Determination of aflatoxin B₁ in tiger nut-based soft drinks

Abstract

An analytical method for the determination of aflatoxin B₁ in a tiger nut-based soft drinks named ‘horchata’ is described. The method is based on an immunoaffinity clean-up, followed by HPLC separation and fluorescence detection after electrochemical post-column derivatization. The detection limit (S/N = 3) and the quantification limit (S/N = 10) were 0.02 and 0.06 µg kg⁻¹, respectively. The mean recovery at a level of 2 µg l⁻¹ was 88% (n = 6) and the coefficient of variation was 9%. The method was applied to conduct a small market survey for a beverage named ‘horchata’ that is frequently consumed by parts of the population in Southern Europe. Twenty-two samples from Spanish and Belgian supermarkets were analysed. As a result, only one sample was found to contain aflatoxin B₁ at the limit of quantitation of the method.

Keywords:

• Aflatoxin B₁
• tiger nuts
• ‘chufa’
• ‘horchata’
• high-performance liquid-chromatography

Acknowledgements

The authors are grateful to the RIVM, Bilthoven, the Netherlands, for providing the aflatoxin standard and to the Regulating Council of Denomination of Origin ‘Chufa de Valencia’ (CRDO), Valencia, Spain, for providing technical information about horchata consumption in Spain.