U of G Conducts First-Ever Sausage Mislabelling Study
by Deirdre Healey
Using cutting-edge DNA-based technology, University of Guelph researchers have conducted the first-ever Canadian study examining sausage mislabelling.
The researchers found mislabelling and cross-species contamination of meat ingredients in 20 per cent of the sausage samples selected from grocery stores across the country.
“This study now provides us with a baseline that we can use when working with meat processors to help ensure we have a high quality and transparent food supply,” said Prof. Robert Hanner, who worked on the study with a team of researchers.
Published this week in Food Control, the study revealed a majority of the mislabelling occurred with sausage meat that was substituted with another type of meat. Some sausages labelled as beef also contained pork. Others labelled as chicken also contained turkey and one pork sausage sample contained horsemeat.
The study, which was funded by the Canadian Food Inspection Agency, involved sausage packages labelled as containing only one type of meat.
The team of researchers used DNA barcoding along with digital PCR technology to determine which meats were in the sausage samples.
Developed at U of G, DNA barcoding allows scientists to identify species of organisms using a short standardized region of their DNA.
“There is DNA in nearly every cell of every organism so barcoding can be applied to products such as ground meats that would be difficult to identify with other means,” said Hanner. “In this study, barcoding was used to identify the dominant meat type in the sausage samples.”
Digital PCR technology can be used to quantify the DNA of a particular target species. Tests using this technology were developed at U of G for beef, pork, chicken and turkey which allowed the researchers to assess the proportions of these meats in the sausage samples. Another PCR test was used by the researchers to detect horsemeat. This test only indicated the presence of horsemeat and not the quantity.
For beef, pork, chicken and turkey sausages, products were considered “contaminated” when more than 1 per cent of another meat was detected. This ruled out trace amounts that might have resulted from incomplete cleaning of processing equipment.
Findings revealed that five out of 15 sausage packages listed as turkey were entirely chicken.
Out of 27 beef sausage packages tested, seven samples also contained pork. Among 20 chicken sausage packages, four also contained turkey and one contained beef. And of the 38 pork sausage packages tested, two contained beef and one contained horsemeat.
Having more than one meat type in sausages labelled as a single meat is against food labelling regulations because consumers may be buying these products because of certain health issues, such as allergies, or lifestyle choices, such as not eating pork, said Hanner.
Unknown contaminants may also allow for the transfer of food pathogens, he added.
“When there is a recall on a certain type of meat, we may miss it if it is present in a sausage product, but not indicated on the label.”
Hanner, the associate director of the Canadian Barcode of Life Network and a professor at the U of G-based Biodiversity Institute of Ontario, said the reasons behind the meat contamination could reflect human error or economic motivations.
“This study demonstrates that the technology is capable of monitoring the industry in a way we were never able to do before and is just one example of how DNA testing is becoming a standard for food ingredient authentication.”