Occurrence of benzene as a heat-induced contaminant of carrot juice for babies in a general survey of beverages

A survey of benzene contamination of 451 beverage samples, using headspace sampling combined with gas chromatography and mass spectrometry (HS-GC/MS) with a quantification limit of 0.13 microg l(-1), was conducted. Artefactual benzene formation during headspace sampling was excluded by gentle heating at 50 degrees C only and adjustment of sample pH to 10. The incidence of benzene contamination in soft drinks, beverages for babies, alcopops and beer-mixed drinks was relatively low, with average concentrations below the EU drinking-water limit of 1 microg l(-1). Significantly higher concentrations were only found in carrot juice, with the highest levels in carrot juice specifically intended for infants. About 94% of 33 carrot juice for infants had detectable benzene levels, with an average concentration of 1.86 +/- 1.05 microg l(-1). Benzene contamination of beverages was significantly correlated to iron and copper concentrations, which act as catalyst in benzene formation. The formation of benzene in carrot juice was predominantly caused by a heat-induced mechanism, which explains the higher levels in infant carrot juices that are subject to higher heat-treatment to exclude microbiological contamination.