Incidence of ochratoxin A in rice and dried fruits from Rabat and Salé area, Morocco

Abstract

One hundred samples of dried fruits (20 dried raisins, 20 walnuts, 20 peanuts, 20 dried figs and 20 pistachios) and 20 samples of rice purchased from retail shops in the Rabat and Salé area in Morocco were analysed for ochratoxin A (OTA) by immunoaffinity clean-up (IAC) and liquid chromatography (LC) with fluorescence detection. The limit of quantification (LOQ) (S/N = 10:1) of OTA was 0.02 ng g⁻¹ in rice, 0.03 ng g⁻¹ in pistachio, peanut and walnut, and 0.03 ng g⁻¹ in dried raisins and dried figs. The incidences of occurrence of OTA in dried raisins, walnuts, peanuts, dried figs and rice were 30, 35, 25, 65 and 90%, respectively. Analytical results showed that pistachio samples contained no detectable OTA, but concentrations ranged from 0.02 ± 0.01 to 32.4 ± 2.10 ng g⁻¹ in rice, from 0.10 ± 0.05 to 2.36 ± 0.75 in peanut, from 0.03 ± 0.01 to 1.42 ± 0.45 in dried figs, from 0.05 ± 0.02 to 4.95 ± 0.02 in dried raisins, and from 0.04 ± 0.01 to 0.23 ± 0.05 in walnuts. The results also showed that 15% of the total number of rice samples analysed exceeded the 2002 regulatory limit set by European Union regulations for cereals. This is the first report on the occurrence of OTA in dried fruits and rice available in Morocco.

Keywords:

• Ochratoxin A
• rice
• dried fruits
• Morocco

Acknowledgements

This research was supported by the Spanish Agency for International Cooperation ‘AECI’ (Programme Mixte Inter-Universitaire Maroco-Espagnol 2004, Project No. 128/P/M/04) and by the Spanish Ministry of Education and Science (No. AGL-2003-01407). A. Zinedine is most grateful to the Presidency of Mohamed V University Rabat-Agdal for their collaboration. C. Juan is thankful for a grant given by Spanish Ministry of Education and Science.