- The coagulated milk product obtained by lactic acid fermentation through the action of Lactobacillus delbrueckii ssp. bulgaricus (Lactobacillus bulgaricus) and Streptococcus thermophilus from milk and milk products
- Other bacteria may be involved in the traditional fermentation of yogurt
- Inadequate pasteurization or the use of raw milk may introduce contamination with Salmonella, Listeria monocytogenes, Campylobacter jejuni, Yersinia enterocolitica, pathogenic strains of Escherichia coli, and enterotoxigenic strains of Staphylococcus aureus