(Updates with comment from consultant in fourth paragraph.)
Dec. 6 (Bloomberg) -- Radioactive cesium was found in milk powder made by a Meiji Holdings Co. unit, causing the shares to fall the most in eight months and raising concern that nuclear radiation is contaminating baby food.
Meiji found traces of cesium-137 and cesium-134 this week in batches of “Meiji Step” made in March, the Tokyo-based company said in a statement today. Levels in the 850-gram (30- ounce) cans are within safety limits and don’t pose a health risk, it said. The investigation was made following a complaint from a consumer last month, a spokesman said.
The finding highlights the radiation threat to food in Japan nine months after the Fukushima nuclear plant was wrecked by an earthquake and tsunami. Prolonged exposure to radiation in the air, ground and food can damage DNA, causing leukemia and other cancers. While infants are especially susceptible, the milk powder may not be a significant threat if contamination is limited to small quantities in isolated batches, said Slim Dinsdale, a food safety consultant based in Norwich, England.
“If it’s just a one-off, ‘safe’ dose then it may well be of a similar level to the background levels” residents are routinely exposed to, Dinsdale said in a telephone interview. “I’d want to avoid cesium if I knew it was there, whether it was a safe dose or not.”
Tests on Dec. 3 and 4 found Cesium-134 at levels as high as 15.2 becquerels per kilogram, while cesium-137 was recorded at levels as high as 16.5 Bq/kg, Meiji said. A becquerel is a measure of radioactivity. The permissible level for milk and dairy products for infants is 200 Bq/kg, it said.
As a result of the tests, the company is recalling 400,000 cans of “Meiji Step,” a powdered milk formulated for babies older than nine months, packaged in April and mostly distributed in May, the company said. All of the affected cans expire in October 2012.
“The dose is pretty small,” said Richard Wakeford, a visiting professor in epidemiology at the University of Manchester’s Dalton Nuclear Institute. It wouldn’t be necessary to ban the products from a radiological protection point of view, he said. “But you can understand the kind of pressure that the manufacturer would be under in these circumstances.”
Meiji shares fell as much as 13 percent in Tokyo, ending trading down 9.7 percent at a 30-month low of 3,020 yen. Rival Morinaga Milk Industry Co. plunged 3.5 percent to a three-year low of 275 yen and Megmilk Snow Brand Co. declined 3.6 percent.
The products were made at a factory in Saitama prefecture, north of Tokyo, between March 14 and March 20, the company said. The raw milk used as the basis for the powder was produced before the March 11 disaster and water used in the production process wasn’t found to be contaminated, Meiji said.
The monitoring didn’t detect radioactive materials from Meiji’s “Hohoemi” brand, the company said.
The presence of cesium at the levels found indicates contamination from nuclear fission products, possibly as a result of explosions at Tokyo Electric Power Co.’s Fukushima plant, said Stephen Lincoln, a professor of chemistry at the University of Adelaide in South Australia.
In a nuclear accident, radioactive isotopes including iodine-131 and cesium-137, which are normally contained inside the fuel rods, may be released into the atmosphere as gases or particulates if the rods are damaged. These can be inhaled or ingested through contaminated food or water. Children are especially susceptible to radiation poisoning from iodine, which can accumulate in the thyroid gland, according to the World Health Organization.
Cesium-137 that enters the body is distributed throughout the soft tissues, especially in muscle. Cesium-137 is eliminated faster from the body than other radionuclides, according to the U.S. Environmental Protection Agency.
--With assistance from Jason Gale in Singapore. Editors: Jason Gale, Marthe Fourcade
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