But in many ways, the debacle over StarLink, the corn at the center of the recall, was great advertising for Jim Mock's business. He co-founded a company that sells certification systems for farmers and buyers who want to trace and identify crops from the seed stage forward.

"As food production gets more specific, there's a real need to be able to trade the products from the point of origin to the sale," said Mr Mock, an agronomist and a vice president with CropVerifeye.com.

Several companies, including tractor giant John Deere & Co showcased crop segregation and certification systems this week here at the annual convention of the National Corn Growers Association and the American Soybean Association.

Mr Mock and others at the meeting made clear that certain high-value crops, such as food-grade soybeans that can be used in tofu or crops for pharmaceutical or "neutraceutrical" uses, have an obvious interest in ensuring they don't get commingled with other grain varieties.

Practicing what the grain industry calls "identity preservation," or IP, isn't cheap. The high-tech systems sold by CropVerifeye and other competitors involve tracking devices such as computerised bar-code tags that growers stick on seed bags and field equipment.

Also consider the computer software to collect the data on the tags and keep a record of the seed in each field, or the fees for independent auditors who make on-farm visits to make sure everything is done right.

New players also charge a monthly fee to maintain updated records on the Internet that growers and buyers can access.

Mr Mock estimated that his company's IP system added roughly 2 to 3 cents to the cost of a bushel of corn and 5 to 8 cents per bushel of soybeans. But as the StarLink fiasco showed, a broken link in the identity chain can spark million of dollars in damages and untold aggravation.

Starlink's developer Aventis CropScience, a unit of Aventis SA has been hit by a wave of class action lawsuits in the US by farmers and grain handlers who have seen their corn supplies devalued by positive Starlink tests."StarLink forced a lot of people in agriculture who say, `I don't know if I can afford to do this,' to say, `This is really important,'" said Identity Preserved.com's Phil Neff. "It's a shame, but I think in the long run it's good for agriculture."

Mr Neff said his South Dakota-based company was working with Aventis SA to help locate and track what little of the unapproved corn still remained in US farm storage bins.

Some say StarLink corn remains as an isolated case, and that most farmers won't bother with the expense of keeping crops separated if they don't absolutely need to.

National Corn Growers Association president Lee Klein said it's naive for seed companies to expect producers to behave otherwise.

"You're never going to get segregation if there's not a profit to do it. It's imaginary," said Mr Klein. "If I'm going to harvest and a storm is coming...It's not going to happen unless there's a high value to it."In fact, the US grain handling system was built on the idea that graded commodities such as corn were basically the same everywhere for purposes of trade. The fact that grain is undifferentiated keeps costs down for handlers and buyers, in addition to making futures exchanges with "fungible" or interchangeable bulk commodities possible.

But those in the IP trade say the food industry is shaking that foundation by now seeking particular traits in specific ingredients. Companies are also interested in quality standards that can be certified, as in any other manufacturing inputs.

The driving force behind the food companies, Mr Mock said, is consumers who are demanding more safety assurances and information about where their food comes from. "Ultimately,", he said, "the consumer will say, `I want to know what's in there.'"

In line with adding IP crops, Mr Mock and Mr Neff said farmers are showing more interest in contract farming, in which a buyer such as a food company or processor contracts with a farmer to produce crops under certain specifications.

Not all producers are comfortable with the idea. "The perception of saying `I'm just a hired tractor driver,' that's not what we want," said the NCGA's Klein. "But we really do that now. That's what people are doing (by) raising white food-grade corn."

Snacks producers such as Frito-Lay have for several years used contract producers to supply their white corn for chips. With grain prices stuck in a rut, contracting with a guaranteed buyer and using an IP-type certification process can help growers boost the value of their crop.

"There's an opportunity to add a premium," said Mr Mock. Mr Neff and Mr Mock said their systems both have Internet components that allow buyers to keep track of the progress of a contracted crop from anywhere in the world. One dealer compared the concept to shipping companies tracking customers' parcels.

Certifying a crop can also help food companies differentiate their brands. "A traceability system should enhance the value of the product, all along the chain," Mr Mock said.