The Japanese contaminated-beef crisis has widened with the Japanese Government this week extending its ban on cattle shipments to a third prefecture as it moves to protect the nation’s food supply from radiation.

The Japanese Government on Monday banned shipments from Iwate prefecture, the nation’s fifth-largest beef production region, after testing revealed that a number of cattle were found to be contaminated with radioactive cesium.

It follows similar bans on shipments last month from Miyagi and the nearby Fukushima prefecture, prompted after agriculture officials revealed that almost 3000 cattle had eaten hay contaminated by radiation that leaked from a nuclear power plant crippled by the earthquake and Tsunami in March.

Agriculture ministry officials said on July 28 that a total of 2965 cattle that ate tainted feed were shipped to the market from 130 farms in 15 prefectures.

The government may also extend the ban to Tochigi prefecture, south of Fukushima, after discovering cesium exceeding the official standard in beef from the prefecture, according to a Bloomberg news report.

Cattle grown in Iwate, Miyagi and Fukushima represent 10 percent of the country’s herd.

The radiation scare has become the biggest crisis for Japanese farmers since an outbreak of mad cow disease in 2001.

Agriculture ministry prices quoted by Bloomberg said beef prices in Tokyo had slumped, with A-4 grade Wagyu meat plunging to 598 yen ($7.71) a kilogram on July 19, down from 1623 yen on July 1.