Unlike pet dogs, whose only function is to wag their tails and amuse, watchdogs exist for practical reasons - they are supposed to bark to alert their owners of potential dangers.

That is why we refer to consumer protection agencies as watchdogs, and generally endorse their existence as indispensable arms of the government. Just like watchdogs are kept to ease worries about safety, we cherish the innocent belief that such institutions can substantially reduce our exposure to risks, especially when it comes to what we eat. And that is why, in spite of all the complaints about inefficiency and dereliction of duty, there has been little opposition to the game of assigning new caretakers.

Few can tell precisely how many government agencies are now responsible for food safety in the country. To most of us at least, the obvious answer is "many". But we do not care, at least for now, as long as they work.

The biggest risk to those who keep a watchdog, or like us, more than one, is not finding themselves in harm's way. It is rather the usually improbable scenario that their guard dogs become insensitive to signs of threat. Having a watchdog that does not perform what is expected of it is even worse than not having one, because we ourselves are generally less vigilant with one of them at our side.

We have a number of government offices with responsibilities for food safety. But the quality inspection authorities have effectively sunk themselves in public distrust through the never-ending drama of melamine-tainted milk. Now it is the industry and commerce authorities' turn to take a public confidence test.

Though in almost identical uniforms, industry and commerce officials are not like chengguan (city urban management) officers, who seem to do all the bad things without due authorization. In fact, industry and commerce administration officials can do everything - from confiscating problematic goods to suspending a business - necessary to detect and address misconduct in the market. Yet an otherwise minor recent episode in Beijing has raised questions about the local industry and commerce administration's effectiveness as a watchdog.