When consumers hear about foods that contain heavy metals, panic ensues because many heavy metals are toxic when consumed above safe levels.
In some cases, metal supplements that are not considered “heavy metals” may be added to certain foods, which may confuse consumers. This is why testing for heavy metals in food is a crucial part of your safety program. It ensures that the food consumers are eating is safe for consumption, but it also helps educate consumers on what is acceptable and what isn’t when it comes to the addition of metals in some foods.
In this article, we explain how to test food for heavy metals and cover the regulations involved.
Does the FDA Monitor Heavy Metals in Foods?
There has been quite an uptick in reports of heavy metals in food, such as recent news of lead in cinnamon.
However, the U.S. Food and Drug Administration (FDA) states explicitly that they do monitor levels of metals in foods. The FDA currently runs two tests for metals and other elements in food products, including the following:
- FDA Total Diet Study: This FDA program carefully monitors levels of approximately 800 different contaminants and nutrients in the average diet of U.S. citizens.
- FDA’s Toxic Elements in Food and Foodware; And Radionuclides in Food Compliance Program: This program is specifically designed to monitor foods and products used in the consumption of foods, such as ceramicware, for the presence of toxic elements and radionuclides.
The FDA also states that they conduct targeted sampling assignments to report potentially elevated levels of heavy metals or other toxic elements in certain foods.
It is also worth noting that dozens of third-party testing groups perform heavy metal testing as a regular part of their food safety testing practices to further ensure the safety of the consumable products currently on the market.
Which Heavy Metals in Food are Most Problematic?
While the term “heavy metals” is scientifically defined as any metallic element with high density, the food world further defines it as either metal nutrients with Recommended Daily Amounts (such as iron, manganese, and magnesium), or as heavy metals that pose health problems.
It is this second category that is usually meant when spoken by food producers/sellers/users. Among the most hazardous heavy metals are lead, mercury, arsenic, and cadmium.
Lead
Lead contamination can originate from several sources, including past use of lead in agricultural or industrial applications, such as pesticides, gasoline, and paint.
High levels can cause kidney and brain damage. It is especially damaging to children, which is why it has been banned from many consumer products, particularly children’s toys.
Mercury
Mercury contamination can cause chest pains, headaches, exhaustion, weight loss, and other problems. It is especially toxic when inhaled as a gas after it has been heated.
While not a natural element in food, it can contaminate the food supply if plants or animals ingest mercury from contaminated soil, water, or air.
Arsenic
Arsenic is considered a heavy metal, although it has non-metallic properties. Plants, particularly rice, can absorb it from the ground and cause arsenic poisoning. It is a naturally occurring element, but consuming excessive amounts, normally via contaminated drinking water, poses serious health risks, such as increased risk of cancer.
While inorganic arsenic has been shown to be more dangerous than organic arsenic, detrimental health effects due to excessive exposure to organic arsenic is being studied and is an area of concern. Typical testing methods measure the sum of both organic and inorganic arsenic present in the food, which is a faster, more reliable test.
Cadmium
Cadmium is present in the earth’s crust, but it is also a by-product of zinc refining practices. Plants can absorb cadmium, leading to health problems if consumed in excess, such as anemia, kidney failure, and increased cancer risk.
How to Test for Heavy Metals in Food
Testing for heavy metals in food is a relatively common analytical chemistry test that most food safety laboratories, like FSNS, can perform. The same steps apply for most products:
1. Sample Collection
- Collect random samples directly from the production line or off the shelf.
2. Sample Preparation at the Lab
- Homogenization to create a uniform sample for accurate testing.
3. Sample Digestion
- A small quantity is mixed with specific acids in a high-powered microwave, breaking down the product into a clear liquid.
4. Heavy Metal Analysis in Food
- Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is used.
- Analysis of common isotopes of lead, cadmium, mercury, arsenic, etc.
5. Reporting Results
- The lab creates a Certificate of Analysis (COA) detailing metal concentrations in parts per billion.
- The COA indicates concentrations, but doesn’t define pass/fail criteria – this depends on regulatory standards or company benchmarks.
