Cross-Contamination | Allergy


by Allergy Guy

Cross-contamination is a serious issue for people with allergies.  An allergen may not be intentionally added to your food, but it could get there by mistake.  This article highlights the cross-contamination issue, what to watch for, and how to avoid it.

Cross-contamination, as far as food allergies is concerned,  is when the food you are allergic to accidentally and unintentionally gets added to your dish.  Depending on how sensitive you are to a particular food, this can be a serious problem that you have to watch out for.

If you have a gluten allergy, peanut allergy, shellfish allergy, or any other allergy to which you are sensitive and have a strong reaction to, then you have to watch out for cross-contamination.  The more sensitive you are, the more you have to worry about it.

I used to worry about cross-contamination for my gluten allergy much less than I do now.  I found that the more I avoid gluten, the better I feel, so I now watch out for the tiniest amounts.  On the other hand, small amounts won’t bring me down, they just make me feel a bit less than 100%.  For others though, especially for those with an anaphylactic shock reaction, it is essential that you understand cross-contamination and allergies and how to avoid it.

Cross-Contamination – How it Happens

Cross-contamination can happen in a number of ways.  It can happen in the kitchen, for example crumbs on the counter, or using the same spoon to stir gluten-containing and gluten-free foods.  It can happen with food handling equipment at a packaging plant.  It can even happen in the dishwasher.

It is impossible to list every possible instance of cross-contamination, but here are some examples to get you thinking:

  • Gluten allergy: someone uses a knife to spread butter on their bread, then uses the same knife to get more butter, adding crumbs to the butter.
  • Peanut allergy: a knife used for peanut butter goes into the dishwasher, and comes out with a speck of peanut butter on it.  That speck is too much for some people.
  • Shellfish allergy: a cutting board is used to cut shellfish, then used to cut vegetables destined for a fish-free dish.
  • Gluten allergy: the equipment is used to fill bags of wheat flour, then the same equipment is used to fill bags of rice flour.

For more ideas specific to gluten allergy, see Gluten Free Diet and Cross-Contamination of Food.

Avoiding Cross-Contamination

To avoid cross-contamination, you must be vigilant, and only buy from trusted sources.

Watch out for how other people store, prepare and eat the foods you are allergic to, and make sure your food doesn’t come into contact with their methods.  If you can, try to change their methods.  My household is completely gluten-free, which is a big help for me, but when I go to the cottage, I have specially marked jam, butter etc. that no one else uses.

It is worth the extra money to buy specially packaged and labeled foods that do not contain the foods you are allergic to, unless you don’t react much to small amounts.

Explain your allergies and cross-contamination to everyone who shared or prepares your food.  This is tedious but necessary to avoid getting sick.


Do take care of yourself but don’t become paranoid.  The extra stress will probably make you less effective and ruin your life.   If you have a life-threatening allergy, then yes, you have to be very careful, and banning peanut butter entirely from a school for example, may be what’s required to keep people, and especially children, safe.

What are your experiences with cross-contamination and allergies?  Share your questions, comments and advice, leave a comment below.

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