Manufactured cocoa products frequently have higher lead concentrations than other foods, even though cocoa beans, the main ingredient, have some of the lowest reported lead levels for any natural food. In 2001 the Codex Alimentarius Commission, an international body based in Rome, proposed reducing the maximum permissible level of lead in cocoa products by half, to 100 nanograms per gram (ng/g) for cocoa butter and 1,000 ng/g for cocoa powder. At a March 2002 meeting in West Africa, where most of the world’s cocoa supply originates, producers agreed that to reduce lead in their products, they needed research to identify the source of contamination. Now a U.S.–Nigerian research team has uncovered some of the first clues about where the lead is coming from [EHP 113:1344–1348].
Lead contamination of candies has been recognized as a problem since 1820, when a British study found the poison widespread in London confectionary products. In recent years, documented lead content in candy has ranged from a mean concentration of 21 ng/g in milk chocolate bars in an Australian study to an average of 1,920 ng/g in chocolates seen in research in India. In Nigeria, a 1999 study found an average of 310 ng/g lead in cocoa powders. (For comparison, the mean U.S. lead concentration for apples is 20 ng/g, 200 ng/g for dry table wine, and 100 ng/g for canned pineapple.) Lead is known to cause anemia, muscle weakness, and brain damage, with children particularly susceptible to effects.
In the current study, the researchers studied the lead isotopic compositions of cocoa beans and shells from six farms in Nigeria’s top three producing states to determine if soil or farm sources might be the cause of lead contamination. The team took bean and sediment samples and hom*ogenized them to make composites for soil, beans, and cocoa bean shells for each farm. They analyzed lead concentrations using high-resolution inductively coupled plasma mass spectrometry to make preliminary isotopic measurements, followed by thermal ionization mass spectrometry measurements.
The lead concentrations for cocoa beans ranged from less than 0.103 to 1.78 ng/g, averaging 0.512 ng/g—among the lowest lead concentrations reported for any food. The average concentrations found in the cocoa bean shells, however, was about 320-fold higher (160 ng/g). Soils showed a range of isotopic compositions overlapping those of the shells.
The cocoa bean shells all had an extremely similar isotopic composition, indicating a singular source of contamination, perhaps leaded gasoline. The authors conclude that although the soil may have caused a small degree of the contamination, the narrower range of isotopic composition in the shells suggested the more singular source of contamination was the true culprit. According to the paper, cocoa bean shells are known to be very effective at removing lead from solutions. So, although they provide excellent protection of the bean inside, the shells may also serve to contaminate the cocoa beans during fermentation or drying.
The team also compared the cocoa beans with finished cocoa products and found much higher lead concentrations and greater variability in the isotopic composition among the finished products. They therefore deduced that most of the contamination occurred after the cocoa left the farm stage.
The researchers conclude that while cocoa bean shells may be one source of lead, most contamination occurs during shipping or processing of the beans and in manufacturing. Further research on those stages of the process will help to isolate the source.
Searching for the golden ticket.
Cocoa beans are naturally low in lead, but cocoa products frequently are not. Now researchers are following new clues to identify the source of the contamination.
FAQs
Post-harvest lead contamination mostly happens during the outdoor fermentation and drying of beans, during which soil and dust that contain lead come in contact with the cacao bean shell, according to the committee. Fermentation of cacao beans occurs in bags, covered piles and wooden boxes.
Where does the lead in cocoa come from? ›
The researchers conclude that while cocoa bean shells may be one source of lead, most contamination occurs during shipping or processing of the beans and in manufacturing. Further research on those stages of the process will help to isolate the source.
How does chocolate get contaminated with heavy metals? ›
This happens because the cacao plants take up cadmium that's in the soil, which then accumulates in the beans as the trees grow, similar to how heavy metals contaminate some other crops. Lead, however, appears to get into cacao after beans are harvested.
What is the contamination of cocoa? ›
Some of the most common microbiological contaminants of cocoa are: Mold and yeast contamination: molds and yeasts can grow on cocoa when it is stored in high humidity and high temperatures. They can produce toxins that can affect food safety.
Does organic cocoa have lead? ›
Generally, cacao powder carries the highest concentration of heavy metals. It's made by essentially concentrating the solids of the cacao bean and removing the oils (known as cacao butter). Our current average cadmium content in our Cacao Powder is 0.4mcg/g. For lead, it's 0.01mcg/g.
