A Zhejiang province-based enterprise has been fined 1.4 million yuan ($225 481) for trading "zombie" papaya products, Qianjiang Evening News reported on Tuesday.

In a March raid, law enforcers seized 32.86 tons of frozen papaya pieces stored at a local warehouse in Ningbo city. The fruit products had been produced five to six years ago and expired more than two years ago, according to the report.

Investigators have discovered that cooperation between the Ningbo company and the warehouse dated back to before 2010.

Transaction records show the Ningbo company bought a total of 84.23 tons of papaya products from Hainan province and Guangxi Zhuang autonomous region in 2010 and 2011 and stored them at the facility.

A company based in Suzhou, Jiangsu province, and mainly engaged in the production of juice and jam bought a total of 34.22 tons of frozen papaya products from the Ningbo company between April and October 2010, says Wang Weijie, a local quality inspector.

Their most recent trading of expired papaya products happened in 2013. The Ningbo company sold two batches - five tons in January and 20 tons in April - to the Suzhou company, according to investigators.

Wang says many enterprises think frozen foods never expire, but that is false.

He added that law enforcers will step up inspections on frozen foods and urges enterprises to destroy or dispose by whatever harmless means food products that have expired or are near their expiration dates in a timely manner.