Beijing, Feb.8 : Chinese health monitoring authorities have recalled over 170 tons of milk powder during a ten -day nationwide crackdown on melamine-tainted dairy products.

According to the China Daily, two dairy companies in the country's Ningxia Hui autonomous region were closed for selling tainted milk powder on Saturday, while candies made with tainted milk powder were found in Jilin province on Sunday.

The Ningxia Tiantian Dairy Co Ltd and Ningxia Panda Dairy Co Ltd have been sealed after the raid.

A third company-the Ningxia Tiantian Dairy Co Ltd - is also under investigation for accepting and selling about 170 tons of milk powder - melamine-tainted products left over from the 2008 scandal that should have been destroyed.

Officials said that from July to November last year, the company repacked 164.75 tons of the affected powder in their own packages and sold it to five factories in the Inner Mongolia autonomous region, Fujian and Guangdong provinces.

About 72 tons of the milk powder have been recalled and seized and the authorities are tracking the rest of the tainted products.

Zhao Shuming, secretary-general of the Ningxia Dairy Industry Association, said: "Many small companies lack the technology to test melamine, an industrial chemical added to milk to boost false protein readings in quality tests."

"As a small company, the Tiantian dairy company doesn't have a machine to test melamine. Such a machine can cost up to 1 million yuan ($147,000). So many companies are just not able to check if the milk powder they buy is safe or not. But their repacking of the products is illegal," Zhao told China Daily yesterday.

Zhao said the latest findings have dealt a huge blow to the Ningxia dairy industry.