Determination of aflatoxin levels in nut samples sold in the diyarbakir market using the HPLC method

Aim: The aim of this study was to determine the aflatoxin contamination levels in walnut kernels and boiled watermelon seed samples offered for sale in the central districts of Diyarbakır province (Bağlar, Kayapınar, Sur, and Yenişehir), and to evaluate the findings in terms of public health. Material and Method: A total of 60 samples (30 walnut kernels, 30 watermelon seeds) were randomly collected from various sales points during February–March 2024. The samples were analyzed using High-Performance Liquid Chromatography (HPLC) according to AOAC Official Method 991.31. Instrument calibration was achieved with standard solutions prepared between 0.1–20 ng/mL; the limit of quantification (LOQ) for AFB₁ was determined as 1.0 µg/kg, and for total aflatoxins (AFB1+AFB2+AFG1+AFG2) as 2.52 µg/kg. Results: Based on the analyses, no AFB₁ or total aflatoxins (AFB1+AFB2+AFG1+AFG2) were detected in any of the 30 walnut kernel and 30 watermelon seed samples. It was determined that the districts where the samples were collected or the types of businesses where they were offered for sale (market or nut shop) had no significant effect on aflatoxin levels. Conclusion: The aflatoxin levels detected in the analyzed walnut and watermelon seed samples do not appear to pose a significant public health risk when evaluated within the framework of current analytical conditions and legal limits. However, it is known that even low-dose exposures may lead to long-term health effects, especially in children and vulnerable populations. Therefore, seasonal monitoring should be conducted throughout the year, particularly for unpackaged products sold in open markets. Risk-based inspections should be increased and consumers should be educated about aflatoxin contamination. While the study provides positive data for regional food safety, it also highlights the need for continuous monitoring.