What is Lactobacillus Casei? Lactobacillus casei powder is a probiotic additive containing the Lactobacillus casei subsp.casei and a special protective agent.It is a mesophilic bacteria that is gram-positive, rod-shaped, non-sporing, non-motle, anaerobic, and contains non-cytochromes. Lactobacillus casei subsp.casei is shown to have remarkable tolerance for the harsh acids normally found in the stomach and digestive tract. Intake of Lactobacillus casei subsp.casei …