Assessment of acid production by various human oral micro-organisms when palatinose or leucrose is utilized

One promising way of reducing caries is by using sucrose substitutes in foo d, e.g., palatinose or leucrose. Previous experiments addressing cariogenic potential of sucrose substitutes have focused mainly on Streptococcus muta ns. However, given the many other micro-organisms in the oral cavity, this study compared the acid production of 100 bacterial strains representing 44 different species, by batch fermentation in a test tube containing, as a s ole carbohydrate source, glucose, sucrose, palatinose, or leucrose. Selecte d strains were further analyzed in a fermenter. Additionally, 30 yeast stra ins were tested by an auxanographic sugar assimilation test. Only Lactobaci llus spp., Stomatococcus mucilaginosus, Leuconostoc mesenteroides, and Weis sella paramesenteroides, and some of the yeasts studied-i.e., Candida albic ans, C. tropicalis, C. parapsilosis, and Saccharomyces cerevisiae-utilized leucrose and/or palatinose well. Strikingly, Stomatococcus mucilaginosus pr oduced water-insoluble polysaccharides by fermentation of leucrose and pala tinose. In the fermenter, the respective sucrose substitutes were not only cleaved but also utilized. Thus, extracellular cleavage by autochthonous mi cro-organisms may produce cariogenic cleavage products (glucose, fructose) that can be used by other well-characterized cariogenic bacteria found in t he oral flora. Therefore, the anticariogenic potential of sucrose substitut es in food might be limited.