Commercially sold meat products were found to have been mislabeled, either accidentally due to cross-contamination or possibly for economic gain, according to findings from a small research study conducted by Chapman University’s Food Science Program.

In a study on identification of species found in ground meat products, 48 samples were analyzed and 10 were found to be mislabeled, according to the study. Lead researcher and assistant professor of food science at Chapman Rosalee Hellberg said a range of samples were taken from different outlets including 17 samples from supermarkets, 12 from a local butcher, and 19 from online retailers. She said the goal was to focus on collecting a variety of meat products from different retail sources.

A total of 48 fresh and frozen ground meat products representing a variety of species were collected for the research and tested using a combination of DNA barcoding and real-time polymerase chain reaction (PCR). Of those 10, nine were found to have additional meat species and one sample was mislabeled in its entirety.

Hellberg said all nine samples of ground beef that were tested were found to be correctly labeled.

Additionally, horsemeat was detected in two of the samples. One of the samples containing horse was labeled as ground bison and the other as ground lamb meat. Both had been purchased from two different online specialty meat distributors.

The sample labeled as ground bison had a top match for American elk, but analysis also revealed the presence of beef, pork, and horse. The sample labeled as ground lamb was identified as lamb/sheep, but analysis also revealed the presence of pork and horse.

North American Meat Institute president and chief executive officer Barry Carpenter explained commercial horse slaughter is no longer allowed in the U.S., but could occur if the meat is intended for personal consumption only. A horse owner could pay a slaughter establishment to “custom” or privately slaughter a horse and process its meat to be consumed by his or her family. That plant may also sell other meat processed under inspection into the commercial market.

“Such a circumstance could result in inadvertent co-mingling and sensitive DNA testing could find equine DNA in other meat processed at the same location,” Carpenter said in a statement.

The study speculates that the presence of multiple species commonly found in ground meats suggests the possibility of cross-contamination at the processing facility. Unintentional mislabeling may occur when several species are ground on the same manufacturing equipment, without proper cleaning in between samples. Another trend observed in the study indicates the possibility of lower-cost species being intentionally mixed in with higher-cost species for economic gain.

Overall, mislabeling was found to be most common in products purchased from online specialty meat distributors (versus supermarkets), which showed a 35% rate of mislabeling and included products labeled as black bear and yak burgers.

Hellberg said noted that only one of the supermarket products we tested was found to be mislabeled.  When asked whether it was ground at the retail level, she said “based on the product information, it appears to have been ground by the supermarket chain.”

Max Rothschild, animal science professor at Iowa State University, noted cross-contamination is a possible problem and fraud could also play a significant role in game meats. In general, food that is sold is as its advertised, but on occasion that isn’t the case, as shown through this study.

DNA tests can be based on unique characteristics of different species, Rothschild added, and PCR testing is very sensitive and can accurately determine whether you’re getting the product you’ve paid for, he said.

Game meats represent an important specialty market in the United States with an estimate value of $39 billion. According to the U.S. Food and Drug Administration (FDA), game meats are defined as exotic meats, animals and birds, which are not in the Meat and Poultry Act. Game meats produced in the United States are regulated by the U.S. Department of Agriculture, while game meats imported into the U.S. are regulated by the Food and Drug Administration.

Carpenter noted the vast majority of U.S. meat and poultry is processed in plants that handle one species of livestock or poultry. “USDA monitoring shows that U.S. meat and poultry products, with very rare exceptions, are exactly what the packaging says they are,” he said.

“Even if the mislabeling was accidental or due to cross-contamination, it is important for products to be accurately labeled,” Hellberg said. “Besides the legal requirements for accurate labeling, there are religious concerns and food safety issues associated with mislabeling of meat products.”