Alyssa Ramuscak, RD. Celiac Canada Scientific & Research Analyst, January 18, 2026
If you live in a household where some people eat gluten and others do not, the kitchen can sometimes feel like a stress point. You might find yourself wondering, is this counter clean enough? Can I use this cutting board? What about the crumbs I can’t see?
Gluten cross-contamination, when gluten sneaks into gluten-free food through shared surfaces, utensils, appliances, or hands, can be stressful. For people with celiac disease, even the smallest amounts matter. In general, foods with less than 20 parts per million (ppm) of gluten are considered safe, but what does the amount look like in practice?
The truth is most of us don’t have a way to measure gluten at home. We are not testing counters or utensils before every meal or have ready access to a lab to get timely results. Most of the time, it is the daily habits, routines, and best guesses that work to keep food safe. That’s what can make a shared kitchen challenging; not because people aren’t careful and considerate but rather because so much of the gluten cross-contamination risk can feel invisible.
Dietitians and celiac organizations are often great resources to providing guidance on how to prevent gluten cross-contamination. However, research suggests that not all recommendations are supported by strong evidence. Many are based on expert opinion, practical experience, or an abundance of caution.
So how worried do you really need to be? What practices reduce gluten cross-contamination risk?
In a recent Dutch study, researchers examined the risk of gluten cross-contamination across common kitchen appliances including cutting boards (glass, wooden, plastic), toasters and sandwich presses, and deep fryers and air fryers. They also evaluated how effective different cleaning practices were at reducing gluten.
Overall, the researchers found that the risk of cross-contamination depended on both the type of appliance and how it was cleaned. For example, glass cutting boards cleaned in a dishwasher showed the lowest levels of gluten, whereas plastic cutting boards rinsed under cold or warm water posed the highest risk.
When looking at toasters and sandwich presses, the findings were somewhat reassuring. Under normal use and with regular cleaning such as shaking out crumbs, using a toothbrush to remove any sticky crumbs, wiping the inner sides of the toaster with a sponge dipped in warm water and patting it dry with a paper towel, posed low contamination risk. That said, the authors acknowledged that even minimal contamination may still be concerning for highly sensitive individuals. As a result, they continued to recommend using separate toasters for gluten-free and gluten-containing foods as a precaution.
Some of the most interesting findings came from the analysis of deep-fat fryers and air-fryers. Out of 54 samples collected, gluten was detected in one deep-fat fryer and seven air fryers. However, statistical analysis suggested a low probability that gluten levels would exceed clinically relevant thresholds likely to trigger a significant immune response. Importantly, practices such as replacing oil in deep-fat fryers and washing air fryer baskets with soap and warm water were effective in reducing contamination.
With the growing popularity of air fryers as a perceived healthier alternative to traditional deep-frying, these results are particularly timely and important. Air fryers work by circulating hot air and oil around food. Similar to convection ovens, this airflow may increase the chance that gluten particles stick to surfaces and spread to gluten-free foods, if air-fryers are not cleaned properly. This may help explain why some contamination was detected in the tested samples.
The results of the study highlight an important key takeaway: while gluten cross-contamination in shared kitchen appliances cannot be completely eliminated, thoughtful cleaning practices can significantly reduce the likelihood of reaching gluten levels above 20 parts per million, which is the threshold generally considered safe for people with celiac disease.
It is important to recognize the study’s limitation. The research was conducted in a controlled setting at a single point in time and may not fully reflect real-life kitchen routines. For example, when testing the cutting boards, the researchers used a new scouring pad for each cleaning method. In everyday kitchens, sponges, cloths, and hands are reused across tasks. This highlights how gluten cross-contamination can occur at many different touch points throughout food preparation and cleaning.
Living gluten-free in a shared kitchen may likely never feel completely risk free. This research helps shift the conversation around gluten cross-contamination from fear to informed decision making. Using thoughtful cleaning practices and making informed choices can meaningfully reduce gluten exposure. Understanding where evidence is strong, limited, and where recommendations are based on caution rather than data can help people with celiac disease make decisions that protect their health without adding unnecessary stress.
As you think about your own kitchen, focus on creating routines that support both your physical health and peace of mind. If navigating cross-contamination feels overwhelming, consider reaching out to a registered dietitian or joining Celiac Canada’s webinars to find strategies that fit your daily routines and support your overall well-being.
To learn more about the findings discussed in this blog, see:
Burger JPW et al. Gluten contamination in household kitchen appliances: Risks and cleaning solutions. Dietetics. 2025; 4(3):41. https://doi.org/10.3390/dietetics4030041
News, hot topics, tips, education & more.
