Recently an article was published in the American Journal of Nutrition detailing the gluten content of a variety of different gluten-free foods available for sale across several European countries.
Reassuringly, the study found that the overwhelming majority of products available were not only below the Codex Alimentarius guidelines of 20ppm or less detectable gluten, but had no detectable gluten at all.
However, the study itself only included one type of analysis: the R5 Sandwich ELISA. While this is no doubt the most popular analysis for gluten detection, it isn’t the only one. The R5 antibody does not necessarily tie toxicity to a positive result (detection of gluten), and so the possibility exists that a food testing negative for gluten with this method could in fact still be toxic for people with celiac disease.
For more, read the editorial (as a PDF and published in the American Journal of Clinical Nutrition) about gluten-free food and its safety for celiac patients.