Prudence appeared to have prevailed when President Lee Myung-bak’s administration decided not to take any action to halt customs clearance of U.S. beef imports immediately after mad cow disease was found in a dairy cow earlier in the week. Korean officials cited a lack of sufficient information as the reason.

In making the decision, the Korean administration apparently accepted the U.S. assurance, at least for now, that meat from the dairy cow did not enter the food chain and that there was no cause for alarm from the carcass that was under quarantine. The U.S. Department of Agriculture said the case was “atypical” and that the cow was not believed to have contracted bovine spongiform encephalopathy by eating contaminated feed.

No country other than Indonesia has taken any action against U.S. beef imports yet. But the U.S. explanation was not convincing enough to prevent some large Korean retailers from withdrawing U.S. beef products from their shops. According to news reports, Korean customers were shunning them elsewhere.

Mad cow disease is an extremely delicate issue in Korea, which, if mishandled, may spark mass nationwide protests, as it did when the Korean administration decided in 2008 to lift an import ban that had been placed since a case of mad cow was first reported in 2003.

Critics demand imports be suspended immediately. They are already claiming that the administration failed to make good on its promise to stop U.S. beef imports immediately when a mad cow case was reported in the United States.

Indeed in the spring of 2008, the Korean administration promised to immediately halt U.S. beef imports if they were deemed to expose Koreans to health risks when mad cow disease was reported in the United States. It also promised to inspect all U.S. beef products that had already been imported and to dispatch Korean inspectors for participation in local inspections.

The Korean Ministry of Food, Agriculture, Forestry and Fisheries says it is collecting information to determine if the mad cow disease was caused by contaminated feed or took place spontaneously. It adds that it will take measures deemed necessary based on the information.

No undue delay must be permitted in taking steps required to ensure that Korean consumers are not exposed to health risks because of mad cow disease. It goes without saying that a halt to U.S. beef imports must be included among the potential measures to be taken.