How Lead, Cadmium and Other Heavy Metals End Up in Chocolate

Which Heavy Metals Are Found in Chocolate?

Several heavy metals can make their way into chocolate during growing, processing, and manufacturing. Here are some of the most common:

Lead

Lead is linked to a variety of health problems and is especially toxic to children and pregnant women. Cocoa bean crops can uptake lead from contaminated soils, leading to finished chocolate products containing high lead levels.

Cadmium

Cadmium is linked to kidney, bone, and respiratory damage. Like lead, cadmium can transfer from contaminated soils and fertilizers into cocoa bean plants. It can also enter chocolate during manufacturing.

Arsenic

Arsenic exposure is associated with cancer risks along with cardiovascular, pulmonary, immunological, neurological and endocrine effects. Arsenic contamination in chocolate likely occurs during cultivation and processing.

Nickel

While nickel sensitivity is relatively rare, exposure can cause allergic reactions. Nickel may enter cacao crops from soil contamination and can transfer into chocolate products during manufacturing through stainless steel equipment.

How Do Heavy Metals Get Into Chocolate?

Heavy metal contamination can occur at several stages of chocolate production:

Growing Cocoa Beans

The source of cocoa beans plays a key role in heavy metal levels. Cacao plants readily absorb lead and cadmium from soil contaminated by pesticides, fertilizers, mining waste, factory emissions, or sewage runoff. Improper fermentation and drying processes also impact finished cocoa bean quality.

Processing Cocoa Beans

Contamination can occur during transport, storage, and processing steps through exposure to exhaust, dust, and metals from equipment. Fats, emulsifiers, sweeteners and other ingredients added during processing may also introduce heavy metals.

Manufacturing Chocolate

Finally, the chocolate production phase further impacts metal concentrations. Old or poorly maintained equipment may leach metals like nickel into products. Any additional ingredients offer another avenue for potential contamination as well.

Which Types of Chocolate Contain the Most Heavy Metals?

With so many chocolate options lining store shelves, should you play it safe and stick to certain varieties over others? Here is an overview of heavy metal risks based on chocolate type:

Dark vs Milk vs White Chocolate

Overall, dark chocolate has higher average levels of both lead and cadmium contamination compared to milk chocolate. This may stem from higher concentrations of cocoa solids. White chocolate contains no cocoa solids, but may still absorb metals through milk powders and other ingredients.

Unsweetened Chocolate

Unsweetened or baking chocolate is primarily just cocoa solids and cocoa butter. With little dilution from sugars and dairy, it tends to test higher in lead and cadmium than other chocolate types.

Cocoa Powders

Like baking chocolate, unsweetened cocoa powder contains very concentrated cocoa solids. Therefore, it also faces higher heavy metal risks. However, Dutch process alkalized cocoa powder may test lower thanks to pH changes during processing.

Chocolate Candy and Desserts

Finished chocolate products like candy bars, cookies and brownies contain chocolate along with other ingredients that dilute cocoa solid percentages. However, any ingredients from unreliable sources could also introduce contaminants.

How Much Cadmium and Lead Is Too Much?

While tiny amounts of heavy metals occur naturally in the environment, excessive accumulation in the body through contaminated foods and drinks poses health issues. Here’s a look at safe upper limits for the most concerning chocolate contaminants:

Cadmium

EU standards cap cadmium levels at 0.8 mg per kg of chocolate, while California sets stricter Proposition 65 requirements at 0.5 μg per day. Eating just one small 1.55-ounce chocolate bar could surpass daily limits for a 60-pound child under California standards.

Lead

California’s Prop 65 caps lead at 0.5 μg per day as well. Additionally, the FDA limit for lead in candy likely to be consumed by small children is 0.1 ppm.

Other Metals

Regulatory bodies have established guidance limits for heavy metals like arsenic, nickel and mercury too. While less data exists on typical exposure levels from chocolate, contamination risks still remain.

How to Choose Low Metal Chocolates

Choosing gourmet chocolate brands made from carefully sourced and processed cocoa beans can reduce exposure risks. Here are some buying tips for safer chocolates:

Check Company Testing Policies

Responsible chocolate makers test cocoa bean shipments and finished products for heavy metal contamination. Brands publishing strict testing guidelines typically offer greater transparency and accountability.

Select Organic Products

Opting for certified organic chocolate promotes sustainable, chemical-free cacao farming practices that lower heavy metal absorption risks during growing. However, contamination could still occur during processing.

Know the Country of Origin

Sourcing cocoa beans from countries with strict pesticide, soil quality and irrigation regulations minimizes metal exposure risks pre-harvest. However, environmental factors can vary between regions and farms.