As the scope of the food scandal widens in Taiwan - more than 200 firms and 500 products have been involved so far - some tainted commodities have been discovered in the mainland and the ripples of the DEHP scare here call for a further response on the part of the authorities.

The General Administration of Quality Supervision, Inspection and Quarantine has made the sensible decision to suspend the imports of Taiwan firms whose products have been confirmed as problematic. That was a necessary move, yet it is sufficient only to prevent a potential threat to public health from broadening further.

At this point, the top priority for the safety authorities should be tracking down and recalling all the suspected beverages, snacks and perhaps raw materials from Taiwan.

And it will do so, only if the quantity of problematic products in the mainland market is very, very small, as has been claimed by the companies themselves, and all of them are retractable.

However, given the toxic nature of the plasticizer DEHP, its reportedly long existence in Taiwan's food industry, as well as the latest report that the harmful substance was discovered in imported cosmetics, it might be more meaningful if the inspection extends beyond the designated items and product batches.

Since some of the firms involved in the DEHP scandal have mainland subsidiaries, consumers need to know whether the food products they make and sell here are safe or not.

Some of the firms involved have already claimed their mainland companies have independent suppliers, so their products on the mainland are free of DEHP. It would be wonderful if that is the truth. But that statement needs to be confirmed. And this is where our quality watchdogs should step in.

Aside from worries about food products made in Taiwan, consumers here are wondering if DEHP, or any similar additive, has been used by local manufacturers. Since no inspection has been targeted specifically at DEHP, nobody can provide a definite answer. But considering the potentially high stakes, there has to be one.

And we do not think it is a good idea for our authorities to wait until DEHP's existence in food products becomes prevalent to launch a probe.

Some speculations about the existence of DEHP in mainland food sectors might turn out to be groundless in the end. But because of its hazardous potential, even as a pre-emptive step, it is essential we act early.