Heavy metals in food

ifp Institut für Produktqualität provides heavy metal analysis as a service. Detection is done by means of atom absorption spectrometry (AAS) or stripping voltammetry after decomposing/mineralising the samples with acid in a microwave.

What is a heavy metal?

Heavy metals are not clearly defined in the literature. The public frequently defines all substances referred to as "heavy metals" as toxic. However, using the term in this sense is problematic since many of the elements are essential to humans, e. g. chrome, iron, cobalt, copper, manganese, molybdenum, nickel, vanadium, zinc and tin. Small amounts of these essential metals are referred to as trace elements.

Many heavy metals, such as lead, cadmium, mercury and copper, are indeed hazardous to health if ingested with food or even toxic since they cannot be broken down.

Food law requirements regarding heavy metals

The maximum levels for lead, cadmium, mercury and tin are specified in Regulation (EC)
No. 1881/2006 governing maximum contamination levels in certain foodstuffs. For foods not listed there, risk assessments are conducted in order to evaluate their contamination level. For this purpose the respective TDI (tolerable daily intake) and TWI (tolerable weekly intake) values – some of which are issued by the WHO or EFSA - are used.

Cadmium in cocoa and chocolate products

There are currently no food law requirements for heavy metals in cocoa and cocoa products. However, the German Federal Institute for Risk Assessment (BfR) recommended a maximum cadmium level of 0.1 – 0.3 mg/kg for chocolate in general as early as 2007. 

Since many fine cocoa types are from producing regions in Latin America, where the ground is rich in cadmium by nature, the cadmium concentration in chocolate produced from the fruit of such plants is naturally higher. So chocolate with a particularly high concentration of cocoa also has increased cadmium levels, which should be taken into account when specifying new limit values. Accordingly, the European Commission is currently considering the previously recommended limit value of 0.1 – 0.3 mg/kg for chocolate in relation to the cocoa content.

As of January 1st, 2019, maximum levels for certain cocoa and chocolate products will be regulated according to Regulation (EC) No. 1881/2006. For chocolates, the maximum levels for cadmium will be 0.1 - 0.8 mg/kg fresh weight, depending on the cocoa content. For cocoa powder, the maximum cadmium level will be 0.6 mg/kg fresh weight.