8 Tips to Avoid Gluten Cross Contamination

Quote: “These surrogate biomarkers of gluten ingestion indicate that many individuals following a GFD regularly consume sufficient gluten to trigger symptoms and perpetuate intestinal histologic damage.” The is the conclusion of a study published last year in The American Journal of Clinical Nutrition in a paper titled “Determination of gluten consumption in celiac disease patients on a gluten-free diet”.

Though the report studies the amount of gluten that was in the systems of the patients, (via a meta-analysis of 2 clinical programs), the conclusion

shows that nevertheless, inadvertent consumption of gluten (clearly accidental) occurs and negatively impacts especially those who need to avoid contamination the most (coeliac disease-afflicted persons).

So how does one get glutened ‘accidentally’?

Whether you yourself need a gluten free diet; or you are preparing gluten free food for a person or loved one who needs it; or you are a cook or restaurant owner that offers gluten free foods, then read on.

The following article below shares our knowledge and experience on gluten cross contamination and tips on how to avoid it!

Why is Avoiding Gluten Cross Contamination Important?

The answer should be self-explanatory; however, how do you even get gluten in the food when all the ingredients used are certified gluten free?

The answer lies in cross contamination risk – this is the risk that gluten was somehow introduced to the food accidentally, either during the preparation, cooking or serving phase.

Let’s take a look at some of the risks and some simple yet practical suggestions to avoid cross contamination.

Preparation Phase:

Once you are used to preparing gluten free meals and have developed a process, the preparation phase is a non-issue. However, for those early in their gluten free journey, some common mistakes include concurrently preparing 2 meals (say for a busy family at home) whereby you use a knife, your hands etc when preparing normal foods and without knowing, you touch, ever so slightly, the gluten free version.

Let us offer you the following realistic scenario for the home but you can imagine and transpose the scenario to restaurants too. You have to prepare peanut butter sandwiches for the morning run. You have 2 children, one with celiac and the other not. Gluten cross contamination can creep in the following ways:

  • You start with the normal sandwich but forgot to properly wash your hands when making the gluten free version.
  • You used the same knife to spread peanut butter of both the GF and normal sandwich bread.
  • You used separate knives to spread but used the same peanut butter jar – that is, the knife used for normal bread was dipped into the peanut butter jar a couple of times – thereby introducing enough trace gluten levels into that peanut butter jar.

Tip 1: Prepare the GF food first and move on to the normal version. Failing that, ensure that they are being prepared in separate areas.

Tip 2: If you can, get separate peanut butter – we use separate butter dishes ourselves but are careful when taking e.g. peanut butter out of a jar – it’s just an education process.

Tip 3: Before any food preparation, ensure that all surfaces are properly cleaned as any trace amounts of gluten/bread crumbs lying around could contaminate any new foods being prepared.

Cooking Phase:

You have all ingredients that are certified gluten free. However, during the heat (hmm!) of cooking, you may have reached to add some special condiment (without checking the ingredients) or used a wooden spoon that was recently used for normal food (e.g. stirring normal pasta water). Furthermore, wooden spoons are tricky and carry additional risk unless you really wash them well as gluten is notoriously sticky.

You can imagine that this is easier to control in a home setting but if you operate a restaurant, it’s a greater challenge that can be mastered if you follow the tips below.

Tip 4: It is best to put aside all except gluten containing spices/condiments when cooking so nothing accidentally is added to the food.

Tip 5: Use separate cooking implements/utensils. This includes spoons, pans (where feasible) etc. and to avoid doubt, use labels to clearly identify your gluten free utensils. Colour-coding also works well (i.e. green for gluten-free; red for glutenous foods).

One scenario that is common for most homes and restaurant: You only have one oven to bake. What do you do? The Best practice is to get a separate e.g. portable oven. However, most of us (including us) have space/cost constraints.

At the outset, if you bake normal bread in your only oven, we would not recommend to use for GF baking as flour dust may still linger in the oven, especially if you use a fan forced oven. If you use it to bake pies or heat frozen pizzas, you could take some precautionary action:

Tip 6: Bake the GF version of the food first – e.g. GF frozen pizza. If you have have to bake concurrently, put the normal version on the bottom rack and the GF on the top rack. Cover both with aluminium foil. If time and space are not an issue, make them separately or in different ovens.

Serving Phase:

Now that all your foods are well-prepared and cooked without any cross contamination, all you have to do is to serve the food. However, this phase has the highest risk of cross contamination, especially in restaurants! Even at home, if you are not careful, you may introduce cross contamination inadvertently. Typically, this happens by utilising the same serving utensils to serve the foods. For example, say some normal lasagne has touched your hands when plating up, and you thereafter served up the GF without washing your hands, this could easily lead to potential cross contamination in the preparation phase.

However, we wanted to highlight a couple of common examples in restaurants.

1) Café/Restaurants offer gluten free cakes but they are in an open setting. i.e. they are not separately stored/covered from the other cakes.


Tip 7: Mention that you have coeliac disease and that is the reason why you need your food to be gluten-free. With restaurants, you should especially and exhaustively ask about preparation, cooking and serving beforehand. Always express the seriousness of your illness. Ask to see the cook/chef and speak to the manager so that the waiting staff are properly informed and ‘aware’.

2) Gluten free ice cream / sorbet is served with a normal wafer biscuit!


Tip 8: Well, similar to tip 7 but in this case, you have to be vigilant if the ice cream /or food brought back to you is NOT exactly the same sans wafer/bread stick/twirl etc and a new uncontaminated plate/cup has been prepared. In short, the last and best is Be Vigilant!

What Next?

We hope to have started you on your awareness journey on how to avoid cross contamination with gluten at home or outside in restaurants. This would also apply to going for dinner to friends’ houses or parties. The absolute key is to be aware and ask the right questions; and if still in doubt, do not hesitate to ask again and again until you are satisfied. It may seem a nuisance or even embarrassing, but your body and soul will thank you for it!

If you have any questions on the article, please drop us a comment, we’d like to hear from you.