China has approved imports of a biotech corn manufactured by Syngenta, a Swiss seed company with North American headquarters in Minnetonka.

Syngenta announced Monday that China has formally granted a safety certificate and will accept Agrisure Viptera corn and its byproducts for animal feed and human consumption.

The seed was engineered to provide protection against a broad spectrum of above-ground corn pests, and U.S. authorities approved its use in 2010. Chinese approval took four years, although the corn was earlier accepted for import by Australia, New Zealand, Belarus, the European Union, Indonesia, Japan, Mexico and seven other countries, the company said.

China rejected several shipments that had traces of Viptera corn late last year, causing Cargill to sue Syngenta for $90 million in losses. Farmers in Minnesota and other corn-producing states also filed lawsuits, claiming that the corn should not have been marketed and grown in the U.S. until China, a major customer, had signed off on it. They said China's refusal last year contributed to an oversupply of corn that drove down domestic prices and cost producers more than $1.1 billion.

Reports surfaced last week that China had approved Viptera, but company officials declined to confirm them until they received official documentation. Attorneys for the farmers and a Cargill spokesman said last week that the lawsuits pertain to past losses and will continue.