More than 350 people across 32 prefectures in Japan fell sick after eating food manufactured by a food company that has been alleged to have been selling tainted frozen food products.

The products have been earlier recalled in December due to possible pesticide contamination.

Kyodo News said on Monday health and state officials are investigating if the food were from Aqlifoods Co., a subsidiary of Maruha Nichiro Holdings Inc. The company in December said that some of its frozen food products were tainted with malathion.

Malathion is a type of insecticide, a product used to kill or control bugs. Poisoning may occur if a person swallows it, handles the product without gloves, or fail to wash hands soon after exposure. Significant amounts are absorbed through the skin unless proper precautions are taken.

The seafood company recalled more than 6.4 million packages of its products after receiving buyer complaints of around 455,000 phone calls that its products smelled of gasoline or engine oil.

Internal investigation showed all the products were produced at a plant in Gunma Prefecture. For some unknown reason, the insecticide carbophos made its way into the products.

Aqlifoods was able to recover around 1.11 million products, but this represented only 17 per cent of the entirety that was distributed to the market.

Among the products recalled included frozen pizza, croquets and Japanese pelmeni or Gedza.

The company believed the pesticide was intentionally added into products.

Malathion is used for agricultural purposes to kill and control insects on crops and in gardens. It is also used in government programs to kill mosquitos in large outdoor areas.

Malathion may also be found in certain products to kill head lice.