Influence of roasting and brew preparation on the ochratoxin A content in coffee infusion.

A study of the effect of coffee processing in the ochratoxin A (OTA) level has been carried out from the green beans to the drinking form. The analysis of OTA has been carried out by an in-house validated HPLC method with fluorescence detection. The limits of detection were 0.04 microg/kg for green and roasted coffee, and 0.01 microg/L for coffee brew. Thirty-six green coffee samples of different origin (Colombia, Costa Rica, Brazil, Vietnam, India and Uganda) were analysed. The highest concentrations of OTA were found in Vietnamese samples -- Robusta species treated by dry processing -- (range 0.64-8.05 microg/kg), that also showed the highest percentage of defective beans (7.6%). These contaminated samples were roasted in a process that controlled loss of weight and color, as in the industry. A mean reduction of 66.5% was obtained, but the reduction seems to be heterogeneous. Coffee brew was prepared by the three brewing processes more utilized in Europe: moka, auto-drip and espresso. A reduction of the OTA level has been attained, being greater when using a espresso coffee maker (49.8%) than when using auto-drip (14.5%) or moka brewing (32.1%). Therefore, the method of coffee brew preparation plays a key role in the final OTA human exposure.

Determination of ochratoxin A in wine using liquid-phase microextraction combined with liquid chromatography with fluorescence detection.

A liquid-liquid microextraction technique (LPME) has been applied to the extraction of ochratoxin A (OTA) from wine prior to its quantification by HPLC-fluorescence detection. OTA was extracted from wine, through 1-octanol immobilized in the pores of a porous hollow fiber, and introduced into 1-octanol inside the fiber. Recovery was 77%. The method was adequate for quantification of OTA in wine at levels within the range 0.25-10 ng/ml with a LOD of 0.2 ng/ml, and can be a simple and inexpensive alternative to the use of inmunoaffinity columns in order to quantify OTA levels in wine.

Ocratoxina a en plasma humano: nuevos datos de exposición en España / Ochratoxin A in human plasma: new data of exposition in Spain

Se ha investigado la presencia de Ocratoxina A en plasma humano en la provincia de Granada, por medio del análisis de 83 muestras obtenidas de mujeres residentes en esa zona. El método analítico está basado en la extracción líquido-líquido, con posterior análisis por cromatografía líquida de alta resolución (HPLC) con detección de fluorescencia. Este método analítico ha sifo validaddo obteniéndose un límite de detección de 0,21 ng/mL. Se ha detectado la presencia de ocratoxina A en un 72 por ciento de las muestras. La concentración media hallada ha sido de 0,63 ng/mL, con una deviación estándar de 0,41 ng/mL y un rango de concentraciones entre 0,11 ng/mL y 6,96 ng/mL. Estos resultados son equiparables a los encontrados previamente en otras dos zonas del norte y del centro de España, y en los países del entorno. El análisis estadístico de los datos, por medio de un test de Kruskal-Wallis (n= 70; X2=4,591; p= 0,597), no evidenció que existiera ninguna diferencia significativa de los niveles plasmáticos de ocratoxina A en relación con la época del año en que fueron extraídas las muestras. Estos resultados constituyen una prueba más de la exposición generalizada de la población española a esta micotoxina, si bien el valor de la ingesta diaria de ocratoxina A calculado a partir de la concentración media hallada en el presente estudio, es muy inferior al máximo recomendado por el Comité de expertos sobre aditivos alimentarios de la Organización Mundial de la Salud (AU)