Jump to content
  • Sign Up
  • Join Our Community!

    Get help in our celiac / gluten-free forum.

  • Dimitrios Douros
    Dimitrios Douros

    The Cross-Contamination Myth-Buster!

    Reviewed and edited by a celiac disease expert.

      Journal of Gluten Sensitivity Autumn 2014 Issue

    Caption: Photo: CC--Rex Hammock

    Celiac.com 08/22/2016 - The issue of cross-contamination keeps coming up in articles, conferences, blogs and every other venue in which celiacs discuss ways of living with our disease. For all the talk there has been precious little, if any, thoughtful analysis, so I felt it was time for one. Some will appreciate this analysis—others will not. For reference, I don't work for the food industry in any way, shape or form, so I'm not presenting arguments to help anyone make money. I just think that the way gluten permeates our food culture, we celiacs have become overly cautious and worried about where the next molecule of gluten may be hiding, ready to attack us, and as a result walk around in constant fear, significantly degrading our overall quality of our life and doing more harm to our health through stress than a rare, chance episode of cross-contamination might actually do.

    Using the FDA's 20ppm limit as the definition of gluten-free, and some simple, first grade arithmetic, I want to look at the cross-contamination issue and see what's worth worrying about and what's not.

    Because cross-contamination is a situational, process-related issue, it is best to separate the issue into categories that relate to the situation: a) at home, B) in food production lines shared with gluten products, c) at the prepared food counter in the local grocery store, d) in restaurants.

    What's E.coli Got to do With It?
    Cross-contamination at home is mostly an issue for someone just starting out on a gluten-free life and for those 'blended' families that have some individuals on a gluten-free diet and the rest of the family not.

    There have been many posts over the years with this sentiment: "I just got diagnosed with celiac disease, I have started on the gluten-free diet and other celiacs are telling me to get rid of most of my cooking utensils, especially wooden spoons, plastic spoons, basting syringes as well as brushes I use with oil and butter."

    The concern behind this statement is that porous wood and scratches in plastic spoons and syringes or the hairs of a brush can harbor gluten particles that can contaminate our food. A reasonable sounding argument on the face of it, but one that has absolutely no merit when examined in the light of science and reason!

    E.coli found in beef and salmonella found in chicken are living nasty organisms that multiply and spread and can cause health problems from mild GI upset to death in some cases. And yet there has never been a case of someone throwing away their kitchen utensils after cooking chicken or beef. The utensils—wood, plastic or otherwise—get washed and re-used. If we trust proper washing to get rid of nasty, living, growing organisms that can kill us, there is no reason to doubt that the same proper washing can get rid of some particles of gluten—a non-living, non-growing, non-spreading food ingredient.

    Playing the devil's advocate, let's assume that our washing left behind a thin layer of wheat flour on a wooden spoon—certainly an amount so small that cannot be seen, else it would have been wiped away. How much flour is that? The flour from one fifth of a grain of wheat is enough to completely cover the spoon. One fifth of a grain of wheat is 16mg of wheat; of which no more than 3mg is gluten. So let's assume we use that wooden spoon to prepare pasta in a 1-quart pot and all the flour on the spoon dissolves into the water with the pasta. That's 3mg of gluten in 1,000grams of water (1-quart = 1,000g of water). That works out to around 3ppm gluten in the pot. That is well below the 20ppm definition of gluten-free in the new FDA regulations; it is actually below any level today's best science can even measure! What's more, since we assumed that ALL the flour on the spoon dissolved into the water, the spatula is from now on, forever gluten-free, just as un-contaminated as a brand new spatula from the store!

    Moral of the story: either the washing will remove the gluten from the utensils, or the gluten left over will be below the 20ppm limit in the first food cooked with that utensil and leave the spoon completely uncontaminated ever after. So if you want to use gluten as an excuse to get some new cooking utensils, that's OK, but there is certainly no cross-contamination reason to do so. If you are really concerned, take all your utensils, put them in a pot of boiling water for 10 minutes and you're done! After all, that's how hospitals used to sterilize syringes before throw-away ones became the norm.

    Additionally this argument would indicate that a family that cooks both gluten-free and non-gluten-free could use one set of utensils as long as they get washed after every use. To feel more comfortable, one could use two sets of utensils, one for gluten-free the other for the rest.

    That's False Advertising—I'm Suing You!
    Cross-contamination concerns for foods from shared lines come up as we read food labels that say: "Prepared on a production line that also processes wheat and tree nuts."

    A couple of things to start the discussion: Making customers sick is a bad business plan, the only thing worse is having customers sue for severe illness or death. For these reasons food companies that use allergens in their products - wheat, milk, soy, nuts, shellfish, etc., take the precaution of cleaning their production lines between runs of different products to avoid the very cross-contamination that could sicken or kill their customers. However, in our extremely litigious society, even when a company knows its production line is clean and free of cross-contaminants, it is safer to simply slap the label: "Prepared on a production line that also processes wheat and tree nuts" on the product and completely avoid any nuisance lawsuit.

