Detection of DNA from undeclared animal species in commercial elimination diets for dogs using PCR

Vet Dermatol. 2017 Aug;28(4):373-e86. doi: 10.1111/vde.12431. Epub 2017 Feb 28.


Background: Elimination diets are the gold standard for the diagnosis of adverse food reactions (AFR). A broad variety of commercial diets are available containing either hydrolysed protein or novel ingredients which claim to be suitable for elimination diets. Contamination may be one factor accounting for the failure of commercial elimination diet trials.

Hypothesis/objectives: To test commercial diets labelled as suitable for elimination diets for dogs, for DNA of animal origin other than that declared on the label.

Methods: Twelve commercial dry and tinned dog food products were investigated for DNA of animal origin (chicken, turkey, beef, mutton and pork) using PCR testing.

Results: In nine of 10 over-the-counter diets, DNA of one or more animal species other than declared on the label was identified. The DNA most frequently detected was derived from beef (n = 8) and pork (n = 6). Two hydrolysed diets only contained DNA of the declared animal source.

Conclusions and clinical importance: Over-the-counter "single protein diets" or canned meat products cannot be recommended for the diagnosis of dogs with AFR because contamination may cause the elimination diet to fail.

MeSH terms

  • Animal Feed / adverse effects
  • Animal Feed / analysis*
  • Animals
  • Cattle / genetics
  • Chickens / genetics
  • DNA / analysis*
  • DNA / genetics
  • Diet / veterinary
  • Dog Diseases / diagnosis*
  • Dogs
  • Food Hypersensitivity / diagnosis
  • Food Hypersensitivity / veterinary*
  • Real-Time Polymerase Chain Reaction / methods
  • Real-Time Polymerase Chain Reaction / veterinary*
  • Sheep / genetics
  • Swine / genetics
  • Turkeys / genetics


  • DNA