"May contain" labeling seems like the better solution to this problem. This should be allowed for allergens that are present in the manufacturing or packing facility but not intended to be ingredients in the product.
That's part of the problem. "May contain" doesn't provide legal protection and then if you make it a standard there needs to be testing for compliance which ends up as the same original problem and you just add compliance tits to your food product.
"May contain" should provide legal protection. It may be compliance tits in some cases, but that's better than forcing the addition of a compliance ingredient.
