BEIJING, Nov. 21 -- First it was eggs with red yolks, and now fish with thin, round bodies. It seems pretty things are not supposed to be put on our plates.

Only a few days ago, ducks in some parts of Hebei Province were found to have been fed a special red dye, that later tested positive for carcinogens, so that their eggs would have red yolks. Compared with regular yellow-yolk eggs, these red-yolk eggs fetch a premium price in supermarkets and farmers' markets around the country.

Over the weekend, turbot fish sold in Shanghai were found to contain an element that causes cancer. They have been traced to fisheries in Shandong Province. Further testing revealed that fodder for the fish contained chemicals usually used to treat sick animals.

As one can expect, prices for turbot fish plummeted as authorities began inspections of other fisheries.

But how can a grocery shopper be sure that the next food item they put into their basket is safe to eat?

The harmful eggs and fish were uncovered by random checks by the authorities or the media. While they deserve plaudits for these efforts, it is obvious that such sporadic safety checks which are often clandestine, in the case of media investigations are not enough. There has to be a mechanism to make sure every food item sold is free from harm.

Of course it is unrealistic to test every egg or every fish. But the testing has to be so systematic and foolproof that greedy growers would not even think of using noxious ingredients in their feed. It is too late when inspectors go into overdrive after learning of incidents of mass poisoning or consumer complaints.

Theoretically we do have special departments dealing with food safety. But where were their eyes and ears when a reporter who visited a duck farm heard that farmers never eat their own poultry? Shouldn't that be a tip-off for a sign of dirty dealing?

Something as vital as food safety should not be left to the occasional prying of reporters, who usually do not have the resources or knowledge for this kind of thing. Don't get me wrong. They are doing a great service for public health. But think about it. If professional inspectors did a good job, reporters would not need to carry hidden cameras and smuggle samples to testing labs. If reporters are having a field day on food safety, it can be inferred that those who should do it as a full-time job have failed in the first place.

When a food poisoning scare breaks out, consumers consider themselves the victims, but producers those law-abiding ones who do not inject their poultry or fish with chemicals will be hurt just as badly, if not more. While the whole food category is banned and remaining products condemned, those whose livelihoods depend on it will take the heaviest toll as a result of the bad apples in their midst and the subsequent indiscriminate crackdown and mass panic.

First of all, laws should be scientific. For example, the SK-II scare, though not food-related, showed that laws have to specify the exact level that should not be exceeded by a certain component. The public should be aware that in the real world nothing is pure, and hazard ensues only when the object consumed reaches a certain quantity.

But more often, it is the implementation that should be improved. Unscrupulous merchants would do anything to make a quick buck, and officials protecting consumer safety should be on constant alert to new ways of tampering with products, especially food items, which affect virtually everybody.

It will be a sign of victory for food safety officials when reporters with hidden cameras have a hard time finding story leads for exposes on this topic.