South Korean flour mills will resume buying soft white wheat from the Pacific Northwest, the first major break in frozen export sales since genetically modified wheat plants were found growing in an eastern Oregon field this spring.

Korea will continue testing wheat shipments for the presence of transgenic material, but will not restrict purchases of wheat grown in Oregon, said Blake Rowe, chief executive of the Oregon Wheat Commission.

Korea and Japan, the biggest buyers of Pacific Northwest wheat, suspended new purchases after the “Roundup Ready” wheat plants were confirmed in May. Both countries accepted deliveries of wheat purchased before the discovery, but implemented testing procedures and have sought assurances that genetically engineered wheat has not entered the commercial stream.

Japan is the largest buyer, and both nations use wheat from Oregon, Washington and Idaho to make noodles, sponge cakes and crackers. They are adamantly opposed to importing genetically modified food.

State and federal agriculture officials are working with their Japanese counterparts, trying to negotiate a resumption of sales. Meanwhile, the U.S. Department of Agriculture continues to investigate how the rogue plants emerged in the Oregon field.

Japan has not returned to the market yet.