I read somewhere that there are 2 bakeries that make GS cookies... one is Little Brownie Bakers and here are the salient parts of their allergy policy (I omitted the self-serving boiler plate that is in every mfr policy):
... Peanuts, tree nuts, egg, cow's milk, wheat, soybean, fish, and shellfish account for 90% of food allergies in the US. These allergen ingredients are required to be labeled on food products when they are present as an ingredient. On our products the side panel provides an allergy box which is located below the ingredient statement. The allergen box clearly states the top 8 allergens contained inside each package....
We do use a may contain statement for peanuts and tree nuts when the product is produced on a line that shares equipment with another product that does contain peanuts or tree nuts. Scientific evidence has shown that consumers with peanut and tree nut allergies can have a severe reaction to amounts that are below the current detectable limits based on existing technology.
Beyond the top eight allergens, all ingredients are declared within the ingredient statement.
