Hundreds of people fell sick across Japan after eating frozen food that may have been tainted with a pesticide, AP reported. Food maker Maruha Nichiro Holdings used full-page ads in major newspapers Wednesday apologizing and warning consumers not to eat any of the tainted food, including pizza, croquettes and pancakes manufactured at a factory in Gunma Prefecture, north of Tokyo.The company began recalling 6.4 million packages of various frozen foods on Dec. 29, saying it found some were tainted by high levels of malathion, a pesticide.Maruha has received hundreds of thousands of calls about the problem."The products will have a strong smell and eating them may cause vomiting and stomach pain," it said in the notice, which included 51 color photos of the problem products.The health ministry said it had confirmed 556 people suffering such symptoms after eating those products as of late Tuesday. In a notice on its website, it ordered Maruha Nichiro to recall all potentially affected products and to be forthright in informing the public about the situation.