Fig 1.
Typical colony morphologies of probiotic isolates grown on agar media.
(A) Bacillus coagulans on MRS agar, (B) Bacillus subtilis on TSA, (C) Lactobacillus plantarum on MRS agar, (D) Lactobacillus rhamnosus on MRS agar, (E) Saccharomyces boulardii on SDA agar.
Table 1.
Number of species identifications matching probiotic ingredient label.
Table 2.
Species identifications of probiotic microbes using three methods.
Fig 2.
Phenotypic profiling of probiotic bacteria and yeast.
(A) Probiotic bacteria Biolog results: Utilization of carbon sources (sugars). (B) Probiotic bacteria Biolog results: Utilization of carbon sources (other). (C) Probiotic bacteria Biolog results: Tolerance to compounds (Antibiotics, other). (D) Probiotic bacteria: Antibiotic susceptibility testing. Key for Disc diffusion: S = sensitive, I = intermediate, R = resistant. (E) Probiotic yeast Biolog results: Utilization of carbon sources. Wells of the yeast (YT) plate in Fig 2E contain different carbon sources than the same numbered wells of the Biolog GenIII plate for bacteria. Key for Biolog wells: P = positive, h = half (borderline positive/negative), (-) = negative. Note: only 47 of the 71 carbon sources on the GenIII plate are displayed in Fig 2A and 2B; the wells G1-8, H1-8, and Column 9 were mostly negative and are not shown.
Fig 3.
(A) Bacillus coagulans (no Biolog ID), (B) Bacillus subtilis, (C) Lactobacillus plantarum, (D) Lactobacillus rhamnosus.
Table 3.
Strain identifications listed on probiotic product labels.
Fig 4.
Species in this study and abundance in products for sale by major online retailer.
(A) Left: Bacteria and yeast isolated from probiotic products in this study (total = 20). Right: Number of products listed on Amazon.com containing the selected species of probiotic microbes.