Synergistic effects of probiotic Leuconostoc mesenteroides and Bacillus subtilis in malted ragi (Eleucine corocana) food for antagonistic activity against V. cholerae and other beneficial properties.

Finger millet (Elucine corocana), locally known
as ragi, and probiotics have been recognized for their health
benefits. In the present work we describe novel probiotic
ragi malt (functional food) that has been prepared using ragi
and probiotic Leuconostoc mesenteroides (Lm) and Bacillus
subtilis natto (Bs), alone and in combination, for antagonistic
activity against Vibrio cholerae (Vc). In vitro studies
using pure cultures showed that each probiotic strain (Lm
or Bs) was able to inhibit the planktonic growth of Vc as
well as its ability to make biofilms and adhere to extracellular
matrix proteins (fibronectin, Fn) that may function in
vivo as initial ports of entrance of the pathogen.
Interestingly, the combination of both probiotic strains (Lm
plus Bs) produced the strongest activity against the Vc.
When both cultures were used together in the ragi malt the
antimicrobial activity against Vc was enhanced due to synergistic
effect of both probiotic strains. The inclusion of both
probiotic strains in the functional food produced higher
amounts of beneficial fatty acids like linoleic and linolenic
acid and increased the mineral content (iron and zinc). The
viability and activity of Lm and Bs against Vc was further
enhanced with the use of adjuvants like ascorbic acid,
tryptone, cysteine hydrochloride and casein hydrolysate in
the ragi malt. In sum, the intake of probiotic ragi malt
supplemented with Lm and Bs may provide nutrition, energy,
compounds of therapeutic importance and antagonistic
activity against Vc to a large extent to the consumer.