Abstract

MAYORGA-REYES, L. et al. Growth, survival and adaptation of Bifidobacterium infantis to acidic conditions. Rev. Mex. Ing. Quím [online]. 2009, vol.8, n.3, pp.259-264. ISSN 1665-2738.

Acidity is an environmental condition commonly encountered by bacteria in the gastrointestinal tract and fermented foods. In the present study, Bifidobacterium infantis cells were inoculated in culture media with initial pH of 7.0, 4.0, 3.0 and 2.0 respectively for 24 h. As the initial pH decreases, the active cell population decreased to three orders of magnitude. At pH 4.0 the cells were maintained stable during the first 5 h of fermentation. In addition, cells adapted to low pH were smaller than the original strain. The acid pH-adapted strains showed low expression levels of two membrane proteins of approximately 18 to 20 kDa.

Keywords : Bifidobacterium; acid resistance; probiotic.