LAUSR

B ACTERIA, MOLD, YEAST, AND enzymes produced by bacteria are used in a variety of products, including probiotics and digestive enzymes. These microorganisms may be grown on media that may include ingredients derived from gluten-containing grain (ie, wheat, barley, and rye). According to the International Probiotics Association, “probiotic bacteria require complex growth media that contain a range of ingredients.” According to Deerland Enzymes, the enzymes used in supplements may be produced from fermented bacteria grown on wheat. In addition, the bacteria Xanthomonas campestris used to make xanthan gum may be grown on wheat glucose syrup, and the mold Penicillium roqueforti used to make blue-veined cheeses may be grown on wheat or barley-derived media. Historically, some concern has been expressed in the celiac disease community that the use of gluten-derived/ gluten-containing growth media may result in residual gluten protein fragments remaining in products containing microorganisms such as bacteria and mold. Regardless, a Canadian Celiac Association analysis of gluten-derived growth media used to grow Penicillium roqueforti found gluten to be below the limit of detection using the sandwich and competitive R5 enzyme-linked immunosorbent assays (ELISAs; RBiopharm R5 ELISA Ridascreen Gliadin and R-Biopharm R5 ELISA Ridascreen Gliadin Competitive, respectively). In addition, Xanthomonas campestris grown on wheat glucose syrup and tested with both the sandwich and competitive R5 ELISAs tested below the limit of quantification for gluten.* However, an abstract presented at Digestive Disease Week in 2014 further increased concerns about growth media. This study assessed the gluten content of probiotics, including 15 that were labeled as gluten free. Two of the labeled gluten-free products contained more than 20 parts per million (ppm) of gluten based on liquid chromatographymass spectrometry. In the United States, Food and Drug Administration (FDA)regulated foods, including supplements, must contain less than 20 ppm gluten to be labeled as gluten free. One obstacle preventing the resolution of whether residual gluten sometimes remains in products containing bacteria and mold is the general lack of readily available information on the growth media used to cultivate these microorganisms. Although the bacterial or mold strains present in probiotics, enzymes, supplements containing probiotics or enzymes, and some fermented foods is declared, no information on the growth media is typically provided. All of this makes knowing the specific commercial products to target for testing difficult.