Fermentation of Milk • All fermented milk contains lactic acid • Undesirable (spoiled products) • Desirable (buttermilk, yogurt, cheese) − streptococcus lactis initiates the process with lactobacilli spp. continuing the fermentation − Increased thickness due to the association of casein micelles, often accompanied by ß- lactoglobulin.Fermentation of Milk • All fermented milk contains lactic acid • Undesirable (spoiled products) • Desirable (buttermilk, yogurt, cheese) − streptococcus lactis initiates the process with lactobacilli spp. continuing the fermentation − Increased thickness due to the association of casein micelles, often accompanied by ß- lactoglobulin