title: Detection of undeclared animal by-products in commercial canine canned foods: Comparative analyses by ELISA and PCR-RFLP coupled with slab gel electrophoresis or capillary gel electrophoresis.
abstract: BACKGROUND
  The potential presence of undeclared animal by-products in pet foods is not subject to routine examination. Previously published methods for species-based identification of animal by-products have not been used routinely owing to inconsistent results. The present study evaluated the utility of several approaches for accurate identification of animal by-products in 11 commercial brands of canine canned foods.
  
  
  RESULTS
  Canine canned foods from several countries were analysed by ELISA, PCR-RFLP coupled with slab-gel electrophoresis (SGE) and capillary gel electrophoresis (CGE) to test for evidence of by-products derived from cattle, chicken, sheep or pig. While CGE-based analysis detected all (24) animal-derived by-products that were reported for the 11 test samples, SGE and ELISA detected only 22/24 (92%) and 14/24 (58%) of labelled by-products, respectively. In addition, undeclared animal by-products were found using all three analytical approaches with CGE detecting more positives (19) than SGE (17) or ELISA (5).
  
  
  CONCLUSIONS
  Significant disparities were evident between the labelled contents and the detected content of animal by-products. CGE-based testing for PCR products appears to provide greater sensitivity and accuracy than either SGE or ELISA-based methods. As testing of commercial products becomes more reliable and mainstream, manufacturers will need to develop more thorough and accurate labelling protocols.
authors.affiliation: Graduate Institute of Microbiology and Public Health, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Ming-Kun
authors.initials: MK
authors.lastname: Hsieh
authors.affiliation: Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Pei-Yin
authors.initials: PY
authors.lastname: Shih
authors.affiliation: Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Chia-Fong
authors.initials: CF
authors.lastname: Wei
authors.affiliation: Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL, 32610, USA.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Vickroy
authors.affiliation: Department of Veterinary Medicine, College of Veterinary Medicine, National Chung Hsing University, Taichung, 402, Taiwan.
authors.forename: Chi-Chung
authors.initials: CC
authors.lastname: Chou
mesh_terms: D000821:Animal Feed / Q000032:analysis*; D000818:Animals; D004285:Dogs; D004586:Electrophoresis / Q000379:methods / Q000662:veterinary*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary*; D016133:Polymerase Chain Reaction / Q000379:methods / Q000662:veterinary*; D012150:Polymorphism, Restriction Fragment Length; D013045:Species Specificity
keywords: canine canned food; capillary gel electrophoresis (CGE); enzyme-linked immuno-sorbent assay (ELISA); polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP); slab-gel electrophoresis (SGE); vegan bone treat