Validation of a liquid chromatography method for the simultaneous quantification of ochratoxin A and its analogues in red wines

A validated high-performance liquid chromatography (HPLC) method with fluorescence detection for the simultaneous quantification of ochratoxin A (OTA) and its analogues (ochratoxin B (OTB), ochratoxin C (OTC) and methyl ochratoxin A (MeOTA)) in red wine at trace levels is described. Before their analysis by HPLC-FLD, ochratoxins were extracted and purified with immunoaffinity columns from 50 mL of red wine at pH = 7.2. Validation of the analytical method was based on the following parameters: selectivity, linearity, robustness, limits of detection and quantification, precision (within-day and between-day variability), recovery and stability. The limits of detection (LOD) in red wine were established at 0.16, 0.32, 0.27 and 0.17 ng L-1 for OTA, OTB, MeOTA and OTC, respectively. The limit of quantification (LOQ) was established as 0.50 ng L-1 for all of the ochratoxins. The LOD and LOQ obtained are the lowest found for OTA in the reference literature up to now. Recovery values were 93.5, 81.7, 76.0 and 73.4% for OTA, OTB, MeOTA and OTC, respectively. For the first time, this validated method permits the investigation of the co-occurrence of ochratoxins A, B, C and methyl ochratoxin A in 20 red wine samples from Spain

Quantification of ochratoxin A and five analogs in Navarra red wines

Ochratoxin A (OTA), B (OTB) and their methyl (MeOTA, MeOTB) and ethyl (OTC, EtOTB) esters were evaluated in 51 red wine samples from Navarra (Spain). Detectable levels of OTA and OTB were found in 100% of the samples, and 71% showed the presence of OTC. The six ochratoxins appeared simultaneously in 18% of the samples. Results indicated that OTC is hydrolyzed to OTA in red wine. Therefore, ochratoxin intake from wine can be underestimated when only assessed by OTA analysis. Analyzed Navarra wines are scarcely contaminated with ochratoxins and their contribution to human intake is low, with the worst case being 4.7% and 6.6% of the provisional tolerable weekly intake (PTWI) for OTA and for the sum of ochratoxins, respectively. No significant differences were generally found between vintages. With the exception of OTA, no significant differences were observed between organic and traditional farming. Levels of ochratoxins were positively correlated with temperature and inversely correlated with humidity and rainfall

Levels of ochratoxins in Mediterranean red wines

The co-occurrence of ochratoxin A (OTA) and its five analogs (OTB, OTC, MeOTA, MeOTB and EtOTB) in 96 red wine samples from Mediterranean countries has been demonstrated, for the first time, in this study. OTA was detected in 99 % of the samples (<LOD-455 ng·L-1). This mycotoxin appeared simultaneously with OTB (2.05 - 119 ng·L-1) in all the samples and in 89.6% of them OTC (<LOD - 31.5 ng·L-1) also accompanied both. OTB appears at comparable levels and incidence just like OTA does, and OTC median concentration is approximately 10 % of that of OTA. A high statistical association was found between the concentrations of OTA-OTB and OTA-OTC. MeOTA, MeOTB and EtOTB were detected in 62.5, 83.3 and 83.3 % of the samples, respectively. In 44.8 % of the wines, the 6 ochratoxins appeared simultaneously. There was no evidence for ochratoxin A levels being greater in wines from Southern Europe than those described from North Europe. Samples from North Africa presented statistically the highest values for OTA, OTB, OTC and EtOTB

Incidencia y niveles de Ocratoxina A y cinco análogos en vino tinto

The natural presence of OTA in wine has been reported worldwide. However, this is the first investigation that has demonstrated the co-occurrence of several ochratoxins in 51 red wines from Navarra (Spain) and 96 samples from 8 Mediterranean countries. This fact is partly due to the low limits of detection and quantification obtained. An HPLC-FLD analytical method was developed and validated for the simultaneous quantification of ochratoxin A (OTA), ochratoxin B (OTB) and their methyl and ethyl esters (methylochratoxin A (MeOTA), ochratoxin C (OTC), methylochratoxin B (MeOTB) and ethylochratoxin B (EtOTB)) in red wine. No samples exceeded the 2 µg/L maximum permitted by the EU for OTA in wine. Simultaneous occurrence of OTA and OTB were found in 100% of the samples. In addition, 90% of the Mediterranean wines presented OTC and the six ochratoxins were detected in 45%. OTA-OTB and OTA-OTC concentrations showed a very large positive association between each other. In general, levels were not influenced by the country of origin except in the case of Tunisia and Algeria, whose concentrations were statistically higher. Some factors that could affect the ochratoxin levels were investigated. In general, no significant differences were found between vintages. With the exception of OTA, no significant differences were observed between organic and traditional farming. Concentrations were positively correlated with temperature and inversely correlated with humidity and rainfall during the summer prior to grape harvesting. OTC transformation into OTA in red wine was also examined. The results obtained suggested that OTC hydrolyzed to OTA in wine

