SENDAI — Radioactive cesium levels above the government’s new limit have been found in beef from Miyagi Prefecture, the prefectural government said.

Meat from a cow shipped by a farmer in Tome was found to contain more than 150 becquerels of radioactive cesium per kilogram, the Miyagi Prefectural Government said Wednesday.

The stricter limit of 150 becquerels for beef and rice took effect Oct. 1. The previous limit was 500 becquerels per kilogram.

It is the first time beef with radioactive cesium levels above the tightened limit has been found.

The cow was shipped to a slaughterhouse in the Shibaura district in Tokyo and a radioactivity check on the meat was conducted Tuesday, the prefecture said. The meat was discarded, officials said.

The prefecture is investigating, suspecting that rice straw eaten by the cow was contaminated by fallout from the Fukushima No. 1 nuclear plant disaster.

Miyagi Prefecture told the farmer not to ship any more cows until the investigation is completed, and asked nearby ranchers to suspend shipments voluntarily.