Microbial characterization of sourdoughs for sweet baked products

Samples of mother sponges for the production of some Italian cakes (Panettone, Colomba, Veneziana, Brioche and Cornetto) manufactured in 10 small and industrial bakeries located in Lombardy were investigated. According to traditional practices the doughs were prepared from a beginning sourdough, called "mother", propagated in a constant and definite way, A high degree of acidification occurred in the doughs with pH values of 3.67-4.10 and total titratable acidity 8.3-13.9 S degrees; the lactic acid concentration ranged from 7.69 to 15.73 g/kg and the acetic acid concentration from 0.76 to 1.25 g/kg. Microflora was composed of lactobacilli (10(7)-10(8) CFU/g) frequently ascribed to Lactobacillus sanfranciscensis species, and yeasts (10(6)-10(7) CFU/g) often belonging to Candida holmii species; coliform counts were <10 CFU/g, moulds <10(3) CFU/g, non-lactic acid bacteria <10(3)-10(4) CFU/g, Results confirmed that in sourdoughs for sweet baked products a strict association between characteristic microbial forms was maintained as a consequence of strictly observed and repeated conditions of fermentation, The identification of the strains of L. sanfranciscensis performed with a species-specific PCR procedure with 16S rRNA-targeted primers proved valid since results agreed with conventional methods based on phenotypic: analysis.