What Is Cross-Contact? (Cross-Contact Meaning)

Food-related cross-contact happens when a food allergen comes into contact with another food, object, or surface that does not purposefully contain the allergen. Because of this, foods and surfaces then may contain trace amounts of the allergen, which are tiny and therefore undetectable amounts. For some food-allergic people, cross-contact with their allergen can cause the same anaphylaxis immune response in their body as ingesting the life-threatening food allergen.

What Is An Example Of Cross-Contact?

One common way cross-contact occurs is via kitchen sponge. If a kitchen sponge in a home setting, or restaurant setting, comes into contact with an allergen such as peanut butter, and then is used to clean utensils or a counter top, it could be depositing trace amounts of peanut protein elsewhere. If the contaminated utensil is used after by someone allergic, or a surface is touched by someone allergic, it can cause a life-threatening reaction via cross-contact.

The Dangers Of Sneaky Cross-Contact

Hundreds of examples of cross-contact come to mind, as I live with a life-threatening peanut allergy daily, and am not only cross-contact reactive to peanuts but also to airborne peanut particles. I’ve learned that being severely allergic to a food, people assume that most settings are safe, and that moving through life being mindful of what I eat is my main focus. Due to cross-contact, that’s not my food allergy experience. Cross-contact is a much larger and difficult part of my food allergy to control because it isn’t confined to eating food and can happen via hundreds of scenarios. I’ll get into some of those different scenarios below:

Cross-Contact Examples In 5 Scenarios

Piggybacking off my earlier blog post on pet related cross-contact, I’ve learned that not only homes and vehicles of friends and family with pets are contaminated, but the entire world is covered in peanut dust, and that isn’t even an exaggeration! There’s just no way to control minuscule amounts of particles and completely remove them from an area.

With that in mind, while I appreciate the gesture that my local Baseball Stadium tries to accommodate those with peanut allergies by having a peanut-free day each year, that accommodation doesn’t work for me. Where I fall on the food allergy spectrum, I don’t feel comfortable taking the risk of attending when I know they serve peanuts every other day of the year! My mind goes to of all the doorknobs, restroom surfaces, water fountain handles, railings, floors, and the surfaces in the food and beverage areas. I would prefer the accommodation that public spaces like this not serve a top allergenic food (peanuts) that the public is disproportionately life-threatening reactive to.

1. Cross-Contact In Food Production

Thinking about cross-contact from a commercial kitchen or food manufacturing standpoint, if the allergens are present in the facility, they’re potentially ending up as trace amounts within the final product. Take a look at my photo of my Trader Joe’s salt below, I was shocked to see soy being a possibility in table salt! This is not a diss to Trader Joe’s, their transparent labeling is great, because people need to be aware of allergens and the risk at the facility level.

Trader Joe’s has a phone line I rely on heavily and am so grateful for (phone number attached below), and it is surprising to learn about the various food allergens packaged on shared equipment as other completely unrelated food items. One coming to mind is that my favorite Trader Joe’s apricot jam is made on shared equipment as anchovies!

In the United States, calling 626-599-3817 will get you through to a Trader Joe’s representative who can tell you what allergens are in the facility and on shared lines with any Trader Joe’s brand product. You’ll just need the barcode! Find other helpful food allergy resources here.

I’ve even seen a bag of kiwis at Kroger labeled “may contain peanuts”. I assumed they were bagged on shared equipment, and was so happy they disclosed that so people can avoid if they’re highly allergic or be sure to wash them extra well, or not purchase them– whatever your comfort level is.

2. Cross-Contact In A Restaurant

There are various levels of food allergy risk when dining out in the United States at a restaurant that isn’t certified allergen-free. At home, I can investigate brands and find out what allergens are in the same facility, and if I can’t, I won’t buy that product However, eating out, I’m unable to know the same information about ingredients, pre-made products, and their corresponding facilities. At home, I email and call on each individual ingredient before ingesting it. However, if I talk to a restaurant chef and afterwards feel comfortable taking the risk, I will occasionally eat out at local restaurants, or commonly known allergy-transparent restaurants such as: Olive Garden, Chipotle, and Taco Bell, where they have the top allergens listed online, and I can verify that there aren’t at least peanut products on the menu and used in the kitchen right then.

