Abstract

Six commercially available infant formulas (IF) without added prebiotic, were investigated as substrates for the growth of bifidobacteria isolated from the feces of 3 day old babies. This investigation tracked, during 48 h, the microbiological and biochemical changes in prepared infant formula meals, caused by the action of bifidobacteria, isolated from babies’ feces. Pancreatin digestion preceded inoculation of the bifidobacteria biomass. The reference substrate was mature breast milk. This investigation showed important differences in bifidogenic effect between individual infant formulas and mature breast milk. In relation to dry biomass from the mature breast milk, dry biomass obtained in individual infant formulas ranged from 71.4% (IF-1) to 34.6% (IF-6). The results showed that, with the similar declared nutritive and biological characteristics, there are important differences between individual infant formulas. The results obtained showed that, an  in vitrobifidogenic index test which covers tracking of microbiological and biochemical changes should be developed as a usefull tool in determining the suitability of infant formulas and it should be one of the first steps before clinical investigations.

Key words: Infant formula, bifidobacteria, prebiotics, bifidogenic effect.

Abbreviation

BI, Bifidogenic index; BML, bifidobacteria medium with lactulose;DBM, dry biomass; IF, infant formula; MBM, mature breast milk; MRAL, mole ratio of acetic and lactic acid; TNB, total number of bifidobacteria; TOA, total organic acids.