Abstract
Background: Pekmez and pestil are traditional Turkish foods made from concentrated grape juice, which can be contaminated with mycotoxins such as aflatoxins and ochratoxin A (OTA). Objective: To carry out a single-laboratory validation of a method to simultaneously determine aflatoxins B1, B2, G1, and G2 and ochratoxin A in pekmez and pestil. Methods: The homogenized sample is extracted with methanol–water (80 + 20) using a high-speed blender. The (sample) extract is filtered, diluted with phosphate-buffered saline solution, and applied to a multi-immunoaffinity column (AFLAOCHRA PREP®). Aflatoxins and ochratoxin A are removed with (neat) methanol and then directly analyzed by reversed-phase LC with fluorescence detection using post-column bromination (Kobra cell®). Results: Test portions of blank pekmez and pestil were spiked with a mixture of aflatoxins and ochratoxin A to give levels ranging from 2.6 to 10.4 μg/kg and 1.0–4.0 μg/kg, respectively. Recoveries for total aflatoxins and ochratoxin A ranged from 84 to 106% and 80–97%, respectively, for spiked samples. Based on results for spiked pekmez and pestil (30 replicates each at three levels), the repeatability RSD ranged from 1.6 to 12% and 2.7–11% for total aflatoxins and ochratoxin A, respectively. Conclusions: The method performance in terms of recovery, repeatability, and detection limits has been demonstrated to be suitable for use as an Official Method. Highlights: First immunoaffinity column method validated for simultaneous analysis of aflatoxins and ochratoxin A in pekmez and pestil. Suitability for use for official purposes in Turkey, demonstrated by single-laboratory validation. Co-occurrence of aflatoxins and OTA in mulberry and carob pekmez reported for the first time.
A Low-Cost Palmtop High-Speed Capillary Electrophoresis Bioanalyzer with Laser Induced Fluorescence Detection
