effect of temperature on production of ochratoxin a by aspergillus niger in orange juice

This challenging study was carried out to evaluate the temporal production of ochratoxin A (OTA) byAspergillus nigerATCC 16404 and wild typeA. nigerAM at different temperatures in fresh squeezed orange juice (Citrus sinensis[L.] Osbeck cv Tarocco). Each strain, inoculated into the filtered orange juice, was incubated at 4°C, 20°C, and 26°C for 28 days. In the juice, at 26°C and 20°C, the concentration ofA. nigerATCC 16404 increased by more than 2 log10up to the 21st day. At 4°C it remained constant. The microbial load ofA. nigerAM decreased at all temperatures. At 26°C, the maximum OTA accumulation found was 3.44 ng/mL on the 21st day forA. nigerATCC 16404 and 8. 44 ng/mL on the 7th day forA. nigerAM. The OTA synthesis seemed to be an intrinsic strain-dependent mechanism.A. nigerATCC 16404 produced OTA in accordance with the higher temperatures and the biomass concentrations, whereasA. nigerAM produced the toxin at all temperatures regardless of its biomass. These results showed that fresh orange juice contaminated withAspergillus nigeraggregate strains may contain OTA levels.