Lactobacillus casei is a species of genus Lactobacillus found in the human intestine and mouth. This particular species of Lactobacillus is documented to have a wide pH and temperature range. A specially selected strain of Lactobacillus casei is available as a culture concentrate or as part of a multiple strain custom blend with a variety of excipients. It is available as white, to cream-colored, free-flowing powder. Lactobacillus casei is a gram-positive rod of varying lengths, commonly occurring in short chains.