Assessment of adulteration in the composition of dog food based on DNA identification by real-time PCR

Abstract

In a situation where the market of ready-made pet foods is the fastest growing in Europe, dog caregivers show some concerns about the use of ready-made products. Although pet food labels must be detailed and should inform about ingredients, mislabeling is an increasingly growing problem in the pet food industry. In an increasing number of studies, species undeclared by pet food producers are detected. This is especially important when using pet foods as an elimination diet in the diagnosis of adverse food reactions (AFR), as it interferes with the correct diagnosis. Therefore the aim of this study was to assess adulteration in the composition of complete commercial dry dog foods based on chicken DNA and pork DNA identification using the real-time PCR method. The study was conducted to determine whether dry over the counter foods (OTC) are a reliable alternative to veterinary therapeutic diets in the diagnosis and long-term therapy of AFR. The material consisted of 29 dry dog foods, some of which were labeled by the producers as hypoallergenic or mono-protein. Our research has shown that both mono-protein and hypoallergenic foods contain undeclared sources of animal proteins with lower economic value. In our study, 65 % of the dog foods contained undeclared chicken DNA, while 41 % – undeclared pork DNA. These results shown that both mono-protein and hypoallergenic dry dog foods should not be used in the diagnosis and long-term therapy of AFR in dogs with food allergies, as they may interfere with the effectiveness of the therapy, giving false negative results.