A meat contamination scare has spread to a fourth state, with a "distinctive" piece of metal found in pre-packed meat sold in a supermarket in South Australia.
Police said the latest find was in a packet of sausages bought at Woolworths at Gawler, north of Adelaide.
Similar pieces of metal, around six centimetres long, have also been found in meat and frozen products in other supermarkets in New South Wales, Western Australia and two in Queensland.
All five cases are believed to be linked and police have launched several avenues of inquiry, said Detective Superintendent Gayle Hogan of Queensland Police Service, which is heading the investigation.
"This is a complex investigation that covers a number of states and a number of different suppliers, a number of different distribution centres, different transport ... There's quite a number of different things to look at," Det Supt Hogan told reporters.
"The important thing here is for consumers to be vigilant in relation to the preparation of any product and if there is any contaminant there, to make sure that they report that."
All the metal objects were found as the products were being unpacked or cooked and none were ingested.
All the food was sold between January 5 and March 18 but police are not ruling out more cases coming to light.
"Our minds are open that there may be other things out there which is why we would like the public to be vigilant," Det Supt Hogan said.
But police were refusing to release further details for fear of copycats.
"That's another reason as a part of the investigation we keep information to ourselves because any copycat people could muddy the investigation and then we don't have control of what's going on," Det Supt Hogan said.
No threats had been received by a supermarket or by police, she said.
"As previously said, we don't believe the person is out to harm anybody but we believe the person is out to cause alarm."
Queensland Health's senior director of population health Dr Linda Selvey said the metal was large enough to be noticed before eating.
"The object is large enough that it has been detected before the products have been consumed, yet if somebody was intending to harm they could do something different."
Police say anyone finding a piece of metal in their food should return the object, the food product and packaging to the point of purchase.
They should also contact Crime Stoppers on 1800 333 000.