The Food and Drug Administration (FDA), Washington, D.C., announced plans to begin enforcing the agency’s definition of milk, which references products that come from animals that lactate, posing a potential marketing challenge for makers of plant-based beverages.

Likewise, nearly 46% of U.S. adults say the label “milk” should not be used to describe non-dairy beverages, according to a poll conducted by Morning Consult, Washington, D.C., and Politico, Arlington County, Va. The poll surveyed 2,203 adults from July 19-23, with a margin of error of 2 percentage points.

Adults age 65 and older showed the strongest support for the FDA’s potential label enforcement (66%). Young adults, ages 18-29, showed the strongest support for allowing non-dairy beverage makers to call their products “milk,” at 39%.