Food Contamination Confusion

food contamination
food contamination

Food Contamination Confusion

Are you confused about whether or not non-gluten grains are contaminated with gluten? There has been much controversy whether non-gluten grains become contaminated with gluten. The most controversial grain to date is certainly oats. Oats do not contain gluten, but the prevailing argument is that they are contaminated with gluten and thus, are not recommended as part of a gluten-free diet. Oats contain a legume-like protein called avenalin and a minor protein called avenin. Like the grains that contain the gluten or gliadin protein, which are prolamine proteins, avenin is also a prolamine protein. It is this avenin protein that has been shown to cause a reaction in some celiacs. Other immune markers have also been shown to increase along with intestinal damage in some celiacs exposed to a diet containing oats. (1, 2, 3, 4, 5) But, including oats in a gluten-free diet has also been shown to be safe in others. (6) Even though there are more studies that demonstrate that eating oats may be problematic than studies that prove that they are safe and many nutrition professionals recommend clients to completely stay away from oats, others still recommend to include oats as part of a gluten-free diet. So, what is the best recommendation?

When switching to a gluten-free diet my clients often complain that breakfast is the most difficult meal to navigate as they are used to eating cereal or toast. Knowing that grains are a good source of fiber, many enjoy eating a bowl of oats in the morning. They feel that eating oats would be a welcome addition to their gluten-free diet. So what is to prevent those with celiac disease and gluten sensitivity from eating oats? The primary risk does seem to be contamination with gluten. Several important studies point to gluten contamination in products that are sold in the U.S., Europe, and Canada.  A study published in the European Journal of Gastroenterology and Hepatology in 2007 found that “most of the 109 out of 134 grains and commercial oat products tested were mainly contaminated with mixtures of wheat, barley and rye.” In 2002, a study was funded by the Celiac Sprue Association to assess “whether commercial brands of oats were contaminated with wheat, barley, and rye.” The study was published in the New England Journal of Medicine. The oats tested were from four different lots of Quaker Oats, McCann’s (from Ireland) Steel Cut Oats, and Country Choice Old Fashioned Organic Oats. They were tested using a specialized test for the gluten/gliadin molecule. The oats were purchased at grocery stores several times over a period of 6 months. They were then sent to a lab at the University of Nebraska. The author of the study found the following:

  • Quaker Oats contained from 338 to 1807 ppm (parts per million) gluten/gliadin.
  • McCann’s Steel Cut Irish Oats (processed in an “oats only” facility) contained from below the limit of detection to 725ppm gluten/gliadin.
  • Country Choice Old Fashioned Organic Oats contained from below the limit of detection to 752 ppm gluten/gliadin.  

As you can see, some batches of oats were virtually gluten-free while other batches of the same product contained high levels of gluten.  

It is not difficult to surmise from these studies that not only are commercial oats and oat products contaminated by gluten-containing grains, but also there is great variability in the amounts of gluten in oats. If we were to purchase an oat product we wouldn’t know whether it contained gluten or not. In addition, oats are cross-reactive to gluten. This means that gluten and oats look similar and the immune system can mistake oats for gluten. So, regardless of whether oat products contain gluten, eating oats could cause you some of the same symptoms and health concerns as eating gluten grains.

So, the major question is how did these products get contaminated? And how can cross contamination be addressed?

Cross Contamination can occur in several different ways – from the planting of oat seeds to the final processing of the grain and its placement in containers for sale. Like all grain crops, oats are only grown during certain seasons of the year and most farmers will alternate growing oats with other grain crops such as wheat or barley. Thus, the crops are grown in the same field.  The oats will then be grown in fields with leftover kernels of the other grains. In addition, the harvesting may be done by machines that have already been contaminated. The harvested grain is then placed in trucks that are used to transport gluten-containing grains. At the mill, the processing of the grain will usually be on the same equipment that has processed wheat and other gluten-containing grain products. There is a great likelihood that the equipment is not cleaned between processing schedules. Furthermore, oats can be contaminated by being exposed to the flour dust in the air, which can last up to 24 hours after processing.  Even if the oats are grown by farmers who only grow oats, there is still no guarantee that the oats are not contaminated as kernels can blow into the field from nearby grain farms.  It is easy to see how cross contamination can occur.

