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Could your feed be contaminated with toxic heavy metals?

March 12, 2024
Could your feed be contaminated with toxic heavy metals?

Understanding contamination risk in feed and ingredients

There is growing awareness of the presence of trace heavy metals in the feed industry and their potential impacts on animal and human health.

Trace metals are naturally occurring elements, used in many industries and needed for regular body function in animals and humans. Zinc, iron and copper, for example, are essential in trace amounts. However, they can be toxic even at moderately elevated levels, and heavy metal poisoning occurs when too much of a particular metal is absorbed by the body. Mercury, lead, cadmium and arsenic are the most common metals to cause exposure at toxic levels.

The general population can be exposed to heavy metal contaminants through drinking water, dust, and fumes and from a variety of food sources (Atafar et al., 2010). Toxic heavy metals can be transferred into edible animal products such as meat, milk and eggs, and thus be passed into the human food chain. High levels of exposure to these compounds in humans can be toxic, with many having carcinogenic properties.

The buildup of heavy metals within animal protein sources can be attributed to the contamination of certain feed ingredients (Vremane et al., 1986; Spragg, 2008), with the potential for contamination originating from:

  • Exposure to groundwater and soil with high levels of heavy metals during crop production (transfer into plant material)
  • Bioaccumulation higher along the food chain (e.g., mercury in carnivores)
  • Raw material processing (e.g., for inorganic mineral extraction and recycling)
  • Cross-contamination during processing or transport, or in the feed mill

Understanding the risks within the feed industry

The past decade has seen growing scrutiny regarding the potential for heavy metal contamination in animal feeds. This is due to a number of high-profile food safety alerts. For example, in both 2020 and 2021, batches of dog foods from Europe were found to contain excessive levels of cadmium, and inorganic mineral sources destined for the feed industry are often reported by the European Food Safety Authority (EFSA) in the RASFF (Rapid Alert System for Food and Feed) Portal.

Other parts of the world, however, do not have such advanced monitoring or alert systems, and much of the risk may be missed or underestimated.

The Alltech 2023 Asia-Pacific Toxic Heavy Metal Survey

An ongoing effort to quantify the risk of toxic heavy metals to the feed industry has been carried out by Alltech in the Asia-Pacific region. Alltech initiated the survey in 2010 and has issued nine comprehensive reports so far, which have become essential benchmarks for assessing contamination risks in animal feed and trace minerals.

The survey analyzed 735 samples collected from 12 countries across the Asia-Pacific region, bringing the total number of samples analyzed to over 7,000 since the survey was launched in 2010.

Consistent with previous years, the survey evaluated lead, arsenic and cadmium levels, applying the European Union’s maximum allowable thresholds to determine contamination risks. The analysis encompassed complete feed, premix, and inorganic and organic trace mineral samples, spanning various agricultural categories including pig, poultry, ruminant, aquaculture and pet.

When completed, the survey revealed a contamination level of 14% across all these Asia-Pacific samples, with analysis showing that significant contamination was found in both organic trace mineral and inorganic mineral sources.

The survey highlighted that poultry premix exhibited the highest contamination levels at 13%, followed by aquaculture (9%) and ruminant premix samples (8%). In complete feed, swine diets demonstrated the highest contamination at 14%, followed by ruminant (9%) and poultry (5%). Certain samples displayed heavy metal levels surpassing EU regulations.

The collective results of all Alltech Asia-Pacific Toxic Heavy Metal Surveys since 2010 have revealed a persistent risk of elevated contamination in Asia-Pacific samples, with an average rate of 19%. This indicates serious and ongoing risks to both animal health and the safety of the entire food chain.

Managing feed contamination risk with reputable suppliers

To reduce the risk, it is imperative that feed and animal companies source their trace minerals from reputable sources. This involves working with companies that have robust quality systems, such as the Alltech Q+™ program, that focus on product safety, consistency and traceability for high-risk materials such as mineral sources. If we can reduce the risk of heavy metal contaminants entering the food chain, that will have flow-on effects to the human food chain.

For more information about the survey, please contact your local Alltech representative or email

About the author: 

Tara Tiller is the global project manager of corporate accounts and companion animals for Alltech. In this role, she oversees the growth of Alltech's pet and equine business as a member of the company's larger companion animal team.

Tara first joined Alltech as its quality assurance manager for the Asia-Pacific region. In that role, which was based in Thailand, she led the establishment of production facilities in Thailand, China, India and Vietnam and traveled extensively across Asia. She subsequently joined Alltech’s Mineral Management division, where she provided technical support and offered consultations, both internally and externally, across Asia-Pacific on trace mineral nutrition, with a focus on Alltech’s organic trace mineral range.

In 2018, Tara was named Alltech's global project manager. That role, which was based in Bangkok, combined her previous technical support responsibilities with the management of Alltech’s mineral projects and programs globally. In her current position on the company's companion animal team, she continues to develop and promote solutions and services related to mineral management.

Tara received a degree in animal science and aquaculture from the University of Tasmania in Australia.