Parents in Austria have been warned that a popular brand of baby food has been contaminated with rat poison.

Police officers issued the warning after a jar of HiPP baby food tested positive for the toxic substance on Saturday. Officers did not initially say whether the jar had likely been contaminated deliberately, or by accident.

HiPP, which is headquartered in Switzerland, immediately responded by saying the contamination could be "life-threatening" and recalling its entire range of jarred purees on sale at all 1,500 Spar supermarket branches throughout Austria. Jars sold at branches of Eurospar, Interspar, and Maximarkt can also be returned for a full refund, the company added.

Police in the Burgenland region of eastern Austria raised the alarm after a customer in the regional capital, Eisenstadt, made a complaint about a 190-gram jar of carrot-and-potato baby food. Officers said the customer noticed the lid looked to have been tampered with and did not feed it to a child.

Officers told parents to be on the lookout for jars with damaged or loose lids, missing safety seals and unusual smells. They also said the jars could have a white sticker with a red circle on the bottom. People who have handled a potentially compromised jar should wash their hands thoroughly.

"Should you possess HiPP baby food with this marking or notice any irregularities: do not open it," officers warned. "Do not consume it under any circumstances or of fer it to a small child."

While it was not immediately clear whether the contamination was deliberate or accidental, HiPP said:"It cannot be ruled out that a hazardous substance was introduced ... due to external influence."

The company added on Saturday that "according to our current knowledge, this critical situation involves an external criminal interference that affects the Spar Austria distribution channel".

It said "further investigations are currently being conducted by the Burgenland State Criminal Police Office in cooperation with the Federal Criminal Police Office" and that customers should exercise "increased vigilance and prompt reporting of any suspicious observations".

Police officers in Germany, where HiPP has production facilities, are also understood to be investigating the possibility that jars have been deliberately contaminated.

Officers in the Czech Republic and Slovakia have also reported finding jars of baby food that have been spiked with a noxious substance.

A Spar spokesperson told Reuters on Saturday the recall of all HiPP baby food jars sold through its stores in Austria was largely precautionary, and that Spar stores outside the country were not thought to have been impacted.

The warnings and recalls only apply to HiPP's pureed baby food. The company's baby milk formula is not thought to have been affected.

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