Ned's House of Produce changed the documents accompanying $23,000 worth of Mexican-bound Colorado potatoes to say they came from North Carolina.

The criminal investigation in the case began after a Mexican agriculture official notified U.S. counterparts in July 2000 that inspectors had found a shipment of potatoes infested with golden nematodes (Globodera rostochiensis) in a separate shipment that, according to paperwork, came from North Dakota. The golden nematode lowers potato yields dramatically and is the subject of quarantines around the world.

As a precaution, Mexican officials banned all shipments from North Dakota.

While common in Europe, in the US the golden nematode is known to occur only in a few counties in New York state.

Prior to 2003, Mexican regulatory officials had banned potatoes from Washington, Oregon, Colorado, California, Nevada and Idaho.

U.S. investigators found that a number of people in the chain between potato fields and Mexican shipments had lied about the true source of potatoes. There were violators in California, Arizona, Colorado, New Mexico, Oregon and Washington.

In 2003, the Mexican government lifted the ban on Western potatoes and changed regulations so that individual exporters, rather than whole states, were regulated.

Some western US potato growers believe that the ban is not really about pests, rather that Mexican officials are concerned about the economic impact on their own growers.