US organic farming group The Cornucopia Institute has filed a complaint against US retailer Target Corp. over the alleged "misleading" sale of organic products.

The complaints, filed with the US Department of Agriculture's organic programme, and Wisconsin and Minnesota officials, alleges that Target has misled consumers into thinking some conventional food items it sells are organic.

The institute claims that the complaints are the "latest salvo" into a growing controversy where corporate agribusiness and major retailers have been accused of "blurring the line" between "natural" products and food that has been grown, processed and properly certified organic under tight federal standards.

This is not the first time The Cornucopia Institute has accused a retailer of misleading consumers with organic products.

In 2006 the Institute filed a complaint with the USDA accusing Wal-Mart of illegally selling non-organic food products as organic. The Institute claimed to have documented cases of non-organic products being sold as organic by the world's largest retailer.

"Major food processors have recognised the meteoric rise of the organic industry, and profit potential, and want to create what is in essence 'organic light,' taking advantage of the market cachet but not being willing to do the heavy lifting required to earn the valuable USDA organic seal," said Mark Kastel, senior farm policy analyst at Cornucopia.

The Wisconsin-based policy group has pointed to Target's nationally advertised Silk soymilk, advertised using the term "organic" pictured on the carton's label. Cornucopia says that producer Dean Foods had quietly shifted its products away from organics.

Target's own upscale private-label food line, Archer Farms, has also come under scrutiny, with Cornucopia claiming the range blurs the line selling both natural and organically labelled food. Its organic milk supplier Aurora Dairy was said to be "flagrantly violating" federal organic livestock standards.

"In an industry where educational achievement and passion are the common denominators in describing its clientele, Target could certainly be viewed as arrogant to think they can take advantage of consumers by ignoring both the spirit and letter of the laws governing organic commerce," Kastel said.

Officials at Target and Dean Foods could not be reached for immediate comment.