Image copyright Getty Images Image caption What's in your meat?

One in five sausage samples from Canadian grocery stores tested by researchers contained meat that was not listed on the label.

Researchers from the University of Guelph tested 100 raw meat sausage samples labelled as being solely beef, pork, chicken or turkey.

They found that 20% of the samples contained meat other than marked on the ingredients, to varying degrees.

Five of the 15 sausages labelled as turkey were actually mostly chicken.

The DNA analysis indicated that 6% of the beef sausage samples also contained pork, that 20% of the chicken sausages contained turkey and 5% contained beef, and that 5% of the pork samples also contained beef.

One pork sausage also contained horse meat.

The research was published on 31 July in the Food Control journal and commissioned by Canada's food inspection agency.

The University of Guelph's Robert Hanner, who was one of the researchers, said that while food safety in Canada is generally high, the findings suggest "there are some gaps in the existing traceability systems".

The mislabelling could be a problem for people with allergies and could lead to products that contain pathogens not being fully recalled.

The findings will also be of concern for people who avoid pork for cultural or religious reasons.

"I think consumers should get what they pay for," Mr Hanner said.

The researchers say that several studies around the world have also reported substitution in meat products but this is the first time sausage products have been looked at in Canada.

Mr Hanner said it was not immediately clear how, why or when the mislabelled meat got into the sausages but the amounts meant it was "more than just residue on the grinder".

In 2013, the discovery of horsemeat in processed beef products sold in UK and European supermarkets led to product recalls and had politicians and consumers take a closer look at the food industry's supply chains there.

Mislabelled processed meat products were discovered in the UK, the Republic of Ireland, France, Norway, Austria, Switzerland, Sweden and Germany.