Rat poison has been found in a jar of HiPP baby food, police in Austria have said, after a recall of the product from more than 1,000 Spar supermarkets in the country over safety fears.

Police in Burgenland said in a statement that a sample from one of the 190g (7oz) jars of carrots and potatoes baby food reported by a customer had tested positive for rat poison.

HiPP had said on Saturday it could not be ruled out that a dangerous substance had been introduced into the product, and that its carrots and potatoes jars may have been tampered with.

Consuming the contents of the jars could be life-threatening, HiPP said.

The police statement said the affected jars had a sticker with a red circle on the bottom of the jar and a lid that had already been opened or damaged or missing a safety seal, or had an unusual smell.

They said initial lab tests on similar jars seized by police in the Czech Republic and Slovakia showed the presence of a toxic substance. The statement gave no further details.

The police also said authorities in Austria had been warned about the risk after investigations in Germany. They provided no further details.

HiPP said on Saturday: “According to our current knowledge, this critical situation involves an external criminal interference that affects the Spar Austria distribution channel.”

HiPP was not immediately available for comment on Sunday.

A Spar spokesperson told Reuters on Saturday that the product recall was a precautionary measure and affected 1,500 stores in Austria, with no impact on outlets elsewhere.

Spar and HiPP advised customers not to consume the contents of the jars bought from Spar Austria. They said customers would receive a full refund on returned products.

Police advised customers to wash their hands thoroughly if they came into contact with a jar.