The recent discovery of pesticide residues in drinking water from some smaller natural reservoirs in Denmark was unexpected and led to concern among consumers and health authorities. The use of synthetic chemicals to increase crop yields has attracted critical attention, and increasing number of consumers and producers of agricultural products are now actively avoiding the association of food products and pesticides. Carlsberg Research Laboratory has initiated a project aimed at monitoring pesticide residues in water and in brewing raw materials.
Analyses of pesticide residues are carried out by state-of-the-art instrumentation under rigorous quality control. Pesticides in drinking water are primarily herbicides. These chemical compounds are stable, polar and tend to follow the rainwater on its way to the water table. The analysis, as seen from the chemist's point of view, is challenging. In the EU, the permissible maximum residue level of any individual pesticide in drinking water is 0.1 ppb - or 0.1 µg/litre. This is a very small fraction; it corresponds to finding one particular grain of sand in two cubic meters of sand. In barley the maximum residue levels are higher: 50 µg/kg - 500 µg/kg for most pesticides, but their extraction from the sample is more complicated.
Using a new quality control tool, no pesticide residues, at a level of 0.05 ppb or above, have yet been found in brewing water samples from Denmark or abroad.
Trace levels of herbicides and fungicides in barley have been demonstrated, but the concentrations were a factor 50-100 below the EU maximum residue levels for barley.
These new quality assurance measures will, added to the traditional water and malt analyses, help to ensure that Carlsberg and Tuborg beers worldwide are brewed only from raw materials that comply with the strictest quality demands.