An employee at an Aqlifoods Co. factory at the center of a food-poisoning scandal was arrested in Gunma Prefecture on Saturday for allegedly obstructing the firm’s business by tainting frozen food with pesticide.

The man was identified as contract worker Toshiki Abe, 49, of Oizumi, Gunma. He was taken into custody in Saitama Prefecture on Friday and interrogated Saturday morning, sources said.

Abe denied the charge and was quoted by police as saying he “doesn’t remember.”

According to the police, Abe, who engaged in pizza production, is suspected of having contaminated frozen foods on four occasions at the plant between roughly Oct. 3 and 7. He started working at the plant in October 2005.

More than 2,800 people across the country who ate frozen products produced at the plant, including pizzas, croquettes and fried chicken, reported they fell ill. Police suspect the pesticide sickened some of them.

According to officials of the Maruha Nichiro Holdings Inc. subsidiary, the pesticide, malathion, is not used in the plant, which led police to suspect the food was intentionally contaminated.

Prompted by customer complaints about an unusual odor in some of its frozen food products at the end of last year, Aqlifoods conducted tests and detected malathion in nine samples of seven different varieties of products that were produced in October and November.

The products came from separate production lines at the plant and were shipped after they were packaged in the same room. No holes or breaches were found in the packages.

Malathion is a yellow-colored organic phosphorus pesticide used to kill harmful insects such as spider mites and ant cows. Its toxicity for humans is relatively low as it breaks down quickly in the body, but it causes diarrhea and nauseousness after ingestion.

Maruha Nichiro has recalled 6.4 million packages of products produced at the plant. By Tuesday, the company said it had collected 85.9 percent of the packages that had been distributed to wholesalers and outlets