Taxonomy Notice: The name Bifidobacterium lactis is a deprecated synonym. This species was reclassified as Bifidobacterium animalis* subsp. *lactis by Masco et al. (2004) based on DNA-DNA hybridization and genomic analysis. The current accepted nomenclature per LPSN (List of Prokaryotic Names with Standing in Nomenclature) and NCBI Taxonomy is B. animalis subsp. lactis. Many commercial probiotic labels continue to use "B. lactis" as a consumer-friendly name.
For the full species profile, strain data, and clinical evidence, see: Bifidobacterium animalis subsp. lactis
Commercial Strains Listed Under "B. lactis"
The following strains are commonly marketed under the B. lactis name but are correctly classified as B. animalis subsp. lactis:
- BB-12 (Chr. Hansen, DSM 15954) — the most studied probiotic strain globally, with 300+ publications covering immune support, digestive regularity, and infant health[1]
- HN019 (IFF/DuPont, AGAL NM97/09513) — gut transit time, immune enhancement in elderly
- DN-173 010 (Danone, CNCM I-2494) — constipation relief, marketed as Activia
- B420 (IFF, DSM 32269) — body fat reduction, metabolic health
- Bi-07 (IFF) — lactose digestion support, pediatric immune health
- CECT 8145 (Spanish Type Culture Collection) — abdominal obesity, postbiotic applications
All clinical evidence, strain cards, and detailed profiles are maintained on the canonical entry: Bifidobacterium animalis subsp. lactis
Why the Name Change?
Bifidobacterium lactis was originally described by Meile et al. (1997) as a novel species isolated from fermented milk. In 2004, Masco et al. demonstrated through DNA-DNA hybridization that B. lactis and B. animalis share sufficient genomic similarity to be considered subspecies of the same species, leading to the reclassification as B. animalis subsp. lactis.
The name B. lactis persists in commerce because:
- Regulatory submissions were filed under the original name
- Consumer recognition of "lactis" implies dairy/probiotic association
- Many national regulations grandfather previously approved species names
For microbiome testing purposes, results reported as B. lactis and B. animalis subsp. lactis refer to the same organism.