Du et al. 2025 — Toxic metals in commercial cat and dog food, Chinese market
This study measured concentrations of Pb, Cd, Cr, Hg, and As in 93 imported cat and dog food products collected from the Chinese market (produced 2021-2022) and conducted a health risk assessment for pets. Flame AAS (Pb, Cd, Cr) and atomic fluorescence spectrometry (Hg, As) were used following dry ashing digestion. Cr and As were detected in all 93 samples; Hg was detected in 91. Cr had the highest concentrations of the five metals. Some samples exceeded Chinese Pet Feed Hygiene Standards (Announcement No. 20, 2018) for Pb (8.6% of samples) and Cr (26.88% of samples); other metals remained within limits. Dry food showed higher contamination rates and concentrations than canned food. Combined contamination (multiple metals simultaneously) was prevalent, with Cr + Hg + As the most common triad.
Key numbers
93 samples (45 cat food, 48 dog food; 79 dry, 14 canned). Pb: highest positive sample 5.80 mg/kg; contamination rate 10.75% (above LOQ 2 mg/kg). Cd: contamination rate 17.20% (above LOQ 0.20 mg/kg); max reported but not extracted here. Cr: detected in 100% of samples; highest 15.47 mg/kg; 26.88% exceeded Chinese standard. Hg: detected in 97.85% of samples. As: detected in 100% of samples. Chinese standard limits: Pb ≤5 mg/kg, Cd ≤0.5 mg/kg, Cr ≤5 mg/kg, Hg ≤0.1 mg/kg, As ≤4 mg/kg. LOD/LOQ reported per element in Table 1. Acute hazard index (aHI) calculated for cats and dogs; Cr poses highest aHI followed by Pb and As.
Methods (brief)
Dry ashing digestion. Pb, Cd, Cr by FAAS (ZEEnit 700P). Hg, As by AFS (AFS-8530). Recovery rates: Pb 105.28%, Cr 117.93%, Cd 102.52%, Hg 89.9%, As 107.6%. RSD 2.88-4.16%. No As speciation reported (total As only).
Implications
Certification: Pet food heavy metal data; Cr and As contamination at 100% detection rate. Pb exceedance at 8.6% of samples is notable for pet food context. Not directly applicable to HMT&C food certification (human food only) but documents supply chain contamination in animal food ingredients. Courses: Demonstrates multi-metal contamination patterns in commercial foods and the combined-contamination health risk assessment approach. App: Pet food matrix; not applicable to human food contamination profiling directly.