Occurrence of ochratoxin A in roasted and instant coffees in Chilean market

The present report is a continuation of our previous studies about Ochratoxin A (OTA) presence in Chilean food chain. Following OTA determination in biological samples, cereals and wines, OTA contamination was for the first time determined in roasted and instant coffees commercialized in Chilean market. Sample preparation was carried out using immunoaffinity columns. Chromatographic conditions were optimized using a central composite design, establishing the following optimal conditions: mobile phase composed by water: acetonitrile: acetic acid (50:50:0.3, v/v/v), flow rate of 1.20 mL/min and column temperature of 45 degrees C. Validation was performed following the International Conference on Harmonization (ICH) recommendations. Data calibration curve (0.50-10.00 mu g L-1) fitted a linear regression model with a determination coefficient (R-2) of 0.998. Repeatability (relative standard deviation, RSD) and intermediate precision (RSD) in matrix showed values Of 0.57% (n = 6) and 0.36% (n = 3), respectively. Recovery (n = 3) at three levels ranged from 68.49% to 99.28%, (mean RDS 7.41%). Sixty-three samples, corresponding to twenty-four roasted coffees and thirty-nine instant coffees, were analyzed. OTA contamination showed a high incidence being detected in all coffee samples analyzed. The OTA levels observed in roasted coffee samples were lower than 1 mu g kg(-1) with a mean range from 0.30 to 0.84 mu g kg(-1). Instant coffee samples showed significantly higher OTA levels (P < 0.0001) than roasted coffee samples, with mean values ranging from 0.28 to 5.58 mu g kg(-1), exhibiting also the highest OTA content (7.25 mu g kg(-1)). OTA daily intake was estimated in 0.21 ng/kg b.w./day, which is much lower than the current tolerable daily intake. Therefore it seems that roasted and instant coffees marketed Chile have a minor contribution to OTA daily intake. (C) 2014 Elsevier Ltd. All rights reserved.