Incidencia y niveles de Ocratoxina A y cinco análogos en vino tinto

The natural presence of OTA in wine has been reported worldwide. However, this is the first investigation that has demonstrated the co-occurrence of several ochratoxins in 51 red wines from Navarra (Spain) and 96 samples from 8 Mediterranean countries. This fact is partly due to the low limits of detection and quantification obtained. An HPLC-FLD analytical method was developed and validated for the simultaneous quantification of ochratoxin A (OTA), ochratoxin B (OTB) and their methyl and ethyl esters (methylochratoxin A (MeOTA), ochratoxin C (OTC), methylochratoxin B (MeOTB) and ethylochratoxin B (EtOTB)) in red wine. No samples exceeded the 2 µg/L maximum permitted by the EU for OTA in wine. Simultaneous occurrence of OTA and OTB were found in 100% of the samples. In addition, 90% of the Mediterranean wines presented OTC and the six ochratoxins were detected in 45%. OTA-OTB and OTA-OTC concentrations showed a very large positive association between each other. In general, levels were not influenced by the country of origin except in the case of Tunisia and Algeria, whose concentrations were statistically higher. Some factors that could affect the ochratoxin levels were investigated. In general, no significant differences were found between vintages. With the exception of OTA, no significant differences were observed between organic and traditional farming. Concentrations were positively correlated with temperature and inversely correlated with humidity and rainfall during the summer prior to grape harvesting. OTC transformation into OTA in red wine was also examined. The results obtained suggested that OTC hydrolyzed to OTA in wine

Quantification of ochratoxin A and five analogs in Navarra red wines

Ochratoxin A (OTA), B (OTB) and their methyl (MeOTA, MeOTB) and ethyl (OTC, EtOTB) esters were evaluated in 51 red wine samples from Navarra (Spain). Detectable levels of OTA and OTB were found in 100% of the samples, and 71% showed the presence of OTC. The six ochratoxins appeared simultaneously in 18% of the samples. Results indicated that OTC is hydrolyzed to OTA in red wine. Therefore, ochratoxin intake from wine can be underestimated when only assessed by OTA analysis. Analyzed Navarra wines are scarcely contaminated with ochratoxins and their contribution to human intake is low, with the worst case being 4.7% and 6.6% of the provisional tolerable weekly intake (PTWI) for OTA and for the sum of ochratoxins, respectively. No significant differences were generally found between vintages. With the exception of OTA, no significant differences were observed between organic and traditional farming. Levels of ochratoxins were positively correlated with temperature and inversely correlated with humidity and rainfall

Levels of ochratoxins in Mediterranean red wines

The co-occurrence of ochratoxin A (OTA) and its five analogs (OTB, OTC, MeOTA, MeOTB and EtOTB) in 96 red wine samples from Mediterranean countries has been demonstrated, for the first time, in this study. OTA was detected in 99 % of the samples (<LOD-455 ng·L-1). This mycotoxin appeared simultaneously with OTB (2.05 - 119 ng·L-1) in all the samples and in 89.6% of them OTC (<LOD - 31.5 ng·L-1) also accompanied both. OTB appears at comparable levels and incidence just like OTA does, and OTC median concentration is approximately 10 % of that of OTA. A high statistical association was found between the concentrations of OTA-OTB and OTA-OTC. MeOTA, MeOTB and EtOTB were detected in 62.5, 83.3 and 83.3 % of the samples, respectively. In 44.8 % of the wines, the 6 ochratoxins appeared simultaneously. There was no evidence for ochratoxin A levels being greater in wines from Southern Europe than those described from North Europe. Samples from North Africa presented statistically the highest values for OTA, OTB, OTC and EtOTB