A recent study by scientists at the University of California, the University of Massachusetts, and the University of Modena and Reggio Emilia (Italy) reported that contents of many bifidobacteria probiotic products differ from the ingredients listed.
“These results suggest that quality control of probiotics is lacking,” they wrote.
Common methods have difficulty distinguishing between two subspecies of Bifidobacterium longum - B. longum subsp. longum and B. longum subsp. infantis, said the researchers.
Writing in the journal Pediatric Research (doi:10.1038/pr.2015.244), the scientists report the use of a reliable and inexpensive DNA-based method to accurately differentiate between the two subspecies. Our full coverage of the study can be found HERE.
In a statement sent to NutraIngredients-USA, the International Probiotics Association said that product quality is at the heart of the trust that exists between manufacturer and consumer.
“The report by Lewis and co-workers  therefore raises concern; according to the authors, only one out of 16 tested probiotic products confirmed the label claim,” read the IPA's statement.
“The closely related subspecies of Bifidobacterium longum, B. longum ssp. infantis and B. longum ssp. longum, cannot be discriminated based on 16S RNA gene analysis. For that, the technique developed by Lewis and co-workers  could be very useful. The authors developed a molecular-based technique to distinguish various species of bifidobacteria. With this, they tested 16 commercial products and determined the content comparing two pills from two different lots.
“The study notes pill-to-pill and lot-to-lot variation. Unfortunately, we do not know what the variation within the utilized technique is, what part of the observed variation is due to the technique and what is due to actual product variation?
“Also, the detection limit of the technique used is not mentioned. The original paper on the applied technique does not refer to this topic either . However, the paper describing the used technique does acknowledge that minor components may not be picked up. This could explain some, but not all, of the reported discrepancies. It is not unusual for products containing combinations of strains to have some of the strains present at relatively low concentrations; compared to the major components.
“IPA is committed to high probiotic quality and therefore welcomes and supports further development and validation of this (or any other) technique and establishment of an independent quality control laboratory which could carry out this type of analysis.”
 Lewis ZT, et al. “Validating bifidobacterial species and subspecies identity in commercial probiotic products” Pediatric Research. 2015, doi:10.1038/pr.2015.244.
 Lewis ZT, et al. “Use of bifidobacterial specific terminal restriction fragment length polymorphisms to complement next generation sequence profiling of infant gut communities”. Anaerobe. 2013, Vol. 19, pp. 62-69, doi: 10.1016/j.anaerobe.2012.12.005