Federal regulators have upgraded a product recall of Lay's Classic Potato Chips to the highest risk level for a batch that may contain undeclared milk ingredients. Last month, Frito-Lay issued a recall warning that more than 6,

Frito Lay issued the recall in December after it was found that there was a potential or undeclared allergen, specifically milk, in the chips.

The FDA has upgraded a recall of Lay’s Potato Chips to the highest level possible, meaning consuming the chips will cause adverse health consequences. In December, Texas-based food manufacturer Frito Lay recalled a limited number of Lay’s Classic 13oz because the product could contain undeclared milk ingredients.