A comprehensive DNA barcoding study of 138 canned cat food products in Taiwan has unveiled widespread mislabeling, posing potential risks to pet health, violating religious dietary laws, and threatening natural resource management.
Researchers utilized advanced DNA barcoding techniques to scrutinize the contents of these products, revealing significant discrepancies between labeled and actual ingredients. Their findings indicate that species substitution and the inclusion of undisclosed species are common issues in processed pet foods. Notably, the study found that tuna was frequently replaced with other species, and numerous undeclared ingredients were present across all samples tested. The overall mislabeling rate was found to be 28.99%.
The study, conducted by researchers Yu-Chun Wang, Shih-Hui Liu, Hsuan Ching Ho, Hsiao-Yin Su, and Chia-Hao Chang, focused on a short segment of the mitochondrial 16S rRNA gene using both Sanger and next-generation sequencing (NGS) methods. This approach enabled precise identification of species in various canned cat foods, highlighting the extent of misrepresentation in the Taiwanese pet food market.
The analysis covered 138 cans of cat food, which collectively listed 38 different ingredients derived from fish, poultry, livestock, reptiles, crustaceans, and mollusks. Of these, 89 products were accurately labeled, nine were uncertain, and 40 were mislabeled. Mislabeling occurred when the species identified through molecular analysis did not match the declared ingredients or were absent from the ingredient list.
A significant revelation was the frequent substitution of Thunnini fish for tuna. Thunnini encompasses several genera (Thunnus, Katsuwonus, Auxis, Euthynnus, and Allothunnus), but only Thunnus and Katsuwonus are legally recognized for commercial tuna products. The study found that Auxis and Euthynnus were often used instead, violating labeling laws.
With a mislabeling rate of nearly 29%, all products examined by NGS metabarcoding contained undeclared species, suggesting that mislabeling in the Taiwanese market is more extensive than previously understood. Additionally, the study found that nearly all fish used in the cat food samples were wild-caught rather than farmed.
The research underscores the need for more precise resource exploitation tracking through fishery product barcoding studies. The extensive use of Thunnini in cat foods, along with the discovery of an endangered shark species in one product, highlights the urgency of further DNA barcoding projects. Such efforts would not only protect pet owners and their pets but also contribute valuable data for better marine resource management.
The Serious Implications of Pet Food Mislabeling
Mislabeling pet food poses serious risks. Consumers may inadvertently handle food that conflicts with their cultural, spiritual, or medical dietary restrictions. For instance, although pig was not listed as an ingredient, the analysis detected its presence, posing issues for Muslim cat owners. Similarly, the identification of non-kosher shark species in some products presents problems for Jewish cat owners.
Undeclared ingredients also pose health risks to pets, particularly those with food allergies. The study noted the presence of beef and chicken—common allergens—in some products without proper labeling, raising concerns about cutaneous adverse food reactions (CAFRs) in cats.
The researchers call for increased investigations into pet food labeling to protect pets’ health, ensure consumers are accurately informed, and promote the sustainable use of fishery resources.
