This is easily one of the greatest struggles when living with a food allergy. Whilst it’s also a struggle with those who have a special diet or food intolerance, the consequences for the latter groups is less lethal.
First, we need to officially define cross-contact and cross-contamination. In the food (service) safety world, cross-contamination refers to pathogens, bacteria, and food borne illnesses. Example: a chef places raw chicken on a cutting board to prep it for service. After completion, raw celery which will be served raw is placed on the same cutting board. There’s contamination from the raw chicken and can cause a food borne illness.
Cross-contact (in the food service world) refers to allergens specifically. If a chef uses a spoon in the sauce containing dairy, then transfers the spoon to the dairy free sauce. In this case, a pathogen was not transferred because the sauce is cooked. However, depending on how you look at this example, cross-contact IS cross-contamination for many. In other words, a food borne illness still happens. Hope that makes sense.
Just know that if you’re talking to a food service worker and ask about “wheat cross contamination” they may not understand what you’re really asking about. Also know that when you talk to other food allergy folks, when they say “cross contamination” they’re usually referring to “cross contact”.
The Usual Suspects of Cross Contamination/Contact
There are so many places where allergens can hide and cause issues for those with food allergies. Here are the top 5 locations cross contamination happen:
- Shared Manufacturing Equipment
- Bulk Bins at Grocery Stores
- Non-Stick Cookware
- Shared Cutting Boards
The list of cross contamination pitfalls is a lot longer, and there are loads of resources on RAISE to help you navigate. However, for the sake of not writing a 20-page essay, I’ll stop myself there. I don’t say ANY of this to scare you. Rather, I want to empower and educate.
I feel it’s so important that we walk into this whole “lifestyle” eyes wide open so we’re better able to serve ourselves and our children.
Let’s Investigate Those Suspects
Did you know most dairy free food is made on shared equipment with dairy? Lots of certified gluten free foods are made on shared equipment with wheat… let those facts sink in for a moment. Read more about this in the Dairy Free Swaps article and then take some time to Learn How To Call Companies About Food Products.
For some people, this won’t be an issue. Trace amounts of allergens don’t pose a threat and they’ll be a-OK to consume said foods. For others however, they will have to be vigilant and ensure that their food is produced on dedicated equipment, or in a dedicated facility. The only way to learn this information is to get in touch with the company that produces the food.
If you hear things like “We have an allergen program in place and test” still push the question. Get definitive answers and make sure the food is safe for you. Ask about recalls and how often the tests fail. Any company that can’t be transparent with you should not be trusted (assuming you can’t have trace amounts). If you’re new to the allergy world and the thought of calling companies is completely overwhelming, check out the Safe Product Guides/Lists on RAISE to get you started. We called thousands of companies to find out which are providing safe food.
Bulk Bins at the Grocery Store: A Cross Contamination/Contact Nightmare
These can pose a problem because as customers shop, there’s residue on their hands. Their hands touch the handles to scoop food, and in some cases, the handle may touch the food. Customers may accidentally touch the food, or drop something into the bin. They may scoop from one bin, then leave trace amounts in the next bin they access.
I have personally witnessed this and can’t stress this enough: if you can’t handle trace amounts, avoid the bulk bins. You can usually ask the store to special order something in bulk, or contact the manufacturer directly.
Non-Stick Pans Remember Food Allergens
“Non-Stick Remembers” is one of the best things I can tell people. If you’re new to food allergies, old non-stick pans should be replaced. Same goes for cast iron, and anything that has scratches. Allergens can remain in the crevices and cause a problem later on. Total side note, but not: shared toasters are not gluten free.
On to Sponges, A Place Where Allergens Hide
Picture this, you’ve made cheese pasta in a pan, and are cleaning it off with a sponge. Next, you grab the pan used for your allergy kid and clean it too. Same sponge of course. There it is… the dreaded cross contact. In our home we have four sponge stations for this exact reason… to prevent contact whilst cleaning up.
Each sponge is a different brand/colour and the sponge holders are different. When the kids were younger, the holders were labeled as well.
Shared Cutting Boards Are a Problem for the Same Reason as Scratched Items
Knives create small crevices in your cutting boards for allergens to remain. I knew a guy once who cut corn-contaminated watermelon on his cutting board, then had a full-on allergic reaction the next time he used the board (after it had been washed). Sadly, it was like a two-for-one reaction in that case. Needless to say, when I try new produce for myself (as someone living with a corn allergy), I cut on a safe paper towel before I trust to use my personal cutting board.
Whilst there are lots of other ways cross contact can sneak into your kitchen, these are the top 5 by far. I will add in one more however: people.
People will always be the weak link, and it’s almost always an accident (yes, some people are seriously malicious). It’s an accidental double dip, or grabbing the wrong pan. It’s eating an allergen and forgetting to wash up before moving on (especially hard with little kids).
Allergens are everywhere, and the more we can learn to avoid them, the safer we will be.
Often Overlooked Sources of Cross Contact/Contamination at Home
Pizza stones and pizza ovens are super fun to use, but difficult to clean. If you’re a fan of pizza making, and you’re a mixed allergy household (especially gluten free, wheat free, dairy free, corn free), make sure you have two units.