    Of course this leaves all of us celiacs scratching our heads trying to decide whether it's OK to consume such a product or not. Opinions vary; for my part, I note the label, keep it in mind, but operate on the basis that the company does have a standard process for cleaning their equipment between product runs.

    With that assumption, the only chance of cross-contamination is in the first few batches of the product to go through the line, batches that most, if not all, manufacturers test and discard if found to be cross-contaminated. Even if such a 'spot' contaminated batch made it through to the market the analysis would follow along the same lines as all other cases in this article. The amount of wheat flour (and therefore gluten) that is left on the processing line must be too small to even be seen, otherwise it would have been wiped away. That small amount spread over several 'units' of the product could only result in a few ppm gluten for each 'unit' of the product. Certainly not a cross-contamination concern.

    There's Gluten in Salmon! Really?
    Cross-contamination at the grocery store; primarily a problem in any of the many grocery stores that prepare foods on premises, like sushi and salads or getting fresh-sliced cold-cuts at a deli.

    Pick up a tray of salmon or tuna sushi - nigiri, sashimi, maki—and the ingredient list includes wheat, but the person that prepared it says they don't use wheat. Pick up a salad that obviously has no wheat in it and yet the label lists wheat as a potential allergen. What is going on?

    The most probable culprit in all such cases is the packet of condiments 'on the side'. Sushi almost always includes a sealed soy sauce packet or two for people to use if they want. As we celiacs know most soy sauce contains wheat so, the label on the entire sushi container—which includes the soy sauce packets—lists wheat because of the soy sauce. Skip the soy sauce and enjoy your gluten-free sushi! Same argument with a salad—if wheat is listed as an ingredient but there is no obvious wheat in the salad (croutons, bread, etc.) then the wheat listed is most probably in the dressing offered on the side—skip the dressing.

    Getting fresh cold-cuts at a deli to make sandwiches with your favorite gluten-free bread can raise the question of cross-contamination at the slicer from cured meat products that may contain gluten. First, any reputable deli wipes down their slicer between orders. To add a level of safety, explain the cross-contamination concern and ask the person preparing the order to set aside the first 5 slices—they will always oblige. Any residual gluten will stick to the first few slices and the rest will be fine.

    A Gluten Fog: Your Local Pizzeria—Not That Scary!
    We're all getting used to pizza places that have become enlightened enough to add gluten-free pizza options to their menu. They prepare gluten-free dough and cook the pizza in a dedicated corner of their oven or on baking sheets reserved for gluten-free pizzas. Giving them the benefit of the doubt that they spread out the toppings with no cross-contamination—which is easily checked by a few questions—this leaves one more cross-contamination concern. In 'high end' pizza places that roll their own dough for the regular (wheat) pizzas there's flour dust in the air. It would seem to be a valid cross-contamination concern, but the numbers are again, against it—unless the flour dust in the kitchen is so thick you can't see from one end of the kitchen to the other—not likely because flour dust that thick is a fire hazard!

    So the analysis again reveals a non-issue: the amount of flour dust that lands on a 10" pizza is less than one wheat grain's worth. That's 65mg of wheat, worst case that is 10mg of gluten which translates to less than 10ppm for the entire 10" pizza, again well below the 20ppm definition of gluten-free in the new FDA regulations! So if you're feeling GI distress after eating your favorite gluten-free pizza at your favorite pizzeria, it's probably the pepperoni!

    Salads at a restaurant are the next big concern because of the increasing tendency to see croutons or pita wedges as part of the salad. Of course you ask for your salad without the gluten item. And wouldn't you know it when the salad comes you see a big pita wedge right on top! Of course you ask that they take it back and bring you one without pita. And you wonder—did they make a new one or just serve you the old one after taking the pita off? Or maybe it's a business lunch with an important client and you don't want to make a fuss and don't even ask for a new salad. This is where my analysis goes a bit too far for some. I will remove the pita or pick around the croutons and eat the salad without a worry about getting 'glutened'. In my scientific brain the case is quite simple and clear: the thing we miss the most about gluten is its sticky property—it's a glue that sticks things together, and makes it possible to have light, airy, crusty baguettes to die for! Well, that same great property is what gives me the confidence to eat that salad. During baking, the gluten is completely bound up in that pita or in the croutons—it is not going to come loose just to contaminate me. It has not been laying in wait for the opportunity to be put on a celiac's plate and launch an attack on my villi—it's just not going to happen, nature does not work that way.

    So, worry a little less and enjoy a lot more! I leave you with this empirical fact: There was a report back in the late '90s about a 10-year research program that went around the world interviewing people that were in their 90's to try and find a common thread to their longevity. Every factor was considered, food, smoking, physical activity level, genetics, drinking—everything. Once all the data was analyzed there was one and only one, crystal clear, common factor among all these people: they knew how to let go of worry, stress, loss, pain. Regardless of what life threw at them, they moved past it to the other side and kept on going. Don't let unfounded, irrational fear of gluten rob you of your life—move past it!