When restaurants list food allergy information online like this, it is very helpful to gauge reaction risk level, so that I know the chances are somewhat less, or much more likely. As I mentioned on Invisibly Allergic Blog before, I’ll sometimes eat out when traveling as well, but only after I’ve emailed with them about if they use peanut ingredients (peanut oil, peanut flour peanut butter) or if they would avoid any specific pre-made products they use that they do not make in-house. This is my protocol for myself anytime I eat out in the U.S or abroad.

3. Cross-Contact At Work

Anyplace I work, I ask for no peanut products to be allowed in the building and for HR to enforce this, and to have any snacks with peanuts removed from the vending machines. It’s the simplest and safest way for me to work in a public building. In response to the building being peanut-free, there are typically two main groups of people that emerge: people who still bring peanut ingredients but eat their peanut products outside, and then people who won’t bring any peanut products at all. To the people still bringing peanuts just eating them outside, I do get it, but cross-contact is a major issue for me due to this and I’ll explain why.

Imagine this scenario: a person is eating a small blue bag of planters peanuts a few feet outside the main door of their office building. They begin browsing on their iPhone while eating, and then once they’re done snacking, they wipe their hands on their pants and open the front entrance door handle… See the red flag here?! This happens all the time, honestly, I witness it at least once a week if not more regularly, and that’s just when I happen to be there witnessing it.

The last time this happened, I waited 5 minutes, pacing and debating what to do and if I should cover my hand in my clothing instead of touching it directly before deciding not to contaminate my clothes. I’ve started carrying napkins and wipes with me, but sometimes using wet wipes feels like it makes things even worse since it spreads it all around and I have to use a 2nd and 3rd wipe to wipe my hands of the residue from the first wipe. In this specific instance, the last time this happened, I found a piece of paper on the ground (which honestly could’ve also been contaminated with peanut dust particles, who knows!) and I used it as a barrier between the peanut dust and my bare hand, and walked inside trying to hold my breath as much as possible, and immediately went threw away the paper. However, then, I got to the lobby and elevator where I could assume the person touched the floor number I’m on. So the saga continues in every door, until I can get to my floor and then wash my hands in the bathroom and then use a napkin to open that door for the same reason. If there’s an automatic button to open the door, I love those, and I’ll use my elbow for them since they’re often less trafficked than a regular door handle. I used to use my shoe, in an effort to not touch the button the same way avoid handles, but learned how disrespectful that was to do since others were using the button.

So you see, there’s no getting around allergen particles traveling from hand-to-object (aka cross-contact), and it’s just a part of life I have to be cautious of. And that’s okay, but it’s something I do need to take seriously. I cover cross-contact at work more in-depth in my blog article peanuts at the workplace.

4. Cross-Contact At College

At my college they kept the rooms I was in peanut-less, but the entire campus was not peanut-free. That was fine with me, I brought my own food with me and was appreciative that they created a disability form that I could give to my professors, explaining the no-peanut accommodation in my classrooms. Due to this, I never really had an issue due to cross-contact in classrooms, but I’ll share a story about a peanut reaction I had while giving my -super important- senior presentation, which I had to pass in order to graduate.

I was sitting in a random conference room with 4 other students, presenting to two professors, and the stakes were high. Suddenly, I started to feel my face get really hot and my lips itchy and beginning to swell. I had already presented, thankfully, and was sitting in a leather office chair sitting around an oval table. Before presenting, I’m sure I was nervously going over my presentation in my head, touching my face, and maybe even biting my nails. I looked down in the back of my seat to check my surroundings and try to reassure myself it was probably nothing, and it looked as if someone had eaten peanuts in my chair! There were a few actual whole peanut pieces around the back crease of the seat.