We ended up spending a LOT of money on our pizza oven, knowing we’d purchase a second one eventually. After it was all said and done, we decided to bypass purchasing a second unit and opted to have everyone eat the same safe pizza.
Whilst this decision limits flavour choices, it’s saved us a lot of money. Plus, in my case, I told those who were in favor of a second unit they were on their own to make the pizza and suddenly, they were fine with the free-from versions I was making 😂😂
Air Fryers are also very popular right now, and an overlooked source of cross contact/contamination. In our home, specific allergens are never in the air fryer, though truth be told, we don’t use it often. Turns out I don’t like it (or we got a bad one).
Plastic blender containers, specifically those that aren’t dishwasher safe. A good example of this is Vitamix. RESIDUE IS TOTALLY THERE. Here’s what I want you to do: make something in your Vitamix that contains oil or a nut/seed spread. Then, wash it the way Vitamix tells you to. Guess what you have: a clean-dirty-contaminated Vitamix.
When we purchased our first one, even though it clearly said not to put it in the dishwasher, I did it anyways. I saw the potential for cross contact and was being proactive. Guess what happened? It broke the Vitamix.
I called them, and the lady asks about the dishwasher. I say yes and tell her why. She was super sympathetic to the situation but confirmed there’s a reason you don’t put the container in the dishwasher. They were kind enough to replace the container and extend a discount on a second container purchase.
Fast forward years later when we got a new Vitamix… I purchased 2 additional containers on day one. Vitamix now sells a metal container that’s dishwasher safe that might be a good option for some of you.
How We Prevent Cross (Contact) Contamination Of Allergens In Our Home
These are the main steps that we take to prevent issues. For more details, RAISE has a walkthru of our kitchen(s) These steps are mainly for our child with life threatening food allergies (my personal protocols are a bit different, and we’ll have to cover those another day).
- Purchased packaged foods must be made on dedicated equipment, free from dairy and wheat. He is egg intolerant, so we allow shared equipment with egg.
- Companies must be called before a commitment to multiple purchases. Sometimes he takes a bite (for product reviews) but until we hear back, it’s generally a no-go.
- Food is cooked at home in dedicated pots/pans that are color-coded.
- Wooden spoons are color-coded, as are items such as colanders.
- Multiple (labeled) versions of some tools, ex: Vitamix containers, ice cream machines.
- Major allergens are kept outside the kitchen in a separate fridge.
- We have two toaster ovens and an outdoor hot plate.
- Major allergens must be eaten with disposable utensils and plates/bowls.
- There is a separate trash can in the front room for major allergens so they don’t enter the kitchen.
- The sink must be clear before major allergen dishes may enter (pots, etc.)
- Separate sponges for allergen foods.
- Hands must be washed (even if you think nothing touched you) after handling allergens.
- Allergens are eaten at a small table, separate from the main dining table. UPDATE: We have a pretty big dining table now and a whole section has been marked off for Kid Two. Since the kids are much older and messes aren’t too bad, everyone is at the main table and allergens don’t go into the marked off space.
Top Questions on Cross Contact and Cross Contamination Answered
Before I answer the questions, first I want you to watch the video on this post about cross contact. I SHOW YOU what it can look like in a home and even commercial setting. This cross contamination example is one of my faves because it’s happening in homes everyday.
Often times, people think it’s OK to share equipment or a facility. When you watch the video you’ll quickly understand how EASY it is to transfer allergens from one place to the next.
What does gluten contamination feel like? (Symptoms of cross contamination)
This will be unique to you. For most people who need to avoid gluten, when there’s been cross contamination/contact, they say “they’ve been glutened”. It means they have the symptoms they normally experience when eating gluten.
For some people, the symptoms are mild (compared to if they had eaten normal serving), especially when compared to their life pre-diagnosis. For others, it’s catastrophic. We know one person who was in the ER then had to stay in hospital for weeks from TRACE AMOUNTS of gluten.
Your reaction will be unique to you, but this also highlights why it’s so important to take elimination and avoidance so seriously.
Can allergies be cross contaminated?
Yes, but remember, in the food service industry, they use the term “cross contact” to describe what most people with food allergies call “cross contamination”. By food service definitions, technically, no, it’s cross contact, not contamination. Yet, as I explained earlier, the cross over still causes illness, therefore, can’t we still call it contamination?
Just be sure to use the correct terminology if you’re trying to eat out at a restaurant, and explain that you can’t have trace amounts of allergens.
Can gluten be cross contaminated?
Yes, like major and less-common allergens, gluten can be a source of cross contamination/contact. It’s the same process. If a gluten-containing ingredient was involved, then the cross contact can happen.
In the case of gluten, it can also happen via air transfer when flour is involved. See this video for an example.
How do you avoid cross contact with gluten?
Read the advice I share about what we do in our home (scroll back up a bit). These are steps you can take. However, with gluten, flour is involved and it’s a lot harder to control.
