Comparative Studies in the Manufacturing of Acidophilus, Bifidus and Acido-bifidus Milks

The “Encyclopedia of Fermented Fresh Milk” has classified Acidophilus and Bifidus milks as Non-traditional fermented milk products. These products contain Lactobacillus acidophilus and Bifidobacterium spp., respectively, that are known as probiotic microoganisms. In this study, some aspects of acidity development, pH measurement and bacterial counts were monitored when these micro-organisms were grown in milk. The starter cultures of L. acidophilus La-5 and Bifidobacterium lactis Bb-12, obtained from Chr. Hansen in Denmark, were each inoculated at the rate of 0.01 g 100 ml-1 in UHT milk and incubated at 37ºC for a duration of 5 h (Acidophilus and Bifidus milks). The same procedure was carried out with the same inoculation rates of two mentioned starters as mixed culture (Acidobifidus milk). The titratable acidity measurements and pH values of the single strains fermented milks were similar, but the sour taste of Acido-bifidus milk of the mixed starter culture was more tangible when compared with the two other fermented products. From the limited data available, it was evident from the preliminary studies that the growth of B. lactis in mixed cultures was better as compared to the single strain, and it is suggested that a lower inoculum rate of starter cultures or shorter fermentation period might be recommended for the development of Acido-bifidus milk.