Ochratoxin A producing fungi in stored peanut seeds from Córdoba province, Argentina

MAGNOLI, C.E; ASTORECA, A.L.; PONSONE, L; CHIACCHIERA S.; DALCERO, A

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE

Wiley InterScience

Año: 2006 vol. 86 p. 2369 - 2373

0022-5142

  Since there is no available information about the natural occurrence of ochratoxin producing fungi and ochratoxin A (OTA) in peanut seeds in Argentina, the aims of this work were to isolate and identify the Aspergillus section Nigri and to evaluate the natural occurrence of OTA in stored peanut seeds. Likewise, the capacity to produce OTA by Aspergillus section Nigri was studied. Forty seven samples of peanut seeds were obtained from a storage plant in the south of Córdoba Province, Argentina. Each sample of 100 seeds was surface- disinfected and plated onto a dichloran 18% glycerol agar (DG18). The OTA detection was performed by HPLC. OTA production in strains belonging to section Nigri was tested in YES medium (2% yeast extract, 15% sucrose). Aspergillus spp., the most frequent mold, occurred in 100% of samples, followed by Penicillium spp (87%) and Eurotium spp (6.4%). A. flavus was isolated in 100% of the samples, followed by A. niger var niger, A. niger var. awamori and A. carbonarius in smaller frequency, 89%, 68% and 4%, respectively. OTA was found in 32% of the peanut seed samples, with mean levels ranging from 0.5 to 170 ng g-1. The mean recovery of the method used was 85 ± 2%. Forty-three isolates (27%) of Aspergillus section Nigri, were found to be OTA producing strains. The highest percentage of ochratoxigenic strains (57%) was found within the A. carbonarius ssp. These results indicate a human exposure to OTA in Argentina through the ingestion of peanut seeds and peanut products.