A cattle farm operator has become Japan's largest corporate failure this year, a victim of growing fears about beef contaminated with radioactive material, dpa cited a research firm as saying Monday. Agura Bokujo filed for bankruptcy protection last week, with total debts of 433 billion yen (5.64 billion dollars), private credit research agency Tokyo Shoko Research Ltd said. The company's revenues were hard hit after radioactive caesium was found in other farm's cows around the Fukushima Daiichi Nuclear Power Station, which caused demand and prices for beef to fall sharply. Agura Bokujo has also been left unable to ship around 3,000 cows within the shipment ban area imposed by the authorities after the contaminated animals were found. The total debts of the company, based 100 kilometres south-west of the plant, had surged to 433 billion yen, up from 62 billion yen as of March 31, the end of the financial year, the research firm said. The Fukushima plant, 250 kilometres north-west of Tokyo, has spewed radioactive substances into the environment since it was crippled by a magnitude-9 earthquake and ensuing tsunami on March 11. Agura Bokujo, a Tochigi-based company established in 1979, runs about 370 farms nationwide mostly through franchising, with 145,000 heads of cattle, Kyodo News reported.