Warning: Hidden allergens in food

Today's Tribune notes the prevalence of unlabelled allergens in food:

Eight foods—milk, eggs, wheat, soy, peanuts, tree nuts, fish and shellfish—account for 90 percent of food allergies. That's why federal law requires ingredient labels to disclose them....
The newspaper also found more than a dozen products with incomplete labels that, for example, simply list "flour" as an ingredient. If an item contains, say, wheat flour, the packaging must say so.

Likewise, if a label discloses "butter," it must also state "milk." The law was written that way partly because many children with allergies must check labels themselves and cannot be expected to know the sub-ingredients in foods.