Gluten Contamination Levels of Oat Products Labeled Gluten-Free: Summary Test Results from Gluten Free Watchdog

Gluten Contamination Levels of Oat Products Labeled Gluten-Free: Summary Test Results from Gluten Free Watchdog

Over the past five years Gluten Free Watchdog has tested 35 different oat products labeled gluten-free that list oats as the first or second ingredient. Bottom line: Based on testing data from Gluten Free Watchdog, oat products labeled gluten-free are at a higher risk of gluten contamination as compared to labeled gluten-free foods as a whole.

  • 28/35 or 80% of oat products tested below 5 parts per million of gluten.
  • 5/35 or 14% of oat products tested at or above 20 ppm of gluten
  • 2/35 or 6% of oat products tested at or above 5 ppm but below 20 ppm of gluten

Note: Approximately 5% of all gluten-free foods tested to date through Gluten Free Watchdog have tested at or above 20 ppm of gluten. The percentage of oat products testing at or above 20 ppm of gluten (i.e., 14%) is higher than for gluten-free foods in general.

Products testing at or above 20 ppm of gluten [testing conducted by Bia Diagnostics, LLC using the sandwich R5 ELISA (Ridascreen Gliadin R7001) and cocktail extraction (Mendez method)]:

  • Oat breadcrumbs. Extractions ranged from 9 ppm to > 84 ppm of gluten
  • Rolled oats. Extractions ranged from 72 ppm to > 84 ppm of gluten
  • Granola. Extractions ranged from < 5 to 50 ppm of gluten
  • Hot oat cereal. Extractions ranged from 18 to 73 ppm of gluten
  • Granola. Extractions ranged from 16 to 26 ppm of gluten

Note: Based on conversations with the manufacturers of products testing at or above 20 ppm of gluten, oats from suppliers of purity protocol oats were not being used in these five products at the time of original testing. Four of the manufacturers have changed or are in the process of changing oat suppliers. Three of these products have been retested for gluten contamination. These products are now testing below 5 ppm of gluten. One of the manufacturers chose to stop labeling product gluten-free.  

Manufacturer recommendations:

  • Know your oats! Make sure you are sourcing oats from a supplier of purity protocol oats (e.g., GF Harvest, Avena, Montana Gluten-Free). At this time Gluten Free Watchdog does not recommend any of the commercial suppliers of mechanically and optically sorted oats (e.g., Grain Millers, LaCrosse Milling).
  • Ask for test results. Regardless of where you source oats, ask your supplier to provide you with test results, including how frequently oats are tested and what assay is used for testing.
  • Test the oats. There is no such thing as too much testing. Send samples of oats to a third party lab for testing using the sandwich R5 ELISA and cocktail extraction. Labs include Bia Diagnostics and FARRP.

Consumer recommendation:

  • Know the source of the oats you are eating. If a manufacturer will not answer the question, “Do you source ALL of your oats from a supplier of purity protocol oats” don’t eat the oats (if purity protocol oats are important to you).

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Comments (16)

  • Holly Salmon Reply

    Tricia, I can’t tell you what it means to have you on our side in the gluten-free community. It is really hard to stay healthy and feel good and you’re part of the reason I do right now.

    May 18, 2016 at 3:42 pm
  • carrie ek Reply


    Thank you so much for doing all this hard work and being brave enough to tell the truth!. You are such an important part of keeping people with celiac eating safely.

    May 18, 2016 at 4:16 pm
  • Jonathan Hartley Reply

    Thanks so much for the post, and all the less-visible mountain of work that must be behind it.

    Is it possible for you to summarise which brands you recommend, and those you don’t? I can understand if you think publishing such a list might be unhelpful, especially if manufacturers are in the process of changing suppliers or processes. But from the practical standpoint of just wondering what I should buy when I’m next in the supermarket, that seems most useful to me. (Maybe you already maintain such a list somewhere else on the site, and I’m just not finding it?)

    May 18, 2016 at 5:58 pm
  • Emily Gamache Reply

    Thank you so much! We steer clear of most but we do have Kind breakfast bars and Gluten Frieda oatmeal. Can you please tell me if these are safe? Thank you!

    May 23, 2016 at 9:56 pm
  • Ron Hoggan Reply

    Thanks for the important work you do Tricia.
    best wishes,
    Ron Hoggan

    June 5, 2016 at 9:32 pm
    • Tricia Thompson Reply

      My pleasure, Ron. Thanks for taking the time to comment.

      June 6, 2016 at 5:12 pm
  • jst Reply

    Just discovered this resource while trying to figure out a serious reaction this morning. I’m a diagnosed celiac and, perhaps foolishly, accepted the labeling of GF Cheerios without further research. Nothing else I ate that could possibly have been to blame. I note that the article I read was from a year ago and wonder if there is an update on ‘GF’ Cheerios. Thanks.

    July 18, 2016 at 4:58 pm
    • Tricia Thompson Reply

      We have not done any additional testing of “gluten-free” Cheerios. We have reached out to General Mills asking if there have been any changes to their sorting and testing practices.From what I understand they are working on a response.

      July 18, 2016 at 5:57 pm
      • jst Reply


        July 18, 2016 at 9:14 pm
  • Dodi Reply

    About a month ago I purchased a box of GM Cheerios and didn’t connect the dots until this week and noticed every time I eat a bowl of the GM cheerios I break out and/or feel an upset stomach. I Get so frustrated of this deceptive labeling.
    Thank you Tricia for zeroing in on and keeping us up to date.

    December 10, 2016 at 5:37 pm

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