Is Hershey's cocoa powder high in lead? ›
The Hershey's Naturally Unsweetened 100% Cacao contained 125% lead and 18% cadmium, while Droste Cacao Powder contained 324% lead and 41% cadmium. In comparison, Navitas Organics tested 77% lead and 17% cadmium.
Should I be worried about lead in dark chocolate? ›
Treat chocolate as a treat.
A single ounce of even one of the chocolates with the highest cadmium and lead levels in CR's tests is unlikely to cause any immediate harm. The risk comes with frequent consumption over time.
Does Trader Joe's chocolate still have lead in it? ›
In late 2022, a study in Consumer Reports claimed that dark chocolate from Trader Joe's and many other brands, including Dove, Lindt, and Hershey's, contained unsafe levels of lead, as well as cadmium.
What chocolate has the least amount of lead? ›
They used California's maximum allowable dose levels for lead (0.5 mcg) and cadmium (4.1 mcg) to highlight the best and worst brands, which are as follows. The brands found to have the lowest levels of heavy metal contamination are: Mast Organic Dark Chocolate (80% cocoa) Taza Organic Chocolate (70% cocoa)
What is the safest chocolate to eat? ›
Consumer Reports said safer choices include Mast Organic dark chocolate, Taza chocolate, Ghiardelli and Valrhona. “There are vegan 'milk chocolates' which would dilute the amount of cacao, and therefore theoretically lead and cadmium you would be taking in,” said Hunnes.
Hershey's milk chocolate also had the highest levels of lead in CR's tests. Some of Hershey's dark chocolate bars had some of the highest levels of lead and cadmium in CR's previous tests.
Does milk chocolate have lead? ›
And while they've detected cadmium and lead in some, the levels are typically very low, lower than the levels often found in dark chocolate. Still, while milk chocolate has lower levels of heavy metals, it typically has more sugar than dark chocolate.
What brands of chocolate are contaminated? ›
One-Third of Chocolate Products Are High in Heavy Metals—Here's What to Know. Brands like Trader Joe's, Walmart, Ghirardelli and Hershey's are among the affected products.
Which cocoa powder does not have lead? ›
Scientists with the consumer watchdog group tested six different cocoa powder brands in the latest survey, and Navitas Organics had the lowest levels of both lead and cadmium within the entire category.
How to detox lead from body? ›
Heavy metal detox foods to eat include:
- cilantro.
- garlic.
- wild blueberries.
- lemon water.
- spirulina.
- chlorella.
- barley grass juice powder.
- Atlantic dulse.
The maximum allowable dose for lead in a food product is 0.5 micrograms, and for cadmium it's 4.1 micrograms. In one of Ghirardelli's chocolates, one ounce contained 36 percent of the maximum allowable amount of lead and 39 percent of the maximum allowable amount of cadmium.
Which chocolate has no lead or cadmium? ›
The brands found to have the lowest levels of heavy metal contamination are: Mast Organic Dark Chocolate (80% cocoa) Taza Organic Chocolate (70% cocoa) Ghirardelli Intense Dark Chocolate/Twilight Delight (86% and 72% cocoa, respectively)
What chocolate has the most lead in it? ›
Chocolates With the Most Heavy Metals
- Perugina 85% Premium Dark Chocolate: 1 oz contains 539% lead, 68% cadmium.
- Hershey's Milk Chocolate Bar: 1 oz contains 67% lead, 31% cadmium.
- Hu Dark Chocolate Gems: 1 tbsp contains 121% lead, 20% cadmium.
- Droste Cacao Powder: 1 tbsp contains 324% lead, 41% cadmium.
Vomiting, constipation, abdominal pains, headaches, mood disorders, high blood pressure, tingling sensations and fatigue can all be the result of lead poisoning, but of course these symptoms can also have other causes.
Why is there cadmium in cocoa? ›
Chocolate contains many nutrients good for your health but is sometimes contaminated by Cadmium, a toxic heavy metal, present in the soil of some cocoa plantations. been classified as a human carcinogen. Cadmium can be found naturally in soil because of volcanic activity, forest fires and weathering of rocks.
