If it looks like a duck…quacks like a duck…then it must be safe to use in pet food.
Wikipedia terms the ‘Duck Test’ as a “humorous term for a form of abductive reasoning”. ‘If it walks like a duck, and quacks like a duck, then it probably is a duck.’
The FDA Duck Test is a not so humorous method for approval of risky foods and illegal pet food ingredients. ‘If it looks similar to legal ingredients, analyzes similar to legal ingredients, then it must be legal ingredients.’
The official term is “substantial equivalence”. It is commonly used when comparing GMO foods to non-GMO foods. Despite significant amounts of research proving risks of GMO food, the FDA believes (as example) GMO corn is the ‘substantial equivalence’ of non-GMO corn. GMO corn looks like regular corn, tastes like regular corn, so GMO corn must be the substantial equivalent of regular corn. Substantial equivalence is explained as “if a new food is found to be substantially equivalent in composition and nutritional characteristics to an existing food, it can be regarded as safe as the conventional food.”
This same attitude – substantial equivalence (or the Duck Test) – is FDA’s attitude towards rendered diseased or dead non-slaughtered animals in pet food. FDA’s Duck Test: ‘Illegal rendered material sourced from diseased, dead, rotting, putrid animal sources, have equivalent composition and nutritional characteristics to legal rendered material sourced from USDA inspected and approved animal sources, so illegal pet food ingredients must be safe for pets to consume.’
Look at “typical analysis” of chicken meal and chicken by-product meal provided by Dar-Pro (rendering company):
[alaya_one_half]Chicken Meal
Crude Protein: 63%
Crude Fat: 12%
Crude Fiber: 2.5%
Moisture: 4.5%[/alaya_one_half][alaya_one_half_last]Chicken By-Product Meal
Crude Protein: 65%
Crude Fat: 12.5%
Crude Fiber: 2.5%
Moisture: 4.5%[/alaya_one_half_last]
As you can see, the typical crude analysis of a pet food ingredient that is required to be sourced from slaughtered animals (chicken meal) is almost identical to the typical crude analysis of a pet food ingredient that is allowed to be sourced from diseased, dead, rotting, putrid non-slaughtered animal sources (chicken by-product meal).
How can this be? How could USDA inspected and approved ingredients analyze the same as illegal USDA rejected/condemned or dead non-slaughtered ingredients? The answer is ‘crude’.
Pet foods and pet food ingredients are analyzed by ‘crude’ methods. If you notice on your pet food bag or can it provides all nutrient information as ‘crude’ – ‘crude protein’, ‘crude fat’, and ‘crude fiber’. ‘Crude’ means general, basic, and/or simplistic analysis.
The reason they analyze the same is because the system of analysis is set up as simple (crude). The system of crude analysis is NOT designed to highlight quality of ingredients; the system of crude analysis is designed to keep consumers in the dark to the true quality of some pet food ingredients.
If it walks like a duck…
Illegal pet food ingredients – those that are sourced from dead non-slaughtered or diseased animals remain illegal. It doesn’t matter if they passed the FDA Duck Test.
Wishing you and your pet(s) the best,
Susan Thixton
Pet Food Safety Advocate
Author Buyer Beware, Co-Author Dinner PAWsible
TruthaboutPetFood.com
Association for Truth in Pet Food
What’s in Your Pet’s Food?
Is your dog or cat eating risk ingredients? Chinese imports? Petsumer Report tells the ‘rest of the story’ on over 4000 cat foods, dog foods, and pet treats. 30 Day Satisfaction Guarantee. www.PetsumerReport.com
The 2016 List
Susan’s List of trusted pet foods. Click Here
Have you read Buyer Beware? Click Here
Cooking for pets made easy, Dinner PAWsible
Find Healthy Pet Foods in Your Area Click Here

Anthony Hepton
May 11, 2016 at 4:25 pm
The problem is obvious, crude analysis measures major constituents like protein , fat and carbohydrates, but doesn’t even consider bio availability. other factors such as contaminants are not even entered into the equation. The presence of toxins, which have been shown to cause disease are not evaluated, so we can have a live duck or a dead duck. The pet food industry with the help of FDA has been serving us DEAD DUCK for far to long, it’s time for a change.
Peter
May 11, 2016 at 7:10 pm
“Crude protein,” often also refers to ingredients in their original (and pre-rendered) state, and, as you discuss above, with little or no information about the source of that protein.
Sherrie Ashenbremer
May 16, 2016 at 8:46 am
Again our government is screwing us over