The direct effect of probiotics in the lumen include the competition with pathogens for nutrients, production of antimicrobial substances and in particular organic acids competitive inhibition on the receptor sites, change in the composition of mucin hydrolysis of toxins, receptor hydrolysis, and nitric oxide (NO). The indirect effect of probiotics largely depends on the site of interaction between the probiotic and the effectors of the immune response. Thantasha et al., presented the number of specific properties or criteria a microbial strain has to fulfill in order for it to be regarded as a probiotic
