WASHINGTON – Some farmers are worried that a Maine federal court ruling requiring that the Agriculture Department must come up with stricter standards for organic food will slow the fast-growing industry.

Consumer advocates say the decision will help ensure that people get higher-quality food when they buy products with the organic label.

U.S. District Judge D. Brock Hornby issued a ruling this month that bans synthetic ingredients in products labeled organic. Also, the ruling requires dairy farmers to feed their cows 100 percent organic feed during the transition to organic.

In a lawsuit against the department, a Maine grower of organic blueberries, Arthur Harvey, contended the current regulations violated the Organic Foods Production Act of 1990.

The organic dairy industry says the new regulations would make it more expensive for dairy farmers to convert to organic because organic feed can cost two or three times more than conventional feed. Advocates are considering going back to Congress for a legislative remedy.

The department declined to comment about the court case or what it would do about the standards.

“We think this will discourage dairy farmers from becoming organic,” said George Siemon, chief executive of Organic Valley, a national farmer-owned organic cooperative based in La Farge, Wis. “I think it will slow down supply and buyers will have to contribute more to the cost.”

Demand for organic milk has risen steadily as consumers seek products free of pesticides and antibiotics.

The court gave the department one year to develop new regulations; the agency would then have an additional year to phase them in.

Current regulations allow dairy farmers who want to go organic to feed their cows 20 percent conventional feed and 80 percent organic feed in the first nine months of the transitional year. That goes to 100 percent for the last three months.

Milk can be labeled organic only after the transitional year.

Members of the U.S. House Organic Caucus recently wrote Agriculture Secretary Mike Johanns to warn that the decision “could decimate every sector of the organic industry.” The lawmakers did not call for a change in law, but said they wanted to work with Johanns to resolve the conflict.

Six agriculture, retail and food safety groups, including the Center for Food Safety, have asked the department to develop strict standards in the wake of the court ruling.

Jerome Walch, who has a 50-cow dairy farm near Rochester, Minn., about 90 miles south of Minneapolis, is in the process of converting to organic. He said he still hopes to go through, but now worries about the economics.

“We’ll be selling milk at conventional prices, but buying feed at organic prices,” Walch said. “I can buy conventional corn feed for $1.78 a bushel. Organic corn costs $5 to $6.”

Urvashi Rangan, an environmental health scientist at Consumers Union in Yonkers, N.Y., said farmers and consumers will benefit from the ruling in the long run.

“It’s a big victory for consumers, as far as the integrity of the organic label and what it means,” Rangan said. “This will increase the value of the organic label.”

She said that fears about slowing the growth of the industry are shortsighted.

“What we don’t want to get into is lowering standards so more of the market can meet the standards,” Rangan said. “We want to see a steady increase in strength and rigor of the standards over time. Those who do meet those higher standards will ultimately be rewarded in terms of premium for their product.”

The court decision does allow for the use of some synthetic ingredients in products labeled “made with organic,” but not in products with the more coveted “organic” label.

Among those likely to be affected are baking powder and pectin, a gelling agent used to make jam and jelly.

Katherine DiMatteo, executive director of the Organic Trade Association, based in Greenfield, Mass., said the industry has spent a lot of money in market development and customer recognition.

“It’s unfortunate to have changes made at this early stage in the industry and implementation of the law,” she said.