow to levels of 5 and 7 log cfu/ml in MRS broth supplemented with 0.3% bile within a period of 24 to 48 h. The assayed strains showed antimicrobial activity against E. faecalis, S. aureus and E. coli. Two (2) strains of L. plantarum were able to utilise a fructooligosaccharide. All 20 strains were able to produce exopolysaccharides. None of the assayed strains showed haemolytic and gelatinase activity. It is therefore possible that L. plantarum involved in production ofikii do have potential probiotic attributes.

Key words: Probiotics, Lactobacillus plantarum, Lactobacillus rhamnosus, acid/bile tolerance, antimicrobial activity, exoplysaccharides, fructooligosacharides.