Al Overland is not saying you should refer to almond milk as nut juice. He's also not saying you shouldn't.

"I've heard it called that," said Overland, a dairy farmer near Sturgeon Lake, Minn. "They can call it juice or beverage, or whatever they wish, but we just don't want them to call it milk."

Dairy farmers, who are struggling with widespread industry consolidation, low prices and declining demand, are becoming even more fed up with all the nondairy products in the grocery store labeled as milk.

The number of different types of "milk" available to consumers has ballooned in recent years. First it was soy, then almond milk, coconut milk and rice milk. Now, there's oat milk and pea milk.

The Food and Drug Administration is mulling whether to update its rules for how to label plant-based foods, and has been lobbied hard by both dairy and plant-based producers. A four-month public comment period closed at the end of January, and 8,624 comments were submitted.

Dairy groups say the FDA has allowed an "anything goes mentality in the marketplace." Plant-based groups say the objections are much ado about nothing and would disrupt the marketplace.

A debate raging among dairy industry representatives, federal regulators, makers of “alternative milks” and consumers all boils down to the question: What is milk?

"This entire exercise is a solution in search of a problem," said Michele Simon, executive director of the Plant Based Food Association. "At a time when resources are scarce, our federal government should not be concerned with how 'almond milk' is labeled. Aren't there higher priorities, such as the safety of our food supply, for FDA to worry about?"

According to the federal "standards of identity" regulations, milk is "the lacteal secretion, practically free from colostrum, obtained by the complete milking of one or more healthy cows."

Lucas Sjostrom, executive director of the Minnesota Milk Producers Association, said the federal regulations should be enforced. And the dairy industry, he added, is fine with lacteal secretions from other types of animals being labeled as milk.

"We have no problem with goats," Sjostrom said.

Plant-based products that resemble dairy foods do not have standards of identity, and therefore are nonstandardized foods.

The debate is a throwback in some ways to one that played out from the late 19th century up to World War II over the proliferation of margarine in the U.S. In those days, dairy farmers prodded politicians to imposes taxes and fees on the competitor to butter.

Overland remembers that his father, also a dairy farmer, used to bemoan the fact that margarine was colored yellow to make it seem more like butter. Today, he views the labeling of plant-based beverages as "milk" in the same way.

Plant-based drinks are not nutritionally equivalent to milk, he said, yet they have benefited from decades of milk promotion by farmers who raise and milk cows, and are now struggling to stay in business.

"Dairy farmers have spent a lot of money over the years promoting milk, and promoting it as the nutritional product that it is, and they are taking advantage of all of this investment," Overland said.

Plant-based milk alternatives remain a small portion of the beverage market, but they're growing, and sales of dairy products are declining. In the 12 months that ended in July 2018, sales of traditional milk products dropped by 4 percent, while sales of milk alternatives rose by 8 percent.

By far the most popular plant-based milk alternative in the U.S. is almond milk, which is made by soaking almonds in water, grinding them up with more water, then straining out the pulp of the nuts, leaving a white, frothy beverage.

"The marketplace disruption being pushed by the dairy lobby would hinder innovation, create untenable costs for our members, and ultimately be found unconstitutional, making the entire effort a waste of everybody's time and resources," Simon, the director of the Plant Based Food Association, said in a statement. "We encourage the FDA to abide by free market principles and not restrict labeling to unfairly favor the dairy industry."

Simon could not be reached for an interview, and a spokeswoman for the Almond Alliance, a trade association, declined to comment.

A spokeswoman from the FDA said the agency has not set a date for a decision on labeling rules "but will carefully consider the comments before determining next steps."