TOKYO （AP） -- Japan has suspended beef shipments from an American meat-packing plant after finding cattle parts banned under an agreement to prevent the spread of mad cow disease, the agriculture ministry said Saturday.

    Japanese quarantine inspectors found bovine spinal columns in one of 732 boxes sent by Tyson Fresh Meats, Inc., which arrived in Japan last month, the Ministry of Agriculture, Forestry and Fisheries said in a statement. The box contained 35 pounds （16 kilograms） of chilled short loin with spinal bones.

    The suspension only affects Tyson's factory in Nebraska, one of 46 meat-packing plants approved to export beef to Japan.

    The Japanese ministry also asked the U.S. Department of Agriculture to investigate how the box containing the banned parts ended up in Japan.

    Japan banned all U.S. beef imports in 2003 after the first case of mad cow disease was discovered in the United States. Japan resumed buying American beef in 2006 after a bilateral trade agreement setting new safety standards.

    Mad cow disease, formally known as bovine spongiform encephalopathy, is a degenerative nerve disease in cattle. In humans, eating meat products contaminated with the illness is linked to variant Creutzfeldt-Jakob disease, a rare and fatal malady.

    Under the bilateral trade agreement, U.S. exporters must remove spinal columns, brain tissue and other parts considered linked to the mad cow disease. U.S. beef shipments to Japan must also come only from cattle age 20 months or younger, which are believed to pose less of a risk.

    Washington has repeatedly criticized Japan for its tough import restrictions, which authorities say have no scientific basis.

    U.S. officials have urged Japan to allow imports of beef from cattle aged up to 30 months, a widely used safety standard elsewhere.

    日本發現從美國內布拉斯加進口的牛肉存在瘋牛病風險，暫停進口

    日本農業部于周六表示，日本發現了從美國進口的牛肉中含有禁止瘋牛病傳播協議中所禁止進口的部分，隨即暫停從美國進口牛肉。

    日本農林漁業部在聲明中表示，檢疫人員在對上月到達日本的732個貨箱進行檢查時發現一箱從泰森鮮肉品公司進口的牛脊肉。該箱包含35磅（即16公斤）的冷凍脊骨腰肉。

    此次暫停進口只影響到內布拉斯加州的泰森鮮肉品公司的業務，該公司是批準向日本出口牛肉的46家肉類企業之一。

    日本農業部門也要求美國農業部就包裝內如何含有日本停產的禁止牛肉進行調查。

    自美國發現第一類瘋牛病后，日本就曾于2003年停止任何美國進口牛肉。但雙方就新的安全標準達成協議后，日本于2006年恢復美國牛肉進口。

    瘋牛病，是牛棉狀腦病的俗稱，是發生在牛身上的一種變性疾病。人類吃了患有此病的肉類產品后會感染克雅病，這是一種罕見的致命疾病。

    在雙方達成的協議下，美國出口商必須去除有可能導致瘋牛病的牛脊肉、腦組織以及其它部分。從美國到日本的牛肉運輸業必須在20個月以下，據說，這是產生危險最小的時期。

    美國一再譴責日本毫無科學依據的嚴格進口限制。

    美國政府官員強烈呼吁日本允許進口30個月大牛的肉，這是其它國家普遍使用的安全標準。