“There are practically no cases of radioactive watermelons this year,” was the triumphant announcement of Andrei Buyanov, one of Moscow’s corps of atomic food inspectors. Unfortunately for Muscovites, there were plenty of other radioactive fruits and vegetables. Moscow is 415 miles from Chernobyl, where an atomic reactor blew up in 1986; food found in the region can still be contaminated. Last year, inspectors seized more than 3,000 pounds of radioactive food bound for the stalls of the city’s 69 outdoor markets; this year, they expect to haul in 10 percent more. The riskiest foods are those foraged in forests — mushrooms, berries, and the like, which are generally handpicked in the wild, making them harder to monitor than food grown on farms. Mushrooms, for instance, which are a staple of Russian cuisine, are prone to absorbing Cesium 137, a radioactive element with a half-life of 30 years.