It is the first report that home-grown food has been contaminated by radioactivity, largely Iodine(碘)-131, since the ministry ordered radiation( powerful and harmful rays that are sent out from radioactive substances) tests on food and water at the end of March in 14 mainland regions including Beijing, Tianjin, and some coastal provinces.
Sample inspections conducted on Tuesday found low levels of radioactive iodine in spinach( a kind of green vegetables) planted in Beijing, Tianjin and Henan province --- about 1-3 becquerels per kilogram (Bq/kg), the statement said.
"The contamination level detected is too low to be harmful to public health," it said.
According to health experts, radioactive iodine can accumulate in humans once ingested in high concentrations and increases the risk of thyroid cancer. But it decays naturally within weeks.
Leafy vegetables grown in the open like spinach, lettuce and leek are among the first foods to be tainted by radioactive deposits.
Raw milk is also susceptible to radioactive contamination as livestock feed on grass.
Tests carried out in March showed spinach and milk taken from farms near Japan's nuclear-stricken area had exceeded(go beyond) government-set safety limits for radiation.
No cases of tainted water or milk have been reported in China but the ministry vowed to further strengthen monitoring.
Wang Zhongwen, a researcher at the China Institute of Atomic Energy's radiation safety department, told China Daily on Wednesday that currently China only had the means to conduct food radiation tests in a few regions.
The statement also said that recent rain in Beijing and Tianjin meant radioactive substances could have fallen on vegetables.
Chen Jicang, a vegetable dealer in Beijing, said on Wednesday that concerns are growing among consumers, businesses and governments across the world.
"We have yet to see any impact on our business from the radiation, but we will keep a close eye on how the issue develops," he said.
He added that most vegetables consumed in Beijing are produced locally, and he might switch to other varieties if spinach sales suffer.
Yang Guoshan, a researcher of radiation medical science at the Academy of Military Medical Sciences, said people could safely eat products that contain low levels of Iodine-131.
"The radiation level is so low that residents don't need to spend any extra effort on cleaning them," he said.
Gao Jie, a 52-year-old resident in Tianjin said she is deeply worried because spinach is a staple part of her family's diet.
"If spinach is radioactive, is there any possibility that other types of vegetables are safe?"
Trace levels of radioactive isotope cesium-137 and -134 were detected in the air in 21 provinces and regions on Wednesday, up from 17 on Tuesday, according to China's National Nuclear Emergency Coordination Committee.
What does the underlined word mean in para 1?

A．protected

B．contained

C．polluted by dangerous substances

D．tested

Why are the spinach and milk taken from nuclear-stricken area not safe?

A．Because tests have been carried out there.

B．Raw milk is sensitive to radioactive contamination as livestock（家畜）feed on grass.

C．The amount of radioactive substances goes beyond the safe limits for radiation.

D．Japan is a nuclear-stricken area.

Where do you think this passage comes from?

A．a magazine

B．CCTV news

C．a journal

D．a novel

What is not mentioned in the passage?

A．Consumers became concerned about the safety of vegetables.

B．People need to clean vegetables completely before cooking because of radiation.

C．Food and water have to be tested since the end of March in 14 mainland regions

D．Low levels of radioactive iodine has been found in spinach in Tianjin

What do you think is mainly talked about in the passage?

A．How the radioactivity came into being

B．What we should do in face of radioactivity.

C．Radioactivity has no side effect on human being.

D．Home-grown food has been affected by radioactivity.