Ochratoxin A production in relation to ecophysiological factors by Aspergillus section Nigri strains isolated from different substrates in Argentina

ASTORECA, ANDREA; MAGNOLI, CARINA; BARBERIS, CARLA; COMBINA, MARIANA; CHIACCHERA, STELLA; DALCERO, ANA MARÍA

SCIENCE OF THE TOTAL ENVIRONMENT

Elsevier

Año: 2007 vol. 388 p. 16 - 23

0048-9697

Contamination of foodstuff with mycotoxins such as ochratoxins is a major matter of concern for human and animal health. In Aspergillus species, ochratoxin synthesis depends on several environmental factors. The aims of this work were to evaluate the effect of water activity (0.995–0.85), temperature (15, 25 and 30 °C), incubation time (7, 14 and 21 days) and their interactions on OTA production on peanut, maize kernels, dried grapes and coffee beans meal extract agar medium by eight strains of Aspergillus section Nigri isolated from human food in Argentina. The optimum temperature for OTA production was 25 or 30 °C depending on the strains assayed, in most cases the highest OTA levels were achieved after 7 days of incubation, whereas this situation occurred 15 °C after 14 days of incubation for only one strain. The maximum OTA level was obtained at earlier growth states when incubation temperature increased. In general, OTA concentration increased as water activity (aW) increased with no significant production at 0.85–0.91 aW under all temperature levels tested. Production occurred over a range of temperatures (15–30 °C) with optimum production at 30 °C depending on aW assayed. The knowledge of Aspergillus section Nigri ecophysiology is critical in the development and prediction of the risk models of raw material and final product contamination by these species under fluctuating and interacting environmental parameters.Aspergillus species, ochratoxin synthesis depends on several environmental factors. The aims of this work were to evaluate the effect of water activity (0.995–0.85), temperature (15, 25 and 30 °C), incubation time (7, 14 and 21 days) and their interactions on OTA production on peanut, maize kernels, dried grapes and coffee beans meal extract agar medium by eight strains of Aspergillus section Nigri isolated from human food in Argentina. The optimum temperature for OTA production was 25 or 30 °C depending on the strains assayed, in most cases the highest OTA levels were achieved after 7 days of incubation, whereas this situation occurred 15 °C after 14 days of incubation for only one strain. The maximum OTA level was obtained at earlier growth states when incubation temperature increased. In general, OTA concentration increased as water activity (aW) increased with no significant production at 0.85–0.91 aW under all temperature levels tested. Production occurred over a range of temperatures (15–30 °C) with optimum production at 30 °C depending on aW assayed. The knowledge of Aspergillus section Nigri ecophysiology is critical in the development and prediction of the risk models of raw material and final product contamination by these species under fluctuating and interacting environmental parameters.