Can meat grown in a lab still be called meat? Can milk that comes from nuts rather than cows bear the name milk? And can mayonnaise made without eggs still be called mayo?

From oat milk to grain-based burger patties to mayo made from yellow peas and canola oil, alternative products now populate nearly every aisle of the grocery. Makers of alternative foods, usually from plants, use the terms to signal how their products can be used.

But farmers see the new foods as a threat and want the federal government to restrict words like milk, cheese and meat to products that come from animals.

The FDA appears poised to reconsider terms. "It's important that we take a fresh look at existing standards of identity in light of marketing trends and the latest nutritional science," FDA Commissioner Scott Gottlieb said in March.

Some see a risk of confusing consumers, who may think the new products have the same origin as the ones they've long known. Chocolate-flavored dairy milk is called chocolate milk, for instance, but cashew milk is strained from a mixture of ground cashew paste and water.

Another part of the confusion is tied to the origin of the new products. In meats, the new alternatives that are coming out of labs still use animal cells.

The debate intensified recently when Cargill, Tyson and billionaires Bill Gates and Richard Branson invested in Memphis Meats, a Berkeley, Calif.-based company that takes animal cells and cultivates them into meat. It produced a meatball in 2016 and its first poultry product last year.

Minnetonka-based Cargill is one of the world's largest processors of beef, so cattle ranchers took its involvement as a serious omen: It's not a matter of if, but how soon, lab-raised meat becomes a player in the market.

In February, the U.S. Cattlemen's Association petitioned the U.S. Agriculture Department to limit the definition of "beef" and "meat" to products made from live animals slaughtered in a "traditional manner."

Asked about the debate, Cargill referred questions to the North American Meat Institute, a trade group for meat processors that opposes the Cattlemen's Association's stance.

"Science evolves, so does technology," NAMI wrote in its own comments to the USDA. "The term 'meat' was fairly broadly defined by the agency decades ago, and imposing today the artificial limitation requested by the petition could impede tomorrow's progress."

Plant-based alternatives are not new, but the rate of food innovation is accelerating not just in quantity, but quality, said Josh Resnik, chief executive of Wedge Community Co-op, a natural foods grocer in Minneapolis. "The number of new items in those categories is staggering," he said. "The quality ... compared to five or 10 years ago is night and day."

The growth in alternatives dovetails with another consumer trend: rising demand for protein. American consumers are looking for new ways to pack it into their diets, said David Portalatin, a food industry adviser at the NPD Group, a consumer research firm. "Plant-based is growing because it is all about protein," he said.

A survey published last week by NPD Group found that 86 percent of people who buy plant-based alternatives are not vegans or vegetarians. Instead, they are meat eaters adding these products into their existing diets. Packaged food companies, like meatpacker Hormel Foods Corp., recognize this trend and have broadened their portfolio to include non-meat products.

Last year, the Austin, Minn.-based company launched a new beverage called Evolve made from pea protein. The brand is run by its CytoSport business, which also makes Muscle Milk, a protein shake derived from dairy.

"With the groundswell of more people entering the market, plant-based proteins really jumped off the page with a great deal of momentum," said Jason Hull, Evolve's brand manager. "We saw this brand as having an emotional tie with consumers, rooted not only in great taste, but in living that sustainable life."

And while many consumers may just mix plant-based options into their protein repertoire, there is evidence of alternatives replacing traditional meat and dairy products. Plant-based meat alternatives claimed 2.1 percent of U.S. sales in refrigerated and frozen meat products, according to a Nielsen data study commissioned last year by the Plant Based Foods Association and the Good Food Institute.

Meanwhile, plant-based milk composed 9.3 percent of milk sales while plant-based cheeses, yogurts and ice creams are growing 20 percent annually. "The meat people look and see that nearly 10 percent of dairy sales are now going to plant-based products and are thinking 'That could happen to us,' " said Dick Wegener, a food lawyer at Faegre Baker Daniels in Minneapolis.

U.S. Sen. Tammy Baldwin from Wisconsin last year introduced the Dairy Pride Act to pressure the FDA into enforcing its definition of milk. If passed, "milk" would be reserved for products from one or more lactating cows.

The FDA has been relatively hands-off with the growth in nondairy milk products. "There has been a tacit understanding that consumers are not misled by those terms," Wegener said. "If consumers were being confused, the FDA might have been more solicitous of these petitions that have been filed."

Many of the FDA's traditional food definitions, called Standards of Identity, are decades old and are essentially recipes. Milk was first federally defined 45 years ago while cheese was defined 77 years ago.

Groups pushing for enforcement of these definitions often cite consumer protection concerns. And while these standards may have originally been designed to protect consumers, Wegener said, they've become vehicles for industry to entrench their products and protect themselves from competition. "These events bring into clear focus the shortcomings of the role Standards of Identity really plays in today's food world," Wegener said. "They are largely outdated and the argument can be made that they stifle innovation and they prevent healthy foods from coming to market."

The FDA's Gottlieb, in his March comments, said the agency may revisit standards that are no longer necessary. He added, "We also see a need for flexibility in standards that allow better public health outcomes by encouraging manufacturers to produce more healthful foods that are still affordable."

Grocers and consumer researchers believe people who buy alternative products educate themselves about what the foods actually are and know what they are getting.

"We have got to give the American consumer a little more credit. They are more informed than at any other time in history," Portalatin said. "It's on the manufacturer to establish a level of trust."