Building upon a December 2022 report on the levels of toxic heavy metals in dark chocolate, Consumer Reports recently published new findings about the contaminants in other kinds of chocolates, suggesting that one-third of chocolate products contain high levels of heavy metals.
Although dark chocolate contains the highest levels of cocoa, the ingredient in which lead and cadmium tend to accumulate, Consumer Reports sought to investigate the extent to which toxic heavy metals exist in milk chocolate and other cocoa-containing products.
The researchers tested 48 different products across seven categories, specifically: cocoa powder; chocolate chips; milk chocolate bars; and mixes for brownies, chocolate cake, and hot chocolate. Consumer Reports also tested some dark chocolate bars. Products were purchased from big name brands such as Hershey’s, Ghirardelli, and Nestlé, at national retailers like Costco, Target, Trader Joe’s, Walmart, and Whole Foods. Specialty makers, such as Droste and Navitas, were also included in the study.
To assess the risk from lead and cadmium, the researchers determined whether a serving of each product tested would cause exposure above California’s standard maximum allowable dose levels (MADL) for lead (0.5 micrograms [µg] per day) and cadmium (4.1 µg per day) in food.
As expected, dark chocolates tended to have higher levels of heavy metals compared to milk chocolate. However, every product that was tested had detectable amounts of lead and cadmium. Of the 48 products tested, 16 had amounts above Consumer Reports’ levels of concern for at least one of the heavy metals, in some cases exceeding more than twice the group’s limit.
Of the seven dark chocolate bars tested by Consumer reports, five (71 percent) were above the MADL for lead, cadmium, or both. Only two bars—Divine 70 Percent Deliciously Smooth Dark Chocolate and Sam’s Choice (Walmart) Dark Chocolate 85 percent Cocoa—fell below the MADL for both lead and cadmium, based on a serving of about 1 ounce (oz.).
Milk chocolate tends to be lower in heavy metals than dark chocolate because it has less cocoa solids, and none of the five tested milk chocolate bars were over the MADL for lead or cadmium. For chocolate chips, none of the 12 products tested had high levels of cadmium, and only two—Hu Dark Chocolate Gems and Good and Gather (Target) Semi-Sweet Mini Chocolate Chips—were over the MADL for lead. However, the serving size for chocolate chips is approximately 0.5 oz., and eating more than the recommended serving would likely expose a consumer to levels of cadmium and lead exceeding the MADLs.
Regarding cocoa powders, none of the samples exceeded the MADL for cadmium, and only two—Hershey’s Cocoa Naturally Unsweetened 100 percent Cacao and Droste Cacao Powder—exceeded lead limits (for a 1 tablespoon serving). However, for hot chocolate mixes, four of six samples exceeded the MADL for lead: Great Value (Walmart) Milk Chocolate Flavor Hot Cocoa Mix, Nestlé Rich Milk Chocolate Flavor Hot Cocoa Mix, Trader Joe's Organic Hot Cocoa Mix, and Starbucks Hot Cocoa Classic (also made by Nestlé).
None of the brownie and cake mixes tested were high in cadmium, and only one brownie mix and two cake mixes exceeded the MADL for lead: Ghirardelli Premium Brownie Mix Double Chocolate, Simple Mills Almond Flour Baking Mix—Chocolate Muffin and Cake, and Bob's Red Mill Gluten Free Chocolate Cake Mix. However, the recommended serving sizes are small compared to how some consumers portion their brownies and cakes, and could lead to elevated heavy metals exposure.
Although toxic heavy metals occur naturally in soil and are therefore difficult to remove completely from products, there are some steps that chocolate makers can take to make their products safer, such as sourcing from areas with lower levels and mixing beans from different areas to ensure that the final product has lower levels. Producers could also test lots of cocoa to identify problem areas and reject particularly contaminated lots.