Optoelectronic System for Mycotoxin Detection in Food Quality Control

Here, we report on the design, fabrication, and characterization of a prototype of a portable detection system, able to determine if the contamination level of Ochratoxin A (OTA) is below or above the limit imposed by the EU Commission for a specific food. The operating principle of the system is the real-time monitoring of a chromatographic run when an extract of the sample under analysis is spotted on a high-performance thin-layer chromatographic plate. The idea is to induce naturally the fluorescence of the OTA molecules by using an ultraviolet excitation source and to detect the re-emitted light with an array of amorphous silicon photosensors, whose photocurrents will be proportional to the amount of OTA molecules. The system performances have been verified on sample containing pure OTA molecule and OTA extracted from fortified real matrices of wine and beer. The results showed a minimum detectable quantity of OTA of 0.2 ng and repeatability better than 5%. The analysis of the sample is made simultaneously with a reference, which, in the proposed system, corresponds to the amount of OTA equal to the limit for the specific food commodities. Taking into account the extraction efficiency and the minimum acceptable presence of OTA in such food commodities, we infer that the minimum amount of real matrix to be investigated is as low as 5.5 mL.