The U.S. Department of Agriculture is cracking down on businesses selling fake organic products. Most recently, a businessman with the largest organic fertilizer operation in the West pleaded guilty to fraud charges last week. Kenneth Noel Nelson, Jr., of Bakersfield, Calif., pleaded guilty to four counts of mail fraud for selling organic fertilizer that was not organic. He faces 20 years in prison and a $250,000 fine. He will be sentenced in November.

Nelson is one of the largest fake organic businessmen USDA has caught. According to the Department of Justice, His company, Port Organic Products Ltd., sold approximately $40 million worth of the fertilizer from 2003 to 2009. He did not disclose to customers that the fertilizer contained aqueous ammonia and ammonium sulfate. He even obtained his organic certification with false applications.

Nelson’s actions put many organic farming operations in jeopardy of losing their organic certification.

USDA investigators appear to be stepping up their enforcement of organic rules. Long criticized for not enforcing the rules, USDA is now beginning an “age of enforcement,” according to USDA investigators. Organic groups appear pleased with the stronger enforcement.

“I think anything that will increase the integrity of organic fertilizer and organic agriculture is very important,” Steve Beckley, the president of the Organic Fertilizer Association of California told the Miami Herald.

Nelson isn’t the only high profile person to get caught. In April, an Oregon man was sentenced to 27 months in prison for “selling millions of pounds of corn falsely labeled as organic.” In another case, the owner of California Liquid Fertilizer pleaded guilty to fraud for using banned chemicals in its “Biolizer XN” fertilizer, which was sold as organic. Peter Townsley is awaiting sentencing after the two-year investigation as a result.