ORLANDO, Florida (Reuters) - Those consumers already worried about genetically engineered or cloned food reaching their tables may soon find something else in their grocery carts to furrow their brows over -- nano-foods.

A supermarket aisle in a file photo. Those consumers already worried about genetically engineered or cloned food reaching their tables may soon find something else in their grocery carts to furrow their brows over -- nano-foods. REUTERS/Eric Gaillard

Consumer advocates taking part in a food safety conference in Orlando, Florida, this week said food produced by using nanotechnology is quietly coming onto the market, and they want U.S. authorities to force manufacturers to identify them.

Nanotechnology involves the design and manipulation of materials on molecular scales, smaller than the width of a human hair and invisible to the naked eye. Companies using nanotechnology say it can enhance the flavor or nutritional effectiveness of food.

U.S. health officials generally prefer not to place warning labels on products unless there are clear reasons for caution or concern. But consumer advocates say uncertainty over health consequences alone is sufficient cause to justify identifying nano-foods.

“I think nanotechnology is the new genetic engineering. People just don’t know what’s going on, and it’s moving so fast,” Jane Kolodinsky, a consumer economist at the University of Vermont, said at the conference.

American consumers are generally more complacent about genetically modified or cloned foods than their counterparts in Europe.

But Michael Hansen, a senior scientist with the Consumers Union, said polls show that 69 percent of Americans are concerned about eating cloned meat.

He said that in focus groups run by the U.S. Food and Drug Administration, no parents were willing to feed their children meat from cloned animals or their offspring.

In a recent CBS/New York Times poll, 53 percent of Americans said they wouldn’t buy genetically modified foods.

SCANT AWARENESS

Hansen said there is scant public awareness, however, about foods produced through nanotechnology.

New consumer products created through nanotechnology are coming on the market at the rate of 3 to 4 per week, according to an advocacy group, The Project on Emerging Nanotechnologies (PEN), based on an inventory it has drawn up of 609 known or claimed nano-products.

Nano-products in common use today include lightweight tennis rackets and bicycles, and sunscreens containing clear, nonwhite versions of zinc oxide and titanium dioxide.

They also include lipsticks, and many items labeled as anti-microbial that contain silver ions such as socks, washing machines, salad spinners and food containers.

On PEN’s list are three foods -- a brand of canola cooking oil called Canola Active Oil, a tea called Nanotea and a chocolate diet shake called Nanoceuticals Slim Shake Chocolate.

According to company information posted on PEN’s Web site, the canola oil, by Shemen Industries of Israel, contains an additive called “nanodrops” designed to carry vitamins, minerals and phytochemicals through the digestive system.

The shake, according to U.S. manufacturer RBC Life Sciences Inc., uses cocoa infused “NanoClusters” to enhance the taste and health benefits of cocoa without the need for extra sugar.

The tea, says manufacturer Shenzhen Become Industry & Trade Co., Ltd. of China, is prepared with nanotechnology to “release effectively all of the excellent essences of the tea” and increase by a factor of 10 “the selenium supplement function.”

Hansen, whose organization publishes the nonprofit product-testing magazine Consumer Reports, said there is no requirement that nano-products be identified as such.

He called for stronger federal regulations to require safety testing and labeling.

“Just because something is safe at the macro level, doesn’t mean it’s safe at the nano size,” Hansen said. “All scientists agree that size matters.”

Hansen said recent studies have shown that nano-sized particles in some cases can invade cells and breach the blood-brain barrier, and that some forms of nano-sized carbon could be as harmful as asbestos if inhaled in quantity.

“This represents science at the cutting edge. These technologies raise basic scientific issues,” Hansen said.