By Kari Huus, msnbc.com reporter

Japanese beef from cattle raised in the region of the country’s damaged nuclear reactors registered high levels of radioactive cesium, officials in Tokyo said, prompting Japan’s central government to mandate an expansion of its meat monitoring program.

The Tokyo metropolitan government said this weekend that testing had detected radiation levels of three to six times the legal limit in beef from 11 cows shipped to Tokyo this month from Minamisoma city, located just outside the 20-mile no-go radius around the Fukushima Daiichi power plant.

The level of contamination is not high enough to cause any acute symptoms even if consumed. The limits are set according to risk from prolonged consumption. But the finding suggests gaps in Japan’s food safety program in the wake of the earthquake and tsunami disaster that battered the nuclear plants in March.

“The message is 'get your safety survey protocols together otherwise people will simply not buy from that area,' ” says Kathryn Higley director of Oregon State University's Department of Nuclear Engineering and Radiation Health Physics. “It’s a matter of confidence.”

The beef samples from 11 cows that were shipped from a single farm showed levels of radioactive cesium from 1,530-3,200 becquerel per kilogram, compared to the legal limit of 300 becquerel per kilogram, according to Tokyo metropolitan government.

None of the meat from these 11 animals entered the market, but the findings raised concerns about other meat from the same farm that previously had been sold into the market.

The contamination was not surprising, says Higley, and echoes what happened following the Chernobyl nuclear disaster in Ukraine in 1986.

“When they had their big releases back in March there were puffs of (radioactive) material that came out, and just deposited on the surface. As the grasses and crops grow up through the material they get coated, and take it up through the roots,” says Higley. “If the cows are within the contaminated area, they are going to eat grasses, and it distributes itself in the muscle.”

The Chernobyl disaster prompted many European countries to develop extensive protocols for determining whether livestock raised in the contaminated region was fit for market.

In March, the Japan’s central government ordered the destruction of livestock within the no-go zone, and instructed other farms in the region not to use livestock feed that was outside at the time of the radioactive releases.

But as local officials began to measure radiation in livestock feed at dozens of farms, it became clear that the farm producing the contaminated cattle had not followed that order. Radiation on the hay fed to the cattle measured about 56 times the legal limit, according to Japanese press reports.

In addition, earlier testing of the cows conducted locally detected no radiation on their skin, according to Kyodo News agency, citing officials in Fukushima prefecture.

Ministry of Agriculture, Forestry and Fisheries said Monday it will strengthen its monitoring of cattle meat in Fukushima, and the nearby prefectures of Miyagi, Yamagata, Ibaraki, Tochigi, Gunma and Niigata, according to Kyoto.

A senior health official told NHK television on Monday that if necessary, the government would begin testing all the meat of cows shipped from farms in areas surrounding the crippled power plant to ensure its safety.

Since the March 11 disaster, which led to a partial meltdown at the Daiichi plant, Japanese authorities have detected radioactive cesium above legal limits in Japanese tea leaves and in plankton on the ocean floor in the region.