A woman looks at pet food in a store in Beijing, China, 06 Apr 2007

Chinese officials and a Chinese food processing company are giving conflicting statements about whether the company exported a contaminated wheat product to the United States that eventually poisoned scores of cats and dogs. China has a history of food safety problems that experts say could adversely affect its food exports. VOA's Michael Lipin reports from Hong Kong.

The suspect product is wheat gluten, which the U.S. Food and Drug Administration says was contaminated with a chemical called melamine, and sent to the United States. The chemical, which is used in rat poison among other things, was made into pet food that is suspected of causing at least 15 cats and dogs in the U.S. to die.

Other reports in the United States put the number of dead animals in the hundreds.

The Chinese agency that monitors food exports says China has never exported wheat or wheat gluten to the U.S.

The accused company, Xuzhou Anying Biologic Technology Development, at first said the U.S. was its main overseas customer for wheat gluten. But then the company said it had never shipped gluten directly to the U.S.

A company official was later quoted as saying it sold the suspect gluten to another Chinese food processor, and that company "probably" shipped it to the States.

This is the latest in a series of food scares in China in recent years.

The Asian Development Bank warned in January that China's agricultural exports could be adversely affected by such cases.

Chris Spohr, an economist for the ADB in Beijing, says China needs to address the underlying problems that lead to food contamination. He says the Chinese government is making efforts to address its food safety problems.

"It's important to stress that there's been a lot of improvement in recent years, and in some ways, the headlines point to simply a higher level of vigilance in the PRC, along with increased transparency regarding food safety problems," said Spohr.

Fish from southern China's Guangdong province were found last year to be contaminated with malachite green, a poisonous chemical. In another case, poultry in central China's Hubei province were fed with a red dye that potentially causes cancer.

Spohr says China should follow the example of the European Union and Japan, by introducing a universal food safety law with clear leadership by one government agency.

U.S. media reports suggest hundreds of cats and dogs may have died from kidney failure after eating food containing the tainted gluten. A U.S. importer sold the gluten to several pet food makers, all of which have recalled products. The reports have forced one pet food maker to recall almost 100 brands of products made with the ingredient.