USDA FDC ingredient nutrient database

USDA FoodData Central (FDC) is designed for human nutrition, which creates specific gaps for pet food formulation — confirmed by the project's FDC probe dataset (usda_fdc_petfood_ingredients_20260718.json, 77 common pet-food ingredients checked against FDC SR Legacy/Foundation on 2026-07-18): 60 ingredients matched FDC entries (10 more later supplemented from Feedipedia), while 7 rendered/processed pet-food staples — chicken meal, lamb meal, turkey meal, salmon meal, mutton tallow, menhaden (raw), potato protein — returned no match, with the dataset noting verbatim: 'no matching SR Legacy/Foundation entry in FDC (human-food database); typical rendered/processed pet-food ingredient not covered'. Moisture structure differs sharply between the two worlds: FDC's raw human-food meats are high-moisture (e.g., 'Chicken, broiler, meat only, raw' = 75.5 g water/100 g), while the rendered meals used in pet food (not covered by FDC) are dry products — FDC's nearest analogue entries such as 'Soy meal, defatted, raw' sit at 6.94 g water/100 g. All FDC nutrient values are per 100 g edible portion. Energy is the other mismatch: pet food metabolizable energy uses AAFCO PF9's Modified Atwater formula, ME (kcal/kg) = 10[(3.5 × CP) + (8.5 × CF) + (3.5 × NFE)] (AAFCO 2024 Model Regulations), not FDC's human-oriented energy factors. For nutrient targets, formulators work from NRC's Nutrient Requirements of Dogs and Cats — the scientific basis of the AAFCO profiles (Dzanis, J. Nutr. 124:2535S-2539S, 1994) — rather than from FDC. Earlier unsourced specifics (a '5-10% vs 60-80%' moisture range for rendered meals, the 'N×6.25' protein-conversion claim, and 'most professional formulators use NRC 2006 plus proprietary databases') were removed or replaced with the dataset-verified statements above.