How do heavy metals get in beer and wine?

Arsenic and Co can pass from filter material to the alcoholic beverages

Beer can contain toxic heavy metals like arsenic. © Givaga / thinkstock
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Weighted luxury: Beer and wine can be contaminated with toxic heavy metals such as arsenic - even in Germany. A possible source of this contamination has now been confirmed by researchers. According to this, the substances enter the drinks through a filter material that is frequently used during production - diatomaceous earth. The good news: There are ways to reduce this heavy metal transfer.

In many places, our environment is contaminated with harmful heavy metals. Mercury, arsenic, lead, cadmium and co can be found naturally in soil and groundwater, but also by ore mining, industrial and transport emissions and agricultural fertilizers and pesticides. As a result, foods such as rice, mushrooms and lettuce are now often contaminated with heavy metals.

Also in beer and wine already increased amounts of arsenic were detected. However, preliminary research indicated that the groundwater used to make the drinks was not responsible for this contamination. The source therefore had to be in the manufacturing process itself.

Contaminated kieselguhr

Benjamin Redan of the US Food and Drug Administration (FDA) in Bedford Park and his colleagues have now looked more closely at one potential source of exposure: diatomaceous earth - a substance from the shells of fossil diatoms used in beer and wine production Filter material is used. "This diatomaceous earth could contain elevated levels of heavy metals such as arsenic, lead and cadmium, " they write.

Whether this is really true, the researchers tested with three popular kieselguhr species. And indeed, all of these substances used in the food industry contained arsenic and small amounts of lead and cadmium. But can these metals reach the drinks during filtration? display

Increased arsenic levels

Redan and his team filtered ale, lager beer, red wine, and white wine with diatomaceous earth, and then added the heavy metal concentration in the beverage. It was found that in the process, a part of the metals in the final product berging. In one case, the arsenic concentration increased by 3.7 to 7.9 times compared to the unfiltered beverages.

This was above the US authorities recommended limit for apple juice, which is at ten ppb (parts per billion), as the scientists report. Official limit values ​​for heavy metals in beer and wine do not exist so far.

Washing helps

Samples of beer and wine from the retail sector revealed that such high values ​​seem to be the exception but occur. For example, two wines studied for the study contained arsenic concentrations of 11 and 18 ppb. How could the amount of such heavy metals be reduced in the future?

To find out, the researchers took different measures under the microscope. It turned out that the amount of the transitional metals depends, among other things, on the amount of filter material used. In addition, the previous washing of the kieselguhr also had an effect. Thus, washing with water as well as with citric acid or the complexing agent EDTA could significantly reduce the arsenic concentration. EDTA also had a positive effect on lead concentration, the team reports.

Transfer can be minimized

"These results indicate that steps to minimize the heavy metal transfer of kieselguhr filter materials to beer and wine, " write Redan and his colleagues. They now want to carry out further investigations in order to confirm their experimental observations on a larger scale. (Journal of Agricultural and Food Chemistry, 2019; doi: 10.1021 / acs.jafc.8b06062)

Source: American Chemical Society

- Daniel Albat