In shock, I hesitantly interrupted another student presenting, to let them know I needed to leave immediately because of my chair and that I was having a peanut reaction. They were equally as shocked and horrified. It was absolutely not intentional, as I was a part of the discussion when we randomly chose the office, and I even chose my own seat. I was so nervous I probably didn’t even pay attention to my chair like I normally would, and so it was a complete fluke, and something I now am on the lookout for in shared spaces. Luckily, I was swiftly able to get home safely to take medication and be monitored by my husband. He was ready to take me to the ER if I needed it, but thankfully it must’ve not been as much peanut cross-contact as it could’ve been, and I was back to normal within 24 hours.

5. Cross-Contact From Friends

Essentially, all spaces besides my home are fairly likely to be peanut-dust contaminated. Even inside my own home and car, cross-contact can spread and cause me to have a reaction, so there’s no 100% guarantee anyplace. With friends and family, it can be especially tricky, since they may be aware of peanuts when they’re around me but eat them on their own time when I’m not around.

One time, I was inside a friend’s car who warned me they had recently eaten peanut products in there, potentially wiping their hands on the seat or shared spaces as the passenger’s side. She wiped the car down before I got in, but I was still very happy she shared this information with me, so I knew to be extra sure to not touch my face, and know to shower once home, wipe down my phone, and put my clothes directly into the laundry. Another friend once lost a peanut in her car for over a week, and she would not let me in it until she found it.

Once on Christmas Eve I was eating dinner with my in-laws who are very aware of my allergy, but they hadn’t considered how they were snacking on mixed nuts when putting dishes away and preparing one part of the meal. I ended up having a bad reaction, landing me in the ER on a holiday, and it was an unfortunate experience that reminded us all,, myself included, why I have to take my allergy more seriously. Now, I typically bring my own food from home, and will hand-wash dishes before using them. Even bringing my own sponge or kitchen towel aren’t out of the question!

When it comes to my food allergy, I appreciate being in-the-know about anything peanut-related, because as you can tell, it may impact me. Cross-contact is not to be handled lightly, and depending on where you fall on the food allergy spectrum, it could unfortunately lead to a life-threatening reaction.

Food Allergen Particles Linger For A Long Time

With COVID so fresh in all of our minds, I’ve thought time and time again how convenient it would be if allergen particles could be killed or destroyed with alcohol or bleach. Instead, food particles tend to really linger and can contaminate surfaces indefinitely. For example, say I sat on a public park bench where someone unbeknownst to me was shelling peanuts an hour before I got there and sat down. I could walk back to work, sit in my office chair, contaminating that surface without realizing it, and then hours later, I could put something in my back pocket, touching the pants covered in peanut dust, and then touch my face, igniting a life-threatening allergic reaction. The trace amounts are hard to trace! Often, I don’t know why I’m reacting, and can’t pinpoint it, but I have to take it seriously and trust that it is due to cross-contact not able to be seen.

Final Note: An Eye-Opening Cross-Contact Statistic

To reiterate, being allergic to the dust and trace particles of my allergen, when they’re too tiny to be seen with the naked eye, is the trickiest part of my peanut allergy. Deadly particles are quite literally almost everywhere and they spread extremely easily, and we have no way of knowing if they’re there. I’ve learned that moving through life it is easy to become contaminated, and you’d never notice these allergen particles unless you needed to, or until it’s brought to your attention.

I’ll leave you with one eye-opening statistic I learned recently– each peanut kernel contains about 300mg of peanut protein, and research has found it has taken only 1mg to put someone into deadly anaphylaxis. Meaning, each peanut contains 300x the amount of the allergen known to have sent someone into a life-threatening reaction.

Cross-Contact Additional Resources

• Learn the basics concerning food allergy facts, stats, what to do in the event of an allergic reaction, and many cross-contact examples in my free PDF on food allergies and cross-contact 101
  • This is a free PowerPoint presentation & audio file. You’re welcome to share this with your workplace, family, or anyone else.
• Check out my similar blog article on Cross-Contact vs. Cross-Contamination where I explain and compare the two similar but different terms!
• Food Allergy Research and Education (FARE)’s cross-contact and cross-contamination article with many resources and FAQs

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