The easiest way to avoid cross contact with gluten is to never bring it into the home. If that’s not an option, don’t bring wheat flour into the home and use a gluten free flour instead. All pre-made gluten containing ingredients should be stored and consumed outside the kitchen. In our home, wheat flour never comes thru the door, as it can be a nightmare. Premade items containing wheat however are allowed, but aren’t eaten in Kid Two’s safe areas.
Now, if we’re talking restaurants, that’s a whole different story. Honestly, the easiest thing to do is to find a dedicated gluten free restaurant. Almost any location that bakes on site has no way to guarantee your safety. We found one… once. They built a special basement baking room so the flour never entered the main kitchen.
How serious is gluten contamination?
This will be an individually answered question. For some, it’s a few hours of minor discomfort. For others, it’s hours vomiting. In rare cases, it’s a trip to the ER. Your individual level of tolerance and symptoms will dictate the seriousness for you.
If you are managing a child, please always assume the worst can happen and take avoidance very seriously.
Also know that if you’re managing a wheat allergy (which is not the same as gluten free), then you’ll need to know that in people who can’t handle trace amounts, cross contamination can lead to anaphylaxis. This is life threatening.
Does a dishwasher get rid of gluten?
Yes and no. Let me tell you a story. I was at a food event once and we weren’t allowed to wash our own dishes. They had to be handed off to a specific person and they were put through a commercial dishwasher. The point of a commercial dishwasher is to kill pathogens and sanitize.
When our dishes were returned, food particles were still on the dishes. See my point?
The removal of the allergen needs to happen before the item enters the dishwasher for best results.
Can gluten be washed off dishes?
A better way to say this is “traces of gluten can be removed from dishes”. We wash off dirt. We remove allergens and gluten.
I want you to think about glitter, as it’s the best way to describe allergens. You can cover a plate in glitter and run it under water and some glitter will remain. We must REMOVE the glitter. It’s the same with food.
Gluten cross contamination in a deep fryer?
I’m glad that this issue has received more attention in recent years. Gluten and allergens can ABSOLUTELY be transferred via a deep fryer. The oil is saturated in small particles of allergens and gluten. If you put something that’s “free-from” in that fryer, you cannot avoid cross contamination/contact.
The only way to prevent this is to have a dedicated gluten free fryer (even better if it has a lid).
Which cleaning product is required to stop cross contact of allergen foods?
Cleaning to remove food allergens seems straightforward, but let’s go back to the glitter example. There isn’t a magic product for removal. It’s a physical action. The same is true of allergens and gluten.
To eliminate the allergen completely, it must be wiped off/removed. Do some products denature the protein? Sure. However, we know that in some individuals, even without the protein present, a reaction can still occur.
So it’s not about WHAT you clean with but HOW you do the cleaning.
Can allergen cross contamination happen through cooking oil?
Yes! Just like the gluten and a deep fryer question, the same is true of major and less common allergens. Remember the glitter example. If allergens are glitter and you coat a potato in it, fry it, then remove it, some glitter will fall off in the fryer and remain. The next item to go in the fryer can pick up pieces of glitter.
The only way to ensure this doesn’t happen is to have separate fryers/cooking pots.
How do you destroy most food allergens?
Denaturing the protein is the way most people agree upon. In the case of an oven, you need a temperature of 550f+ for at least 10 minutes. However, we know that it isn’t always about denaturing the protein for some people.
Rather than think about the word destroy, I want you to think of the word remove. We need to REMOVE the allergens. Wiping away is the easiest way to remove allergens from a surface. However, think glitter. We want to wipe it away, not smear it all around.
Here’s something to think about when cleaning, and wondering if you’ve done a good job. Let’s say you had milk all over a counter, then work to remove it. Have you cleaned up well enough for someone allergic to milk to eat directly off the counter? Is all the glitter gone?
How long do food allergens stay on surfaces?
Brace yourselves. Forever, or until it’s been removed. Think about a bakery. They go in on Friday morning and use several bags of flour. Particles of wheat flour and gluten are in the air and eventually settle on surfaces and other equipment. The bake team leaves for the weekend.
Whilst they’re gone, nothing happens in the bakery. These particles don’t magically disappear. Unless someone goes through to remove them, they will remain. Forever.
This is the same with anything you’re allergic to. If the allergen is not removed either naturally by nature (think wind through our bakery for some odd reason) or by physical removal (cleaning) the allergen remains on the surface.
Whilst proteins can denature over time, if we’ve learned nothing else today, it’s that this isn’t enough for some people. Removal is key.
I think those are all of our steps. Part of the reason it works: the kids have been trained their whole lives. For people with older kids who are newly diagnosed, there will be a (tough) time of transition. Remember to stay proactive and positive during any major change in your home. For as hard as this is for us parents, it’s hard on the kids too. If this is all seems completely overwhelming, you’re not alone. We’re here to help with 1-on-1 consultations to get you started and answer your questions directly.
- Food Allergy Help 101 Course (free to enroll)
- IG Story Replay: Cross Contamination Visual
- RAISE Podcast Episode 15: Grocery Store Cross Contamination
- Expert Roundtable: Food Manufacturers
- Reading Food Labels: Living With Food Allergies
- Hidden Sources of Gluten & Wheat
- Allergy Seminar Replay: Food Allergy Tips