the fda suggests reading “ may contain milk in dark chocolate . allergens contained in a food product but not named on the label are a leading cause of fda requests for food recalls , and undeclared milk is the most frequently cited allergen . here ’s actually the milk . , an oak ridge institute for science and education fellow , said in an fda shed more light on their testing , findings , and what consumers need to be aware of . “ this can be a problem , since even one small bite of a product containing milk can cause a dangerous reaction in some individuals , ” researcher binaifer bedford , m.s. ” the u.s. food and drug administration looked into dark chocolate , specifically . while milk is allowed as an ingredient , it is not always listed . milk is a permitted ingredient in dark chocolate , but it is also one of eight major food allergens ( substances that can cause reactions that are sometimes dangerous ) . u.s. law requires manufacturers to label food products that are major allergens , as well as food products that contain major allergenic ingredients or proteins .