Cross-Contact or Cross-Contamination: What’s the Difference?

I’ll be honest with you: distinguishing between cross-contact and cross-contamination used to throw me off. Many people in the food allergy community (my past-self included) often mistakenly use the terms interchangeably.  

The confusion is so widespread that even food manufacturers and allergists mix up the two. In fairness, cross-contact is a new(ish) term, so some have gotten into the habit of labeling everything involving inadvertent food exposure as cross-contamination. “I’ll be the first to admit that I don’t always use the terms correctly,” says allergist Dr. Jordan Scott. “Many of us were trained to use cross-contamination to refer to allergens inadvertently getting into another food source.”

To help clear up some of the confusion, we’re breaking down the difference between the two terms in this post.

Let’s start with some examples.

Cross-contact:

This occurs when a food allergen in one food (let’s say milk protein in cheese) touches another food (let’s say a hamburger), and their proteins mix, transferring the allergen from one food to another. These amounts are often so small that they can’t be seen!

In this example, let’s assume I have a severe milk allergy. If the cheese touches the burger, cross-contact has occurred. Even if the cheese is removed from the burger, trace amounts of the milk allergen likely remain on the burger making it unsafe to eat and posing the risk of an allergic reaction.

It’s important to note that most food proteins (with few exceptions, like heat labile proteins) CANNOT be cooked out of foods, no matter how high the temperature. When our daughter underwent oral immunotherapy for her peanut allergy, we were given the option to bake the peanut flour into muffins for her to consume. We were told that the high oven temperature would not affect the protein structure of the peanut flour.

Cross-contamination:

Cross-contamination occurs when a bacteria or virus is unintentionally transferred from one food product to another, making the food unsafe. The key mark of distinction is that cross-contamination generally refers to food contamination, not food allergens.

A couple of examples: you cut raw chicken on a cutting board before you put it on the grill. You then cut peppers on that same cutting board. The raw chicken juice touches the peppers, therefore posing a risk for bacteria. Or say you purchase a cantaloupe that unknowingly has listeria. The knife used to dice up the melon is now a vehicle for cross-contamination. Unlike cross-contact, properly cooking contaminated foods generally CAN eliminate the food-borne offender.

Is it all making sense now? In short, when referring to food allergens, use cross-contact, and when referring to food-borne bacteria or viruses, use cross-contamination. Easy peasy.

Want to discuss this topic further? Still confused? Feel free to reach out to me at mnohe@allergyamulet.com. I’m always game for a good food allergy chat!  :)

— Meg and the Allergy Amulet Team