Certified Laboratories, our fellow Certified Group company, provides a more detailed explanation of how to test for heavy metals in foods on its website. More specifically, they also explain how to test for heavy metals in spices here.
Food Safety Testing: Why are Heavy Metals Such a Hot Button Topic?
If heavy metal testing is a regular part of food safety testing done by both the FDA and many third-party testing facilities around the country, why is the topic of metals in food so prevalent?
One of the biggest stories in the last decade is that baby formulas have tested positive for arsenic, lead, cadmium, and mercury.
While some testing has shown the presence of these heavy metals in food, most consumers are unaware that many of these foods are infused with some metals deemed essential for the body, such as iron.
Many baby formulas and breakfast cereals are infused with iron to help supplement the minerals in a young child’s diet.
Heavy Metals in Dark Chocolate Raise Concern
Another story that turned heads was the discovery of potentially dangerous levels of lead and cadmium in some brands of dark chocolate.
A Consumer Reports study tested 28 brands of dark chocolate for lead and cadmium. Results showed that 23 brands contained levels of either lead or cadmium that exceeded California’s maximum allowable dose level of lead (0.5 micrograms) and cadmium (4.1 micrograms).
Five brands contained levels of both lead and cadmium that exceeded safe levels.
Because there are no Federal limits, scientists used California’s regulations since, Consumer Reports said, they are the “most protective available”.
In 2024, Consumer Reports again reported on lead contamination, this time in cinnamon powders, with the most egregious offender containing 3.52 ppm lead.
Where Do Heavy Metals in Food Come From?
Food manufacturers are not intentionally adding arsenic, lead, mercury, cadmium, and other heavy metals to the food and other products they sell to people.
Instead, these metals are often found in the soil, air, and water used to grow and cultivate the products that are later sold in stores. They also don’t degrade, so special care is needed to prevent them from being in the food in the first place.
For example, chocolate is made from the cacao bean. While dark chocolate contains antioxidants that provide health benefits, researchers have found that cacao plants absorb cadmium from the soil, which accumulates in the beans used to make chocolate. Since dark chocolate uses more cacao beans than other types of chocolate, it stands to reason that it has a higher likelihood of containing excessive cadmium.
Lead can contaminate the outer shell of the cacao bean after it is harvested and end up in the finished product we eat.
The same holds for rice, which absorbs more arsenic from the soil than other plants. That is one reason rice-based baby food can be susceptible to elevated arsenic levels.
Fish is also susceptible to heavy metals, particularly mercury. When fish ingest mercury from the water, it can accumulate in their bodies and present a challenge to food safety, underscoring the need for a robust food safety testing program.
Do Regulations Control Heavy Metals in Food?
The FDA has not established limits for heavy metals in food, but it does have limits for drinking water:
- Public drinking water: 15 ppb
- Bottled drinking water: 5 ppb
However, in its document Guidance for Industry: Juice HACCP Hazards and Controls, the FDA does say that lead levels above 50 ppb in juice may constitute a health hazard and “FDA may in the future establish an action level for lead in juice at levels above 50 ppb”.
In addition, CFR Title 21 establishes heavy metal limits for food contact materials, such as flatware and ceramic mugs.
California Prop 65 Limits Heavy Metals in Food
California has adopted regulations to help combat heavy metals contamination.
Anything made or grown in California is labeled with a warning regarding the presence of heavy metals found in the earth in which many products are grown.
Due to Proposition 65, all products that were grown in the ground or consumables and cosmetics made with such products must be labeled with the warning, even if no heavy metals (or other potentially harmful substances) are present in the product.
Food Safety Testing with Food Safety Net Services
Heavy metal analysis in food is a critical part of any food safety testing process because it checks for these potentially hazardous materials and helps identify where these materials are found in larger quantities. Once identified, necessary changes can be made to ensure consumer safety.
Here at Food Safety Net Services, a Certified Group company, we perform chemistry testing to identify and quantify lead, mercury, arsenic, cadmium, and other heavy metals to ensure a safe food supply.
Certified Laboratories, a Certified Group company, also performs heavy metals testing for food and other products. Reach out to us if you need heavy metals testing for your food products.
