University of Guelph researchers found mislabelling and cross-species contamination of meat ingredients in 20% of the sausage samples.
Some sausages labelled as beef also contained pork. Others labelled as chicken also contained turkey and one pork sausage sample contained horsemeat.
DNA barcoding and ddPCR
100 raw meat sausage samples labelled as single meat species products (beef, pork, chicken or turkey) were collected from retail across Canada and surveyed for the presence of non-labelled species.
A total of 6% of beef sausages contained pork, 20% of chicken sausages contained turkey while 5% contained beef and 5% of pork sausages also contained beef.
The predominant meat species were determined using DNA barcoding and contaminant or unclaimed species were detected using digital droplet PCR (ddPCR) using species specific primers and probes. All samples were also tested for horsemeat using real-time PCR.
Samples were collected from Montreal (40), Toronto (25) and Calgary (35) and all sampling was between January 17 and February 25, 2016.
Ninety samples originated from Canada while five were imported from the US and another five were from unknown origin.
From 27 beef sausages, seven samples also contained pork. Two of these contained more than 5% pork.
From 20 chicken sausages, four contained turkey, two at more than 5%, and one sample contained beef at 1-5%.
Different pathogen testing
Two out of the 38 pork sausages were mixed with beef at 1-5%.
Researchers said the results were encouraging but even small amounts of undeclared species can have potential human health implications.
“For example, the presence of beef in one chicken and two pork products was unexpected as beef is a more expensive meat.
“This could mean that “waste” beef products, rework, or other non-conforming materials that may not otherwise be consumed are being introduced as a cheap addition to these sausage products. Alternatively, it could mean that insufficient cleaning between grinding of different meats is occurring.
“Either way this could represent a means for pathogens to enter the food supply as beef products, particularly by-product, would be subject to different screening, specifically screening for E. coli O157:H7. In the event of a recall, products where beef is present, but undeclared, would not be removed from sale, presenting another potential health risk.”
Five turkey sausage samples contained chicken as the predominant species.
Five turkey samples contained no turkey
A third of turkey products were found to be wholly substituted with chicken.
“The price of ground turkey in Canada for 2016 was more than that for ground chicken suggesting that these instances of substitution may be economically motivated or that a gross mislabelling event occurred during production or packaging. All these samples were produced in the same establishment but purchased in different cities.”
Five samples labelled as turkey sausage contained no turkey and one pork sample was found to contain horsemeat. The test only indicated the presence and not the quantity.
According to Canadian regulations, horse can be sold for human consumption but must be labelled on packages.
“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 Professor Robert Hanner.
Source: Food Control
“Complementary molecular methods detect undeclared species in sausage products at retail markets in Canada”
Authors: Amanda M. Naaum, Hanan R. Shehata, Shu Chen, Jiping Li, Nicole Tabujara, David Awmack, Cyril Lutze-Wallace, Robert Hanner