    User Feedback

    Recommended Comments

    Gluten is sticky it sticks to things, unlike germs, which wash away, and or die over time. This argument is not accurate at all. It is dangerous; misinformation makes people sick. On a story like this, from a celiac group, accuracy is of extreme importance.

    Share this comment

    Link to comment
    Share on other sites

    Too broad a brush is used in examples for what might or might not make a difference in cross-contamination for Celiacs. The author is obviously one of those "mildly-affected" celiacs or simply gluten-intolerant or he would be aware that "a little gluten" is NOT okay. The motto, "When in doubt, do without," is much more celiac-friendly. Above and beyond the immediate impact of gluten exposure (unpleasant as it may be), the cumulative effect on the gut has serious medical consequences. The author of this article is being irresponsible and following his advice could cause harmful consequences for newly diagnosed celiacs.

    Share this comment

    Link to comment
    Share on other sites

    A few thoughts from me. The guy who wrote the article is an older guy, "in retirement." I find older generations think of gluten and Celiacs Disease as a hoax. Even if this guy believes it I've always found older people not really believing or understanding it. As said above already different people have different sensitivity levels to gluten and even cross contamination. Furthermore if you have celiacs disease wether you feel you're getting sick or not IT IS CAUSING DAMAGE internally. That's your choice if you choose to not live your life to the fullest and healthiest extent. Lastly as a mother of a kid with celiac and not a celiac myself I can't talk on the physical pain gluten causes my son. What I can talk on is seeing his scopes and watching him be in pain up to a week just purely miserable. As much as reading an article like this is supposed to change you and make you think you need to loosen the reigns a bit. I won't. We won't. Because I don't take chances with my sons health. Could he not get sick? Yes that's the whole thing with cross contamination. In the same sense could he get sick? Yes. So if there's a possibility of getting sick I stay away from it completely. Not a fan of this article.

    Share this comment

    Link to comment
    Share on other sites

    There seems to be a faction of people with mild celiac sensitivity who project their experience of the disease onto all celiacs. It is unhelpful and unwise to advise celiacs to ignore the possibility of cross contamination. Maybe the author is lucky and has perfect blood work after eating out. However, many of us are not so fortunate. It is well known that immune reactions are highly individual. When I eat even certified gluten free products my lab work comes back positive because my immune system sees it all. If this is not the case for you, great, go out and enjoy your life. But please don't take it for granted, and please remember that your experience is not the same as everyone. There are many with celiac disease who continue to suffer after going gluten free, and this author's attitude is dismissive at best.

    Share this comment

    Link to comment
    Share on other sites

    Finally something I've read that makes sense to me!  The writer is the first I have seen that understands the difference between a dimensionless quantity (ppm) and mass (mg).  Studies have shown the average (not the most sensitive) celiac can consume up to 20-50 mg of gluten per day.  If you are careful to eat only food that is inherently gluten free or below the 20ppm standard, you shouldn't have any problem staying below that amount even with 2 or 3 mg of cross contamination in the one meal you eat out or microscopic amount transferred from utensils.  If your limit is 1 mg per day this doesn't apply to you, but that is okay and it doesn't make it any less valid for the average case.

    I would not deny someone's symptoms and believe that what is being described by the super sensitive is real, but the general celiac community needs resources that aren't written ONLY by the ultra gluten sensitive.  There is a real negative effect of trying to have people who are celiac attempt (and fail) to live to the standards of the whole-food, ultra-gluten sensitive community.  The negative effect being that they will give up and suffer the consequences later.  That is why articles like this exist.  It isn't to belittle those who are more sensitive, but rather to encourage the average patient that they can live gluten-free successfully.

    Share this comment

    Link to comment
    Share on other sites

    Join the conversation

    You are posting as a guest. If you have an account, sign in now to post with your account.
    Note: Your post will require moderator approval before it will be visible.

    Add a comment...

    ×   Pasted as rich text.   Paste as plain text instead

      Only 75 emoji are allowed.

    ×   Your link has been automatically embedded.   Display as a link instead

    ×   Your previous content has been restored.   Clear editor

    ×   You cannot paste images directly. Upload or insert images from URL.

  • About Me

    In retirement from a fortune 500 company, I suddenly found myself diagnosed with celiac disease. I believe in giving back to deserving causes. Celiac disease is now close to my heart.

  • Forum Discussions

    The blood test are used for initial screening while the endoscope with biopsy is the gold standard for diagnosis, there...
    Hi, wondering if anyone can help me.   basically I have been tested around 2/3 times for celiac/colitis/Crohns/a...
    It only takes one positive to get a referral to a GI.  You have several positives,  but that does not mean you have mo...
  • Create New...