South Korean food exports to Japan are climbing at their fastest pace on record after radioactive contamination and supply disruptions prompted consumers to switch to overseas producers.

Sales of watermelons, tuna and noodles led a 38 percent jump in South Korea's shipments of food to Japan to $604 million in the second quarter from a year earlier, according to the Korea International Trade Association (KITA).

Surging demand for South Korean products has helped buffer exporters against weakness in U.S. and European markets. Lotte Chilsung Beverage Co.'s drink sales to Japan have more than doubled and its shares have risen 58 percent since the March temblor and tsunami that triggered the Fukushima nuclear crisis.