Toxic heavy metals detected in imported pet foods sold in China

CHINA – Dog and cat foods imported into China have been found to contain toxic heavy metals at levels that may pose significant health risks to pets, according to a new study by researchers at Huazhong Agricultural University in Wuhan.

In an alarming discovery, the team analysed 93 imported pet food products, 45 for cats and 48 for dogs, manufactured between 2021 and 2022 in the United States, Spain, Thailand, Germany, and New Zealand. 

The samples were purchased from retail stores in Beijing, Shenzhen, and Wuhan. Notably, none of the products were made in China.

The researchers tested for five toxic metals: lead (Pb), cadmium (Cd), chromium (Cr), mercury (Hg), and arsenic (As). Using atomic absorption and fluorescence spectrometry, they found Cr and As in every single sample, and Hg in 97% of them. 

Dry food products, particularly those made in the U.S. and Europe, were more frequently contaminated and had higher concentrations of the most harmful metals.

“As the long-term accumulation of toxic metals in food poses significant health risks to pets, there is a growing concern among people regarding toxic metal contamination in pet food,” the researchers wrote in Nature’s Scientific Reports.

The findings reveal that 26.88% of the pet foods tested exceeded China’s regulatory limit for chromium, with one sample containing 15.47 mg/kg. Lead surpassed the safety threshold in 8.60% of all samples, with one reaching 5.80 mg/kg. 

While canned foods were within legal limits, dry foods showed consistently higher contamination, especially with Cr, Hg, and As.

In fact, the study noted that all dry food samples contained at least two toxic metals, and nearly half had three. Some even contained all five. Cr and As were most prevalent in cat foods, while dog foods showed a 100% detection rate for both Cr and Hg.

Potential sources of contamination include commonly used ingredients like meat and bone meal, fish meal, and grains, which may accumulate metals from polluted environments. 

The researchers also pointed to processing techniques such as baking and extrusion, and food packaging materials, particularly plastics, as additional contamination risks.

The study further assessed acute hazard index (aHI) values to evaluate short-term exposure risk, finding that Cr posed the most significant threat to both cats and dogs, followed by Pb and As. Lighter animals were shown to be more susceptible due to their smaller body mass.

“As natural components of the earth’s crust, the penetration of toxic metals is ubiquitous,” the study noted, highlighting the challenge of avoiding contamination in multi-ingredient pet foods.

The widespread co-contamination of Cr, Hg, and As raises concerns about their combined toxicological effects—an area that remains under-researched, particularly in pets.

The researchers warned that the cumulative impact of multiple metals may be more severe than exposure to each metal individually.

The findings underscore the urgent need for stricter international quality control standards in pet food manufacturing and greater scrutiny of imported products. 

As the demand for premium pet foods rises globally, so too does the importance of ensuring these products are safe for the animals they are intended to nourish.

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