Monsanto on Monday won another round in a legal battle with U.S. organic growers as an appeals court threw out the growers' efforts to stop the company from suing farmers if traces of its patented biotech genes are found in crops.

The U.S. Court of Appeals for the Federal Circuit affirmed a previous ruling that found organic growers had no reason to try to block Monsanto from suing them as the company had pledged it would not take them to court if biotech crops accidentally mix in with organics.

Organic farmers and others have worried for years that they will be sued by Monsanto for patent infringement if their crops get contaminated with Monsanto biotech crops.

In its ruling Monday, the appellate court said the organic growers must rely on Monsanto assurances on the company's website that it will not sue them so long as the mix is very slight.

"Monsanto's binding representations remove any risk of suit against the appellants as users or sellers of trace amounts (less than one percent) of modified seed," the court stated in its ruling.

Monsanto officials applauded the ruling.

"The assertion that Monsanto would pursue patent infringement against farmers that have no interest in using the company's patented seed technology was hypothetical from the outset," the company said in a statement issued Monday.

Monsanto has developed a reputation for zealously defending patents on its genetically altered crops, which include patented "Roundup Ready" soybeans, corn and cotton, genetically altered to tolerate treatments of its Roundup weedkiller.

The crops are widely used in the United States and Latin America. It has proven difficult to keep the genetic alteration from contaminating non-biotech crops, as recently occurred in a wheat field in the U.S. state of Oregon.

The group of more than 50 organic farmers and seed dealers sued Monsanto in March 2011 seeking to prohibit Monsanto from suing them if their seed and crops become contaminated.

Monsanto officials specifically refused to sign a covenant stating it would not sue the growers, but the court said the website statement was sufficient and would be binding.

Andrew Kimbrell, a lawyer with the Center for Food Safety, which joined as a plaintiff in the lawsuit, said the decision made no sense.

"It is a very bizarre ruling that relies on a paragraph on a website," he said. "It is a very real threat to American farmers. This is definitely appealable."

In its ruling Monday, the court noted that records indicate a large majority of conventional seed samples have become contaminated by Monsanto's Roundup resistance trait.

Monsanto filed 144 patent-infringement lawsuits against farmers between 1997 and April 2010, and won judgments against farmers it said made use of its seed without paying required royalties.

Many U.S. farmers have said their fields were inadvertently contaminated with Monsanto's biotech seeds without their knowledge. The issue has been a topic of concern for not only farmers, but also companies that clean and handle seed.