To ensure that the nation's animals remain healthy, the Chinese government announced it is stepping up efforts to interdict tainted products at its borders.

And backing up these efforts, Shanghai researchers have developed a new gene-based technique for detecting potential problem imports and have tested a new vaccine that may help prevent the spread of foot-and-mouth disease.

The advances are part of a longstanding program to keep China's livestock free from the scourges that have hit other regions of the globe.

As early as 1986, the central government began banning imports of animal products from countries affected by the degenerative brain disorder in cattle known as mad-cow disease.

As new outbreaks were reported, the State Entry-Exit Inspection and Quarantine Bureau issued an emergency notice to entry ports nationwide at the end of last year, banning animal feed from the European Union and any other affected countries.

On Friday, a new ban was imposed, this time on animal products from countries involved in the growing outbreak of foot-and-mouth disease, a highly contagious viral illness that causes fever and blisters in cattle and other cloven-footed animals.

Inspectors at ports of entry throughout the country remain on the alert. And shipping procedures have been tightened.

In Shanghai, for example, domestic importers must apply for a permit to state entry-exit authorities if they want to bring in animal products. When the goods arrive here, inspectors confirm their certification and test samples of the products, said Liu Xuezhong, director of the bureau's animal and plant supervisory division.

The gatekeepers are being aided by a new method developed by local scientists for detecting any cattle components in imported animal feed.

Using a technique that "magnifies" DNA, scientists from the Shanghai Entry-Exit Inspection and Quarantine Bureau and the Shanghai Academy of Agricultural Sciences managed to detect cattle genes in an animal feed sample.

Bureau officials claim the method is highly effective - an important breakthrough since mad-cow disease is often transmitted through feed that contains the ground bones of infected cattle.

"We can detect even 0.1 gram of a cattle component in 100 grams of animal feed," said Chen Jiahua, the bureau's senior engineer.

A new genetics-based vaccine for foot-and-mouth disease, developed by Fudan University and Shanghai Academy of Agricultural Sciences, has been tested in pigs, but further research is needed before it can be put into use on the farm.

An estimated 50,000 tons of beef are imported from countries where mad-cow disease has not been found, including the United States, Australia and Canada, Zhang said.

(Eastday 03/21/2001)