A group of researchers in Taiwan identified a variety of undeclared species in cat foods available in the local market. The team published their results in the journal Bioinformatics and Genomics.
Undeclared animal species in pet food pose both health and ethical concerns. Some pets may be allergic to undeclared species, such as cattle or chicken. Pet owners themselves may object to the presence of tissues of certain animals in the food of their dogs and cats. For example, having pork in pet food can be problematic for Jewish or Muslim pet owners, just as beef can be an issue for Hindu pet owners. For ecologically conscious pet owners, silky sharks and other endangered species in pet formulations pose ethical problems.
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“To address this issue, we used DNA barcoding, a very effective identification method that can be applied to even highly processed products,” the researchers wrote.
Scientists used genetic analysis to observe a specific mitochondrial RNA gene as a marker to distinguish species. The team looked at 138 canned cat food products from 62 brands purchased from Taiwanese retailers.
“We found that the majority of mislabeling incidents were related to the substitution of tuna with other species,” they wrote. “Additionally, our metabarcoding revealed that multiple undeclared ingredients were present in all analyzed canned products. One product contained CITES Appendix II-listed shortfin mako shark (Isurus oxyrinchus). Overall, we discovered a mislabel rate of at least 28.99%.”
Undeclared species found in cat food
Nine of the cat foods were categorized as uncertain, while 89 were deemed correctly labeled. However, the researchers considered the remaining 40 products to be mislabeled. In these cases, either the genetically identified species is not included in the ingredient deck or is not the expected animal based on the declared ingredients.
Overall, the scientists identified 38 species that were not included in their respective labels.
- 24 fish
- two chickens (chicken and turkey)
- three animals (sheep/goat, cow, and deer)
- a reptile (softshell turtle)
- three crustaceans
- five mollusks
Although some of these animals clearly should not be included in the formulations, others may appear because the common names for the species are not always standardized in the pet food market in Taiwan.
“Unlike in the European Union and the USA, where there are official standardized lists of vernacular names for species used in foods and their corresponding scientific ones,” the scientists wrote. “Taiwanese authorities do not publish common lists of vernacular names used in the food industry…Instead, many ‘umbrella’ terms are used in the Taiwanese market.”
For example, for Taiwanese customers, a fish represented by a character is red sea bream (Pagrus major), but the same character can refer to other marine fishes in the family Lutjanidae, commonly referred to a snappers in English.
Considering other fish, previous studies have found evidence of endangered shark species in cat food. However, this study found only the endangered shortfin mako shark (Isurus oxyrinchus) in a sample.
Endangered species, allergens and religiously forbidden animals can cause many problems for pet food manufacturers when these creatures are included in recipes without being declared on the label.
