The Danish Consumer Council THINK Chemicals said the substances varied widely in quantity.
Forbrugerrådet Tænk said testing of 12 dark chocolate bars with a cacao content of 70% was in October last year.
Some bars were private label from Danish Supermarket chains Änglemark, COOP and Vores Chokolade. Others were Danish brands like Toms or non-Danish products such as Lindt, Lidl and Valrhona.
Analysis was by an unnamed chemical lab but testing for mineral oil was by the DIN EN 16995:2017 (modified) method including LC-GC/FID, for PAH by GC-MS and cadmium and lead by DIN EN 15763:2010 involving microwave digestion and ICP-MS.
Lindt Excellence 70% Dark and Tom's Extra Dark Chocolate 70% had the lowest content of ‘unwanted’ substances.
All chocolates tested contained cadmium. The heavy metal is transferred from soil to the cocoa beans and can end up in the finished bar of chocolate.
Only one, Valrhona's Noir Andoa 70% chocolate, had a content of cadmium above the impending EU limit for dark chocolate.
An entire bar covers the maximum intake of cadmium for about four days. 18g contains the daily amount of cadmium that authorities consider safe. Exceeding this limit does not pose an acute risk but could be a long-term risk, said Forbrugerrådet Tænk Kemi.
Mondelez (Marabou) to Forbrugerrådet Tænk
"We comply with all relevant rules and comply with the highest standards at global, EU and national level. The test results show that the content of the substances are within typical values for chocolate, including chocolate with high cocoa content."
Stine Müller, project manager of Forbrugerrådet Tænk Kemi, said the problem is the public is already exposed to relatively high amounts of cadmium from other food sources.
“The substance is present in cereals and vegetables, and in particular in grains and seeds like flax- and sunflower seeds. Therefore, it is important to consider your intake of dark chocolate as the content of cadmium in dark chocolate is so high and combined with other sources of cadmium you can easily get too much.
“Valrhona was the only bar with concentrations above the upcoming cadmium limit, but several of the other chocolates contained relatively high concentrations (around 200 - 250 micrograms of cadmium per kilogram of chocolate).
“It is below the limit, but it is still so high that If you eat around 100g a day of these chocolates, you will be exposed to all the cadmium that you can tolerate - without considering all the other sources.”
"We take the Danish Consumer Councils tests of our product very seriously. We will investigate what has caused the tested level of mineral oils, as our internal, regular studies show a lower level of mineral oils.”
Valrhona told Forbrugerrådet Tænk that cadmium can be found in the soil where cocoa beans are grown, especially in Peru, where the chocolate comes from.
“Valrhona is very aware of the production of chocolate that meets the applicable limit values. Right now, there are no limit values, but they will be introduced in 2019. We are working intensively with the Peruvian cooperative that produces the cacao beans, to ensure that Andoa Noir 70% will meet the applicable limit values in 2019."
Müller told us it also found amounts of lead in all the chocolates.
“The content of lead in Coop Dark 72% dark chocolate was highest in the test. It was 0.05 micrograms per kilogram of chocolate. Lead exists as contamination in many foods, and there are limit values for lead in many foods, but not for chocolate.”
PAH and mineral oil findings
PAHs and mineral oils were found in all tested chocolates but concentration was below EU limits.
All products contained PAH but two (Marabou and Vores chokolade) had a content ‘significantly higher’ than the 11 others.
Aldi (Moser Roth)
"We are sorry that traces of mineral oils have been found in our chocolate, especially because we have been working to phase-out mineral oils in cooperation with our supplier, Storck. In June, our supplier switched production to the new packaging, which is free of mineral oils."
All chocolates had an amount of mineral oil saturated hydrocarbons (MOSH) but in most cases these were smaller quantities.
The majority were without mineral oil aromatic hydrocarbons (MOAH) but two chocolate bars contained the compounds. These were Moser Roth Dark 70% Cocoa from Aldi and Fairglobe Dark Chocolate cocoa 70% from Lidl.
Müller said it does such work on a regular basis including chemical testing of food and food packaging material.
“Some years ago we did testing of chocolate advent calendars which showed content of mineral oils in the chocolate and was a very popular test, so we wanted to make some kind of a follow up. By choosing dark chocolate it was relevant also to include cadmium in the test,” she said.
“We always buy and test products as if we were actual consumers. We buy on the shelf and expect all products to be OK. This is how we test, not only chocolate but also all other products. We always send all the results from our chemical food testing to the Danish food authorities.
“We did not get any specific reaction from them, but Fødevarestyrelsen already has a recommendation on their website for consumers to consider the amount of dark chocolate that they eat due to the relatively high content of cadmium.”