Mushrooms joined the threats to Japan’s food chain from radiation spewed by Tokyo Electric Power Co.’s Fukushima Dai-Ichi nuclear plant, as the country expands efforts to limit the effects of the disaster.

Japan is under pressure to enhance food inspections as it has no centralized system for detecting radiation contamination. About two-thirds of Japan’s prefectures now plan to check rice crops, the Mainichi newspaper reported yesterday, citing its own survey. Half of Japan’s rice is grown within range of emissions from the crippled nuclear plant, and farmers are awaiting the results of tests before harvesting begins this month.

‘By strengthening inspection on rice, we want to make sure only safe produce are in the market,