Seven recalls now trace back to dry milk powder from California Dairies, including chips, trail mix, cheese curds and pizza.

The recalls and warnings stem from a recall of dry powdered milk, which was used in products from popcorn and pork rinds to pizza and chips.

May has been a doozy when it comes to food recalls—and now we have a little more insight into why. At least eight recalls have all been traced back to a single ingredient found in each product: milk ...