Last year, some Hong Kong customers, after eating hairy crabs shipped from Yangcheng Lake, became ill.

It was thought at first that a bacteriophage (a virus that kills bacteria) had caused the outbreak of illness but later analysis found that the Yangcheng Lake crabs were clean.

"Most probably some inferior crabs with forged brand marks entered the market," said Xiang Chuanfu who runs an exclusive shop selling Yangcheng Lake crabs in Shanghai.

"You know, some small farms might use a bacteriophage to try to cure ill crabs."

Authentic Yangcheng Lake crabs come only from the wide Yangcheng Lake.

"A bacteriophage can be quickly diluted in water, having little effect on the crabs," Gao said.

"For those farmers using big pools to raise hairy crabs, the possibility of spreading a bacteriophage into the pools is also low."

Those who might use a bacteriophage are farmers with small pools where they also raise other seafood such as fish and lobsters.

When fish die, the farmers may need a bacteriophage to kill the bacteria arising from the dead fish and this may affect the crabs.

Small pools do not have a big output but even if just one of the infected crabs went on sale in a market, it could cause trouble.

To ensure safety, the Municipal Government this year is taking more precautions than ever before.

A thorough inspection of the city's main aquatic products markets was conducted recently and no contaminated crabs were detected.

So it seems that locals can feel easy this season when feasting on hairy crabs.

| frontpage | nation | business | HK\Taiwan | snapshots | focus |
| governmentinfo | economic insights | campus life | Shanghai today | metropolitan |