Spate of mysterious poisonings that left 22 dogs dead may have been caused by contaminated horse meat - as pet owners are warned toxic food could still be on shelves

Authorities are investigating whether 22 dogs which died of liver failure in a mysterious mass poisoning ate contaminated horse meat.

Another 44 dogs were hospitalised in the eastern suburbs of Melbourne, Bairnsdale, Tralragon and on the Mornington Peninsula earlier this month.

Some have since developed severe liver disease.

In a statement released on July 30, Agriculture Victoria and PrimeSafe said tests had confirmed pet meat from sourced Maffra District Knackery contained a toxin found in native plants called indospicine.

A group of dogs died and 44 more were hospitalised throughout the eastern suburbs of Melbourne, Bairnsdale, Tralragon and the Mornington Peninsula (pictured: one of the poisoned dogs)

'Indospicine is a toxin found in native plants of the species across Australia, but the species that produces high levels of the toxin is found in northern Australia,' the organisations said.

'Indospicine has been previously shown to build up in the tissue of some grazing animals when they continue to eat these plants and dogs are especially sensitive to the toxin.

'Horse meat is emerging as the focus of the investigation into the indospicine toxin found in pet meat products. Indospicine is a toxin to which dogs are especially sensitive.  

PrimeSafe and Agriculture Victoria said they were aware of horses from the Northern Territory - where the Indigofera plant that contains indospicine is known to grow - that came to Victoria to be processed for pet meat.

They urged pet owners to not feed their pet meats sourced from Gippsland between 31 May and 3 July.

'All kinds of pet meat fitting that description should be considered at risk of indospicine contamination, due to the blending of pet meats, including products described as beef and kangaroo pet meat.' 

Authorities have said the meat could still be in circulation, as it is incredibly hard to identify all affected food products as the meat may be in a variety of items.

'Businesses and dog owners are encouraged to check the source of their pet meat. If unsure, owners are advised to contact their pet meat supplier to check where and when their pet meat was sourced. Some products will be labelled as Maffra District Knackery and Backman’s Greyhound Supplies,' they said. 

The Maffra District Knackery issued a recall of the meats earlier this month after a request from PrimeSafe. 

In a post on Facebook Maffra District Knackery joint owner Karen Backman said she had been left shattered by the dog deaths, but said they were seeking the scientific data that linked their food to indospicine.

'We are devastated that an exotic plant toxin from interstate in our pet meats has been linked to the unprecedented spate of dog illnesses and deaths in Victoria by the authorities,' she wrote.

'As dog lovers, as people, as parents, as grand parents we understand how much dogs mean to their human families. We are still totally shocked that toxins in animals we were told were originally bred for human consumption could harm dogs.

'While we welcome the animal health authority’s findings that the Australian plant toxin, indospicine, was the cause of the mystery severe liver disease we cannot yet comment on whether we agree with their ultimate conclusions that the toxin was in our meat and that toxin was what injured the dogs. 

'We are seeking the scientific data that links our meat to the toxin. We have not seen any data yet. Our scientific team will review the data when we get it.'