A team of scientists have designed a simplified, sensitive test that can identify the mycotoxin ochratoxin A in food products, which can cause serious harm if ingested.
Ochratoxin A (OTA), a naturally occurring mycotoxin, is a secondary fungal metabolite produced by Aspergillus and Penicillium species. It is found in a wide range of commodities such as cereal-based foods (including animal feeds), dried fruit, coffee and wine. Ingestion has been linked to liver and kidney damage, immunotoxicity and is classified as a carcinogen in humans. The EU have set maximum levels for plant derived foods for human consumption, however, there is currently no limit for animal-derived foods.
In a recent study, the team of researchers from Shenyang Agricultural University and the Chinese Academy of Agricultural Sciences set out to investigate the extent of contamination in animal-derived products. However, as existing methods for OTA quantification relied on time-consuming, complicated procedures that increase the opportunity for error the group had to develop another method.
Using a Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) they were able to extract from complex matrices and detect trace levels of OTA.
The method was validated for grapes, grape products and food of animal origin, including eggs, milk chicken and pork. Excellent sensitivity was achieved in negative ionization mode. The extraction solvent and sorbent were found to be critical for the detection of OTA in different matrices. Acetonitrile was identified as the optimal extraction solvent for grape products, whilst acetonitrile containing 5% acetic acid (v/v) was optimal for foods of animal origin. In all cases octadecylsilane was a suitable sorbent.
In total, 717 field samples from the food chain, including producers, wholesalers, warehouses and stores, were tested. No OTA was identified in any of the animal products. However, high levels of OTA were present in raisins but not grapes or grape juice. These findings suggest grape processing procedures require review to address the problem.