Except for some spinach, turnips and white radishes with high radiation levels caught early on by Hong Kong, “hot” food has not entered the market since last March’s earthquake and tsunami damaged a nuclear plant in Japan.

But recently trace amounts of cesium-137 and cesium-134 were found in batches of “Meiji Step” baby milk powder, produced between March 14 and 20 before the March 11 nuclear plant crisis. Kyodo News reported the milk became contaminated with airborne radioactive cesium while it dried.

The levels involved were within safety limits and do not poise a health risk, as long as any one infant’s exposure was limited, officials said. A recall of the 400,000 cans involved is underway.  The powder, sold only in Japan, carries an expiration date of October 2012. 

While even outside experts say the milk power was unlikely to cause harm, news of the contamination caused a sell-off of Meiji Holdings Co. shares on the Tokyo market, ending at a 30-month low.

Since the day after the disaster in Japan, Hong Kong’s Center for Food Safety has been testing radiation levels in Japanese food products. To date, all but the three produce lots out of 56,953 samples of food have been found at or below acceptable radiation levels.

Those tests continue on a daily basis.