A recent email warning of chocolate possibly contaminated with melamine is again raising concern about products originating from China.

The e-mail specifically references an Oct. 8 recall notice by the Canadian Food Inspection Agency, urging the public not to eat or distribute Sherwood Brands Pirate's Gold Milk Chocolate Coins because they may contain melamine.

The foil-wrapped, coin-shaped candy is sold nationally through Costco stores and may have been sold in bulk packages or as individual pieces at various dollar and bulk stores across Canada, according to the recall notice.

Melamine is a synthetic chemical used to make plastics, fertilizers and pesticides. The chemical does not occur naturally in food; it was blamed for last year's huge pet food recall that sickened or killed hundreds of pets.

Earlier this year, more than 50,000 infants in China became ill, and at least four died, after consuming formula laced with melamine.

High levels of melamine have recently been found overseas in eggs shipped from China.

Low levels of melamine are not harmful, but exposure to high levels, or exposures to lower doses of melamine together with certain other chemicals, can cause urinary tract problems, according to the U.S. Center for Disease Control.

Symptoms of melamine exposure include stomach pain, vomiting, fever, irritability, blood or crystals in urine, painful urination or swelling in the hands, feet or face.

There have been no human illnesses traced to melamine in the United States, said Hal Prince of the Maine Department of Agriculture, which works with the U.S. Food and Drug Administration to monitor food quality and safety.

But the FDA is particularly doubtful of products whose production is connected with Asian markets.

The administration has recalled a number of products sold here due to suspected melamine contamination, Prince said, including Blue Cat brand flavored drinks, White Rabbit candy, Mr. Brown coffee and teas, and Koala's March creme-filled cookies $ all of which raised concerns about possible melamine contamination.

"We're working with the FDA on this recall," Prince said. "The FDA has been very aggressive about testing any products they suspect might have melamine in them."

But products made by Sherwood Brands, the maker and distributor of the chocolate coins, have not been recalled in the United States, Prince said, and a notice to customers on the Sherwood Brands Web site assures that none of the suspect chocolate was sold in this country.

The company has implemented a testing program through independent labs upon the FDA's warning about possible melamine contamination in milk-containing products form China.

Sherwood Brands' release calls the Canadian recall an "isolated situation."

"Sherwood Brands has not received any chocolate in the U.S. from China since the report of melamine," the company said. "All products now shipped to both Canada and the United States are first tested for the absence of melamine prior to shipment."