Liquid Chromatographic Determination of Ochratoxin A in Pure and Adulterated Soluble Coffee Using an Immunoaffinity Column Cleanup Procedure

Abstract

An immunoaffinity column/HPLC procedure was developed to quantify low levels of ochratoxin A (OTA) in green coffee beans, roasted coffee beans, and soluble (instant) coffee with greater than 80% recoveries. The method was used to survey 116 soluble coffee samples from various countries and different manufacturers and showed contamination levels ranging from “not detectable” to 15.9 μg/kg. The highest levels of OTA were detected among soluble coffees that had been adulterated with coffee husks and/or coffee parchments (mean contamination level: 5.9 μg/kg). By comparison, OTA concentrations in pure soluble coffee samples were significantly lower, with a mean contamination level of 1.1 μg/kg. Although higher than normal figures have been found in some products purchased in East European countries, the results of this survey indicate that pure soluble coffee is not a major source of OTA in the diet, with estimated intakes being well within safety limits. Keywords: Ochratoxin A; soluble coffee; analysis; HPLC; adulteration