title: Validating bifidobacterial species and subspecies identity in commercial probiotic products.
abstract: BACKGROUND
  The ingestion of probiotics to attempt to improve health is increasingly common; however, quality control of some commercial products can be limited. Clinical practice is shifting toward the routine use of probiotics to aid in prevention of necrotizing enterocolitis in premature infants, and probiotic administration to term infants is increasingly common to treat colic and/or prevent atopic disease. Since bifidobacteria dominate the feces of healthy breast-fed infants, they are often included in infant-targeted probiotics.
  
  
  METHODS
  We evaluated 16 probiotic products to determine how well their label claims describe the species of detectable bifidobacteria in the product. Recently developed DNA-based methods were used as a primary means of identification, and were confirmed using culture-based techniques.
  
  
  RESULTS
  We found that the contents of many bifidobacterial probiotic products differ from the ingredient list, sometimes at a subspecies level. Only 1 of the 16 probiotics perfectly matched its bifidobacterial label claims in all samples tested, and both pill-to-pill and lot-to-lot variation were observed.
  
  
  CONCLUSIONS
  Given the known differences between various bifidobacterial species and subspecies in metabolic capacity and colonization abilities, the prevalence of misidentified bifidobacteria in these products is cause for concern for those involved in clinical trials and consumers of probiotic products.
authors.affiliation: Department of Food Science and Technology, University of California, Davis, California.|Foods for Health Institute, University of California, Davis, California.
authors.forename: Zachery T
authors.initials: ZT
authors.lastname: Lewis
authors.affiliation: Department of Food Science and Technology, University of California, Davis, California.|Foods for Health Institute, University of California, Davis, California.
authors.forename: Guy
authors.initials: G
authors.lastname: Shani
authors.affiliation: Department of Food Science and Technology, University of California, Davis, California.|Foods for Health Institute, University of California, Davis, California.
authors.forename: Chad F
authors.initials: CF
authors.lastname: Masarweh
authors.affiliation: School in Science and Technologies for Health Products, University of Modena and Reggio Emilia, Italy.
authors.forename: Mina
authors.initials: M
authors.lastname: Popovic
authors.affiliation: Department of Food Science and Technology, University of California, Davis, California.|Foods for Health Institute, University of California, Davis, California.
authors.forename: Steve A
authors.initials: SA
authors.lastname: Frese
authors.affiliation: Department of Food Science, University of Massachusetts, Amherst, Massachusetts.
authors.forename: David A
authors.initials: DA
authors.lastname: Sela
authors.affiliation: Foods for Health Institute, University of California, Davis, California.|Department of Pediatrics, University of California, Davis, California.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Underwood
authors.affiliation: Department of Food Science and Technology, University of California, Davis, California.|Foods for Health Institute, University of California, Davis, California.
authors.forename: David A
authors.initials: DA
authors.lastname: Mills
mesh_terms: D015373:Bacterial Typing Techniques; D001644:Bifidobacterium / Q000145:classification / Q000235:genetics*; D004269:DNA, Bacterial / Q000032:analysis; D020345:Enterocolitis, Necrotizing / Q000517:prevention & control*; D005243:Feces / Q000382:microbiology; D016680:Genome, Bacterial; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature; D012150:Polymorphism, Restriction Fragment Length; D019936:Probiotics / Q000627:therapeutic use*; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D004269:DNA, Bacterial