The two men were working in the northern city of Tangshan as inspectors for Mengniu, one of China's largest dairy companies, which has implemented strict new safety inspections, the China Youth Daily reported.

The attack occurred November 5 after inspector Li Zhongping had confronted an outside dairy supplier over a batch of milk he was selling that appeared not to confirm with new standards, it said.

'According to an initial analysis, this incident was triggered by (Li's) decision that this truck's milk was not in compliance', it quoted an unnamed Mengniu official as saying.

Mr Li and another inspector, Mr Zhang Liwei, were set on by a group of about five club-wielding men as they left work later that day.

Mr Li was badly beaten, suffering numerous injuries over his body, including fractured vertebra, and was in a coma for 'a long time', the paper said, without specifying Mr Li's current condition.

Neither victim could identify the milk supplier nor the attackers as both inspectors had only recently been rotated to Tangshan.

Police were investigating, the paper said.

China has ordered tightened safety inspections in the dairy industry nationwide after it emerged in September that milk supplies had been tainted with the industrical chemical melamine.

The tainted products have been blamed for killing at least four infants in China and sickening more than 50,000 others in one of the worst of a string of safety scandals involving Chinese-made products in recent years.

Middlemen who collect milk from dairy farms and sell it to large firms have been blamed for adding the melamine to try to make the milk appear to contain more protein than it actually did.

The incident sparked a massive recall of dairy products in China as well as bans, recalls, or safety warnings in several export markets. --AFP