Synutra milk powder [file photo]

Official food tests have proven that a well-known Chinese baby formula is safe, following allegations that a five-month-old boy died and his twin sister was hospitalized after drinking it early this month.

Five samples of the same batch of Synutra milk powder manufactured by Qingdao-based Synutra International passed the bacteria tests ordered by the government of Duchang County in east China's Jiangxi Province yesterday.

The whole batch of Synutra milk powder sold in Duchang has been sealed and investigation is ongoing to find the cause of the food poisoning, the county government said on its website.

The baby named Jiang Jian died of multiple organ failures on January 8 after he was fed the formula milk. The baby soon showed symptoms of diarrhea and convulsion.

An earlier government report said the baby died of infant muggy syndrome which occurs when a baby gets too hot bundled up in a thick wrapper.

His twin sister Jiang Yunxin showed the same symptom but is in stable condition now.