Rice, another non-gluten grain is usually thought to be safe to eat.  But, not all rice products are gluten-free.  Again, the problem of contamination comes into play.  As many food manufacturers will include rice based products as part of their staple of food products, they will all be baked or processed on shared equipment with other grains. You might think that a rice product such as “brown rice cakes” would be gluten-free. But, if the manufacturer makes other grain products there is a great likelihood that the rice cakes will be contaminated with gluten.  

In light of the cross contamination, can we be assured that products labeled “gluten-free” are really free of gluten? In January 2009, the European Union adopted the joint guidelines developed by the Codex commission in conjunction with the Food and Agriculture Organization of the United Nations and the World Health Organization, to limit the amount of gluten that can be present in foods labeled “gluten-free.”  The new regulations state that those foods that contain less than 20ppm. will be allowed to use “gluten-free” on the label. In 2013, the FDA followed suit and defined the same gluten-free labeling standards for products here in the United States.

What does this mean for the consumer? What it means is that we have to depend upon the good faith of the food manufacturers to meet those standards. The current outcome is that not all products labeled “gluten-free” may actually be free of gluten. In fact, Whole Foods, a large chain of natural food supermarkets, found that some of its “gluten-free” foods had higher than the recommended safe levels of gluten. (9) The good news is that many manufacturers are using good manufacturing practices and are producing products that comply with even stricter standards than recommended by the FDA. Certain oat and grain growers are operating their own uncontaminated fields and processing plants and are testing their products for contamination using accepted tests and university laboratories.

To further ensure that those with celiac disease choose wisely and safely, the Celiac Sprue Association has set its own guidelines to help those with celiac disease choose the uncontaminated products. They will guarantee products if they meet certain criteria:

  • Gluten-free foods cannot contain wheat (all species), barley, rye, oats (WBRO), all crossbred varieties and derivatives.
  • Use of oats in gluten free foods is not allowed
  • Source ingredients and additives cannot be from WBRO grains.
  • No ingredients “specially processed” to remove gluten are allowed: food starch, vinegar, etc.
  • All products must be risk free at less than 5ppm.
  • Use of ELISA testing to verify and quantify no cross contamination.

It is up to the consumer to practice caution when purchasing gluten-free products.  It is best to choose only those products guaranteed by the Celiac Sprue Association.  You will find a list on their website. (10)

When cooking at home or eating out here are some tips to prevent cross contamination: (11,12)

  • Prepare all gluten-free foods on thoroughly cleaned surfaces. Better yet! Prepare gluten-free foods first.
  • Ask the chef at restaurants to wipe down the grill before preparing your order.
  • Thoroughly clean utensils after preparing gluten-containing foods. Could also have a separate set of utensils.  
  • Clean pots and pans that are used for other gluten-containing foods.
  • Don’t use same toaster for gluten-free and regular bread.
  • Don’t use the same sifter and label the gluten-free sifter.
  • Don’t deep fry in the same oil. French fries at restaurants are often deep fried using the same oil as battered foods that have already been fried.
  • Watch out for crumbs on shared utensils when serving food.
  • Avoid using gluten flours in same kitchen. Flour dust can stay in air for up to 24 hours. It can get into the nostrils, get digested, and absorbed.
  • Order from the menu rather than eating from the buffet at restaurants.
  • Store gluten-free products in tight containers and packages to prevent cross contamination.
  • If using lentils or beans, it is not uncommon to find kernels of wheat or oats in with the lentils. Soak them overnight and clean them thoroughly.
  • Watch out for products in bulk bins, which can become contaminated by using the scoops in more than one bin.
  • Be cautious of eating meat or other protein cooked on a grill that has not been cleaned.

I know that these recommendations seem rigorous, but when you have celiac disease or even gluten sensitivity, even the least bit of contamination can set you back for many months. The key is to be mindful and aware when cooking, cleaning, or eating out.