Processed food gets a bad rap sometimes, but in reality, most food you eat is processed to some extent. A package of apple slices bought at a supermarket might seem like a good non-processed snack, but the very act of cutting the apple into slices is itself a form of processing.
Many processed foods obviously go through more processing than just slicing, and as they are processed, they could be exposed to minute amounts of other foods that aren't supposed to be in there. For example, potato crisps may be sliced on equipment in a facility that also slices bread that contains gluten and eggs or dairy, which are among the most common food allergens. Residue from the bread in the form of tiny crumbs could be picked up by airflow from a ventilation system, for example, thus contaminating the potatoes as they emerge from the fryer.
This is called cross-contamination. It's not limited to just food allergens, but it is a problem in food processing due both to mechanical and human error. If your facility produces food that is sold for human consumption, you need a way to test for potential cross-contamination of allergens.
Why Is Cross-Contamination a Problem?
Reactions to food allergies vary greatly. Someone who is very mildly allergic to dairy might not react to that minute amount of crumby contamination on those potato chips. Yet, someone with an intense allergy to dairy actually could have a reaction.
Chances are that when someone picks up a pack of food that has been processed in a facility that follows food safety procedures, they aren't going to encounter the allergen. But mistakes can happen, which is why you sometimes see notices about recalls for unlabelled allergens. It's not that the facility was careless; it's that somewhere along the line, there was an unintended mistake. Unfortunately, that mistake can harm people.
Tracking Down the Source of the Problem
If consumers report an allergic reaction, testing can help you find the source of the problem. Let's say you produce seasoned potato crisps that are labelled as being free from dairy products. A consumer eats them, along with other products labelled as free from dairy, yet the consumer has a reaction. Testing can show that your facility is not the one that produced the contamination. Or, the test can show that the contamination was not from the potato equipment but from the seasoning mix, and you can track the contamination back to what happened when the mix was created.
Allergen testing should also be done when you change ingredients and recipes. It does not take long and can save your facility a lot of heartbreak and work in the meantime.