Ochratoxin A in sultanas from Turkey I: Survey of unprocessed sultanas from vineyards and packing-houses

Abstract

A method for the determination of ochratoxin A (OTA) in sultanas from Turkey using extraction with a sodium bicarbonate solution (2% NaHCO3) followed by immunoaffinity clean-up and liquid chromatography with fluorescence detection was used to assess the frequency of occurrence and level of OTA. In-house validation was carried out with spiked samples at levels of 0.15, 1.5, 5.0 and 10 microg kg-1 and average recoveries were 91, 93, 87 and 89%, respectively. The limits of detection and limit of quantification in Turkish sultanas were 0.026 and 0.09 microg kg-1, respectively. A survey for the presence of OTA was carried out on 264 unprocessed sultana samples during the production seasons between 1998 and 2000 collected annually from vineyards and from packing-houses. The analyses of unprocessed sultanas showed that 32.2% of the total number of samples contained no detectable OTA, whereas 9.8% of sultana samples had OTA concentrations above 10 microg kg-1, and the remaining 58% had levels within the range 0.026-10 microg kg-1. There were big differences in median concentrations between years. Considering the year of production, it appears that sultanas produced in 1998 and 2000 showed the lowest incidence of OTA contamination (median<0.02 microg kg-1), whereas 2002 showed the highest incidence (median=4.3 microg kg-1). The overall mean OTA concentration was calculated as 3.4 microg kg-1, and the overall median as 0.9 microg kg-1. Among the samples analysed, the highest detected level of OTA was 54 microg kg-1.

Mycotoxins in botanicals and dried fruits: A review

“…Sample sizes that have been chosen for analysis are 500 g (Mö ller and Nyberg 2003; Lombaert et al 2004), 1000 g (MacDonald et al 1999) and 3000 g (Meyvaci et al 2005). The heterogeneity of OTA in dried vine fruits is well illustrated by the study of Mö ller and Nyberg (2003), who prepared slurries of 150-275 g subsamples of raisins or currants in aqueous sodium bicarbonate.…”

“…Some maximum levels of OTA reported in the literature are 35 mg g À1 in raisins analysed in Sweden (Mö ller and Nyberg 2003), 250 mg kg À1 in raisins in Egypt (Youssef et al 2000), 26 mg kg À1 in sultanas analysed in Canada (Lombaert et al 2004), 54 mg kg À1 in unprocessed sultanas in Turkey (Meyvaci et al 2005), 100 mg kg À1 in processed Turkish sultanas (Aksoy et al 2007), and 54 mg kg À1 in currants analysed in the UK (MacDonald et al 1999). Taking some of the data from four of these surveys as examples: Lombaert et al (2004) found 79% of 85 samples of raisins and 59% of 66 samples of sultanas contained OTA above 0.1 mg kg À1 with overall mean levels in all samples of 1.8 mg kg À1 for both raisins and sultanas; Meyvaci et al (2005) covered three production years for unprocessed sultanas in the Aegean region of Turkey, finding considerable variations in incidence and median levels with an overall mean level 3.4 mg kg À1 ; while Aksoy et al (2007) reported varying incidences over five years in processed Turkish sultanas (with a overall mean concentration ¼ 1.4 mg kg À1 ). MacDonald et al (1999) reported incidences of 95, 85, and 85% OTA40.2 mg kg À1 in 20 samples each of currants, raisins, and sultanas, respectively.…”

Survey of aflatoxins and ochratoxin a contamination in food products imported in Italy

“…Surveys for OTA in dried vine fruit (raisins, sultanas and currants) were carried out in many countries. About Turkey, Meyvaci et al (Meyvaci et al, 2005) covered three production years for unprocessed sultanas, finding a high incidence of OTA (68%) with an overall mean concentration of 3.4 mg kg À1 . Aksoy et al (Aksoy, Eltem, Meyvaci, Altindisli & Karabat, 2007) also reported OTA presence in 91% of processed Turkish sultanas taken during five crop years (overall mean concentration 1.4 mg kg À1 ).…”

A review on the occurrence and control of ochratoxigenic fungal species and ochratoxin A in dehydrated grapes, non-fortified dessert wines and dried vine fruit in the Mediterranean area

“…In addition, two Mediterranean countries, Greece and Turkey (Meyvaci et al, 2005), rank in first place in the world in terms of dried vine fruit production and exportation, making the Mediterranean area important also for this commodity.…”