More than 300 people across Japan have fallen ill after eating frozen food products contaminated with pesticide.

Shoppers have reported vomiting, diarrhea and other symptoms of food poisoning after eating food produced at a plant in Gunma, north of Tokyo, according to surveys carried out by the Asahi Shimbun and other local media.

The plant, run by a subsidiary of the nation’s largest seafood firm Maruha Nichiro Holdings, is at the centre of the nation’s latest food poisoning scandal.

Japanese police have launched an investigation into the company after it revealed last month that some of its frozen food products were tainted with malathion, an agricultural chemical often used to kill aphid in corn and rice fields.