Food allergies are a fact of life for as many as 12% of all American children. As Dr. James Li of the Mayo Clinic explains, "A true food allergy causes an immune system reaction that affects numerous organs in the body... even a tiny amount of the offending food can cause an immediate, severe reaction." Ninety percent of allergic reactions to food occur in response to the presence of eight items: milk, eggs, peanuts, tree nuts, fish, shellfish, soy, and wheat. Due to the high prevalence of food allergy in the United States, the Food and Drug Administration (FDA) requires processed food manufacturers to list any and all of these eight items, if present, on the labels of the food product in which they are contained.
In its patient guidance regarding food label reading, the Mayo Clinic notes, "Food labeling laws require food allergens to be identified even in very small amounts," but cautions that this applies "only when they're contained as an ingredient." Some food allergens may not be intentionally included as an ingredient in a particular food product, but are contained in that product as a contaminant, due to processing equipment being shared with a food item that does contain that allergen as an ingredient. This is known as "cross contamination."
Although processed food manufacturers often provide some indication that cross contamination may have occurred, this type of label is often unclear, and parents' reactions to such labels vary -- often in hazardous ways. According to a survey whose results were published in a recent issue of the Medical Journal of Australia, parents of children with food allergies behaved very differently about food avoidance, depending on the phrase used on the label. When the label said that the product was "made in the same factory" as a product containing food allergens, 65% of parents surveyed ignored the label and allowed their children to consume the product. However, when the label said that food allergens "may be present" in the product, only 22% of parents surveyed allowed their children to consume the product. Parents of children with a history of anaphylaxis and parents of children with mild to moderate food allergies were equally likely to ignore the label. This points to a need for greater clarity on processed food labels, greater education of parents in the food allergy community, or both.
Some parents may choose to allow their food-allergic children to consume only food labeled as allergen-free. However, even this decision may be based on a false sense of security. A popular test for determining the presence of substances such as food allergens is an enzyme-linked immunosorbent assay (ELISA). However, ELISA may not be sufficient to detect the presence of low levels of food allergens. In research publicized at the February 2013 Food Allergy and Anaphylaxis Meeting, scientists demonstrated that milk, egg, and soy allergens in the concentration of 1000 mg per kg were undetected by ELISA, yet detectable by methods such as mass spectrometry. It appears to be time to revisit the technology used to certify that food is allergen-free.