Bifidobacterium lactis

Figure 1. Microscopic image of Bifidobacterium.

Bifidobacterium lactis (or Bifidobacterium animalis subspecies lactis) is a gram-positive, anaerobic, rod-shaped bacterium of the Bifidobacterium genus which can be found in the large intestines of most mammals, including humans. Bifidobacterium lactis is commonly recognised as a "good bacteria" residing within the human intestinal tract and helps break down food, absorb nutrients, and fight off "bad bacteria" that might cause diseases.

Bifidobacterium animalis and Bifidobacterium lactis were previously described as two distinct species. Presently, both are considered Bifidobacterium animalis with the subspecies Bifidobacterium animalis subspecies animalis and Bifidobacterium animalis subspecies lactis.

Bifidobacterium lactis is frequently used in Probiotics as a dietary supplement which, when consumed, helps in improving or restoring gut flora. It is one of the more robust species of Bifidobacterium bacterium. Amongst other characteristics, Bifidobacterium lactis exhibits elevated oxygen tolerance, enabling it to survive in a wider range of environments. This probiotic species has also been shown to inhibit the toxic effects induced by the wheat protein gliadin, a component of wheat gluten.

Both old names Bifidobacterium animalis and Bifidobacterium lactis are still used in Probiotic product labels. In such cases, the subspecies that is being used in the product will not be clear.

For nutritional values, refer to the Codex entry for Probiotics.