Southern Minnesota farmer and broadcaster Jerry Groskreutz was frustrated. Sitting on a panel discussing the public's perception of agriculture, he said the idea that feedlots abused animals drove him crazy.

"Those animals eat better, have better nutrition, better health care, than a lot of people in this world," he told the Farmfest gathering last week.

The overriding theme in the conversation was clear: Consumer attitudes, not farming practices, are the problem.

It's a theme that's been bubbling in southern Minnesota as farmers and food companies struggle to respond to rapidly changing consumer demands. Those shifting preferences are helping produce what the Wall Street Journal recently called "seismic changes" in the food business.

Much of the consumer discontent is focused on how food ingredients are produced on the farm. There are many concerns: genetic modification, pesticides, tillage contributing to global warming, water pollution from farm run-off.

Many of the giants in the food and restaurant industry have heard those concerns and are changing course after seeing sales suffer. McDonald's buys only antibiotic-free chickens now. General Mills is pushing farmers to use more environment-friendly crop production techniques. Supervalu's private label brand of eggs will come only from cage-free birds.

Farmers are definitely feeling pressure. That was clear at Farmfest.

Bob Stallman, president of the nation's largest agricultural group, the American Farm Bureau Federation, said farmers should be left alone to come up with their own solutions.

"We're pretty darn capable of finding solutions on our own out in farm and ranch country," said Stallman. "And we've proven it with respect to the environment and clean water through our conservation efforts."

A panel discussion at Farmfest in Morgan, Minn., on August 5, 2015 brought together, from left to right, American Farm Bureau Federation president Bob Stallman, Minnesota congressman Collin Peterson, National Farmers Union senior vice president Chandler Goule and Minnesota congressman Tim Walz. Mark Steil | MPR News

That's a tough sell to people who worry about agricultural pollution in the Minnesota River or farmer's opposition to Gov. Mark Dayton's plan for buffer strips to curb runoff.

Even some farmers think agriculture is too resistant to change. Brad Trom of southern Minnesota says some farming operations are only interested in squeezing every dollar they can from the land.

"I think Big Ag is acting like a bully," said Trom, a farmer and farm activist with the environmental group Dodge County Concerned Citizens. "They're trying to have their way, no matter what."

The pressure to change could become overwhelming. Right now livestock producers are subject to the most pressure, with undercover stings by animal rights groups and food businesses rejecting the practice of keeping chickens and sows in small cages.

University of Tennessee agricultural policy analyst Harwood Schaffer says consumers who don't like how a product is made are switching to alternatives, and are often willing to pay more for that alternative.

"They've found that they have voice by putting pressure not directly on the farmer, but on the person that they buy the food from," said Schaffer. "And saying 'I'm not going to buy food from you if you don't.' They're going to have to respond to what the consumer wants."

There are growing signs that mainstream Minnesota corn and soybean farmers increasingly will feel a squeeze.

The giant Twin Cities-based dairy cooperative Land O' Lakes, along with General Mills, Walmart and others, have formed a group called Field to Market hoping to use their grain buying power to persuade farmers to raise crops in a more environment-friendly manner.

"We take this very seriously about helping the farmers respond to the market needs of the future," said Keith Newhouse with Land O' Lakes. "We believe that sustainability and being sustainably produced in your products will be part of the future of agriculture."

Right now, Field to Market is promoting efforts to reduce soil loss and increase water conservation. If this model spreads throughout the food industry, the day may come when farmers will have to prove their environmental stewardship before anyone will buy their corn and beans.

Consumers, said Newhouse, are demanding the change.