Letter Sources

(1) 
2023 study (University of New Mexico) – https://pubs.acs.org/doi/pdf/10.1021/acsfoodscitech.2c00265 

Xuechen Zhu, Emily N. Alden, and Jeremy S. Edwards. "Using Pet Food as the Subject to Investigate the Effectiveness of Whole-Genome Sequencing in the Authentication of Highly Processed Complex Food." ACS Food Science & Technology. 2023 3 (1), 50-60

- Test detected DNA of undeclared ingredients in all tested pet food samples. (100%)

- Dog DNA found in 2 of the 6 tested pet foods.

(2)
Thixton, Susan. “Dog DNA Found in 2 Pet Foods.” Truth About Pet Food. April 25, 2023. https://truthaboutpetfood.com/dog-dna-found-in-2-dog-foods/

(3)
2020 Study (UC Davis) - https://pubmed.ncbi.nlm.nih.gov/32879524/  

Cox A, Defalque VE, Udenberg TJ, et al. "Detection of DNA from undeclared animal species in commercial canine and feline raw meat diets using qPCR." Canadian Veterinary Journal. 2020 Sep;61(9):977-984. 

- More than 60% of tested foods contained unlabeled species.

(4)
2019 Study (UC Davis) - https://pubmed.ncbi.nlm.nih.gov/30375199/ 

Fossati LA, Larsen JA, Villaverde C, Fascetti AJ. "Determination of mammalian DNA in commercial canine diets with uncommon and limited ingredients." Veterinary Medicine and Science. 2019 Feb;5(1):30-38. 

- 21 dog foods were analyzed; all of them (100%) contained unlabeled species.

(5)
2018 Study (North Carolina State & Centre for Clinical Veterinary Medicine) - https://pubmed.ncbi.nlm.nih.gov/29357847/  

Olivry T, Mueller RS. "Critically appraised topic on adverse food reactions of companion animals: discrepancies between ingredients and labeling in commercial pet foods." BMC Veterinary Research. 2018 Jan 22;14(1):24.

- Found ingredients that were not on the label in up to 83% of tested diets

(6)
2018 Study (University of Turin) - https://pubmed.ncbi.nlm.nih.gov/30208880/   

Pagani E, Soto Del Rio MLD, Dalmasso A, et al. "Cross-contamination in canine and feline dietetic limited-antigen wet diets." BMC Veterinary Research. 2018.

- Undeclared animal protein found in 54.5% of tested foods

(7)
US Food & Drug Administration. “Final Response to Citizen Petition.” April 20, 2019. Truth About Pet Food. https://truthaboutpetfood.com/wp-content/uploads/2019/06/Final_Response_-_Letter_from_FDA_CVM_to_AssociationforTruthinPetFood_com.pdf 

(8)
US Food & Drug Administration. “FDA’s Regulation of Pet Food.” February 22, 2022. https://www.fda.gov/animal-veterinary/animal-health-literacy/fdas-regulation-pet-food#:~:text=However%2C%20the%20FDTruthfully%20labeled.  

(9)
United States Congress. “H.R.597 - PURR Act of 2025.” January 21, 2025. https://www.congress.gov/bill/119th-congress/house-bill/597/text 

(10)
Kerwin, Nicole. “PURR Act of 2025 sparks concerns for AAFCO." Pet Food Industry Magazine. February 24, 2025. https://www.petfoodindustry.com/safety-quality/pet-food-regulations/news/15738121/purr-act-of-2025-sparks-concerns-for-aafco

(11)
Grimm, David. “What if dogs had never been domesticated?” CNN. October 10, 2022. https://www.cnn.com/audio/podcasts/downside-up/episodes/e6cdd05d-6eec-491d-90b9-af2601443d17