In an article published on February 7, 2018, the Danish Consumer Council THINK Chemicals reported on a testing campaign measuring cadmium, lead, mineral oils, and polyaromatic hydrocarbons (PAHs) in twelve different brands of dark chocolate (70% cacao content). All of the tested chocolate bars contained all of the targeted substances with varying quantities, the Consumer Council informed. Five of the chocolates had elevated levels of one or more of the substances. In one chocolate bar, the amount of cadmium exceeded the upcoming EU limit value for cadmium in dark chocolate. Three chocolates contained mineral oil aromatic hydrocarbons (MOAH) in addition to mineral oil saturated hydrocarbons (MOSH). The remaining nine chocolates were free of MOAH, but contained MOSH. Two chocolate bars had increased levels of PAHs, however still below the EU limit values. The more detailed test results (in Danish, published on November 9, 2017) can be found here.
“Cadmium is transferred from the soil to the cocoa beans and therefore ends up in the finished bar of chocolate,” the Consumer Council explained. The heavy metal can accumulate in the liver and kidneys, and in the long term cause kidney damage. MOSH and MOAH contamination of food can occur during food production, processing, and packaging. One source is paper and board packaging, containing mineral-oil-based printing inks or recycled material. Also, the jute bags used to transport cocoa beans may be a contamination source. Mineral oils may also occur in additives and auxiliaries used in food processing or in lubricants used in food production, the Consumer Council noted. MOSH can accumulate in the body’s organs and MOAH is suspected to be carcinogenic. PAHs could be formed during roasting and drying. They have mutagenic and carcinogenic potential.
Danish Consumer Council THINK Chemicals (February 7, 2018). “Dark chocolate: These unwanted chemicals were found in test.”
Danish Consumer Council THINK Chemicals (November 9, 2017). “Test: Kemi i mørk chokolade.” (in Danish)