Duck Jerky

⚪ Formulation signal: soybean meal is concentrated plant protein used to raise the crude protein number on the guaranteed analysis without meat. The protein percentage on a label does not distinguish source, so a food can advertise strong protein while much of it is plant-derived and lower in the amino acids dogs actually need. Soy is also a common allergen and usually a GMO, glyphosate-treated crop. Matters most in the top five.

⚪ Mechanistic: sorbitol is a sugar alcohol used as a sweetener and humectant. Unlike xylitol — which is genuinely dangerous to dogs — sorbitol is not toxic, and conflating the two is a common error. The practical issue is that sugar alcohols are poorly absorbed and draw water into the gut, so meaningful amounts cause loose stools and gas. Present in small amounts in soft treats, it's a minor concern rather than a hazard.

The in vitro evidence is real and specific. Mamur et al. (Toxicology in Vitro, 2010) exposed human lymphocytes to potassium sorbate and found significant chromosomal aberrations at 500-1000 µg/ml, elevated sister-chromatid exchanges from 125 µg/ml, and DNA strand breaks at every concentration tested. ⚖️ But the in vivo picture does not follow it. EFSA's 2015 re-evaluation reviewed exactly these findings, concluded that live-animal studies did NOT confirm genotoxicity at realistic exposure, and maintained an acceptable daily intake of 3 mg/kg body weight. The concentrations used in those cell studies are in the 0.5-2 mM range, which dietary intake doesn't reach — potassium sorbate is metabolised much like a fatty acid. There is one more specific concern worth knowing: potassium sorbate reacting with ASCORBIC ACID in the presence of an IRON salt produces mutagenic decomposition products. Pet foods routinely contain all three. That interaction is a better reason for caution than the raw cell data. Our position: a preference against, not a demonstrated harm — and stronger where vitamin C and an iron source appear on the same label.