Ochratoxin A determination in ham by immunoaffinity clean-up and a quick fluorometric method

Abstract

A simple and rapid method for the determination of ochratoxin A (OA) in ham was developed using a basic methanolic extraction, immunoaffinity column clean-up and a fluorometric determination of the toxin contamination levels. A mean recovery of OA from ham samples spiked at levels from 0.7 to 9.7 µg kg-1 was 83 ± 6% using the fluorometric method, with a detection limit of 0.7 µg kg-1. Recovery data were compared statistically with those obtained using reversed-phase high-performance liquid chromatography with acetonitrile-water-acetic acid (99:99:2) as mobile phase and fluorescence detection, commonly used for OA determination in food. A good correlation between the two analytical techniques was obtained. Both methods were successfully applied to 42 ham samples, 21 in the middle of the ripening period (after 6 months from the process beginning) and the other 21 at the end of the maturation, after 12 months. Twenty-seven samples (64%) showed an OA contamination level <1.0 µg kg-1, the Italian Ministry of Health guideline. The maximum contamination level found was 2.3 µg kg-1. A good agreement (R2 = 0.980) between HPLC and fluorometer analysis on naturally contaminated samples was obtained.