The occurrence of ochratoxin A in blue cheese

Evidence for the occurrence of ochratoxin A in blue cheeses is reported for the first time. The development of an accurate and reliable procedure for the extraction of OTA from cheese, as well as the availability of a new sensitive HPLC-FLD method, has allowed us to determine ochratoxin A in complex matrices such as cheeses, even at very low levels (LOD in cheese: 0.02 μg/kg). A good linearity for the OTA concentration, between 0.2 and 2.5 μg/kg, was obtained and no matrix effect was observed in the same concentration range. The mean recovery for OTA was 97%, while the average RSD was 3%, within a spiking range of 0.5– 2.0 μg/kg. Although the OTA contamination levels found in blue cheeses were very low, occurrence of ochratoxin A in such products opens a new issue for risk assessment and quality control, as far as finding the origin of the OTA contamination and ways to prevent it.