‘Tis the season for showing you remembered to buy something for your loved one, but if the object of your affection is lactose-intolerant, you might want to think twice before splashing out on a deluxe dark chocolate Valentine’s Day gift.

The Food and Drug Administration says after testing 100 dark chocolate products, many contained milk, despite the ingredients listed on a food label.

“This can be a problem, since even one small bite of a product containing milk can cause a dangerous reaction in some individuals,” says researcher Binaifer Bedford, M.S., an Oak Ridge Institute for Science and Education (ORISE) fellow at FDA.

Because milk is one of eight major food allergens, U.S. law requires foods that contain such an ingredient to say so on the label.

It’s not that manufacturers are plotting to sneak in undeclared allergens, as Bedford says they might not even realize it’s in there. Using equipment to make a dark chocolate product that’s also used to make a milk chocolate item could result in traces of milk ending up where it shouldn’t be.

The FDA says it heard from consumers who’d eaten dark chocolate and had harmful reactions, which led to the study testing for undeclared milk. Without naming names, the FDA says the chosen bars come from different parts of the country, and each one is unique in terms of product line and/or manufacturer.

So what should you know?

“First of all, milk-allergic consumers should be aware that a high proportion of the dark chocolates we tested contained milk, even when the label failed to list milk as an ingredient,” Bedford says.

The greatest worry for consumers would be the samples that have nothing whatsoever regarding milk on the label or that have inconsistencies on the label. Like when a chocolate bar labeled “Dairy free” actually contained milk.

Those labeled “dairy free” or “allergen-free” were the least likely to contain milk, however, with two out of 17 samples containing it. And more than half of 93 bars without any clear indication of the presence of milk also were found to contain milk.

If you’re allergic to milk and are concerned, the FDA says you should be aware that a high proportion of tested dark chocolates contained milk.

“And because consumers can’t be sure that a statement about milk is completely accurate, they may want to contact the manufacturer to find out how it controls for allergens such as milk during production,” says Bedford, using information on the label to get in touch.

If you find a product that has undeclared allergens, contact the agency’s consumer complaint coordinator for your state or report food-allergic reactions online to the FDA.

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