Gluten Cross Contamination – How much do you really need to worry about it?

What is Cross contamination?

Cross contamination is when Gluten free food comes into direct or indirect contact with gluten containing foods or utensils in the preparation or handling of food. This would then involve ingesting the gluten that has cross contaminated your food.

How much gluten is enough to cause intestinal damage?

Research and studies have shown that in order for something to be termed “gluten free” it should not contain more than 20ppm of gluten (ppm stands for parts per million). Further studies [1] have shown that anything from 10mg to 50mg of gluten on a daily basis is enough to cause intestinal damage. Since the average person doesn’t have the tools to measure how much gluten is in each product they are consuming, What would this be the equivalent to? the answer is :10mg is the amount of gluten in a 350th piece of a slice of bread [2] which is really basically crumbs! So when a person with Celiac disease says “Even a crumb will affect me” they are not exaggerating!

How can I avoid cross contamination?

While it would be impossible to list every source where possible cross contamination could occur, the following is a list that offers some direction for home use.

  • Sharing Utensils and preparation surfaces while preparing between gluten and non-gluten foods. Such as using the same knife to slice breads or spread butter.
  • Bread boards: It is better for a person with CD to have their own breadboard as shown above, in the tiniest amount is enough to cause intestinal damage, and gluten can hide in the cracks of bread boards.
  • Store gluten free food in their own containers whether in the fridge or in the pantry.
  • Studies have shown that Consuming fries that were cooked in a fryer in which gluten food was prepared has been shown to contain high amounts of gluten.[3]
  • Prepare and cook glutenfree food separately. This will greatly reduce the risk of cross contamination.
  • If you own a dishwasher, it is better to wash as much as will allow in the dishwasher. Otherwise, use hot soapy water and wash thoroughly as well as rinse.

What about a separate Toaster?

A study was done in which gluten bread and then gluten free bread was toasted in the same toaster in a busy hospital cafeteria at 20 minute intervals without being cleaned between the different types of bread. The study result that toasting in a shared toaster was not associated with gluten transfer (which needs to be greater than 20 ppm) the 3 samples with detectable gluten had levels ranging only from 5.1 ppm to 8.3 ppm gluten. [4] This study makes it appear that It seems unlikely that sharing a toaster can cause cross contamination. However, it is possible that more in depth studies need to be done as indicated by some good points that the glutenfree watchdog mentioned on her post.[5] Each person should make their own call.

What are the takeaways?

Research and studies regarding Celiac disease and things like cross contamination are ongoing. However, there is a lot that remains unclear for the average person. This also explains why it would seem some people are hyper vigilant when it comes to Celiac Disease. What is good to keep in mind that Celiac Disease is an auto immune disease. It does not take much gluten for the body to attack itself and in doing so, to damage the villi of the intestinal walls. The amount of gluten that causes damage also varies from person to person and some react to the slightest amount while others seem not to show any visible symptoms (this however, does not mean no damage has taken place).

Note: I am not qualified in medicine or nutrition.As a person with Celiac Disease my aim is to try inform, educate, and offer advice but also to try and remember that no two people with Celiac Disease will have the same experience, symptoms or reactions. I speak from my personal experience only in the aim of helping others. As always, consult the relevant healthcare practitioner regarding any health related issues/supplements/treatment. Please read my disclaimer on my blog should you want more information.


Citation 1 : Rambam Maimonides Medical Journal

Citation 2: National Celiac Association

Citation 3: Frontiers in Nutrition

Citation 4: Gastro Journal

Citation 5: The Glutenfree watchdog

Published by Bonnie

Hello. My name is Bonnie. Welcome to my page. I have been an avid baker for about 20 years. Of those years, seven have been gluten-free baking. I discovered I had a chronic intolerance to gluten and began experimenting with converting my all time favorite recipes into gluten-free ones. I also have developed my own recipe repertoire. I am married and have two children. My husband and son are not gluten intolerant but my daughter is. She has also been the motivation for persevering in creating recipes we both can enjoy. My journey has taught me so much and I know many others can benefit from my experience. My hope is that you will find something you can order that you have missed and longed for being gluten intolerant or celiac. Or perhaps you just want a healthier option as I also offer alternatives to some of my orders such as sugar free, grain free and low carb. I share my experience and story in more detail on my Instagram page. (@bonniesGFbakery) Please feel free to follow me there. Located in Somerset West, Western cape, South Africa. I deliver to the Helderberg basin area which includes Somerset West, Gordans Bay and Strand.

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