Determination of Aflatoxins in Plant-based Milk and Dairy Products by Dispersive Liquid–Liquid Microextraction and High-performance Liquid Chromatography with Fluorescence Detection

Abstract

The consumption of plant-based milk has increased due to their nutritional attributes. However, these products may contain aflatoxins if contaminated raw materials were used, although little concern is present in international regulation regarding this topic. In this work, dispersive liquid–liquid microextraction (DLLME) was used for the determination of the most important aflatoxins (B₁, B₂, G₁, and G₂) in oat, rice, coconut, almond, and birdseed plant-based milk and milk-based products enriched with oats, almonds, and walnuts using high-performance liquid chromatography (HPLC) with photochemical derivatization and fluorescence detection. Calibrations in matrix were performed for all of the samples, obtaining satisfactory linearity, with correlation coefficients exceeding 0.994 for all of the aflatoxins. The precision in terms of repeatability and intermediate precision, expressed as the relative standard deviation, was lower than 9.7%, and recoveries ranged between 82 and 104%, fulfilling current legislation for the determination of aflatoxins. In addition, the limits of quantification were 0.5 µg L⁻¹ for the aflatoxins, allowing the determination of these compounds below the maximum levels established by European Commission in these commodities. Finally, 23 commercial products were analyzed to characterize the presence of these toxins.

Keywords:

• Aflatoxins
• dispersive liquid-liquid microextraction (DLLME)
• high-performance liquid chromatography (HPLC) with fluorescence detection
• plant product enriched milk
• vegetable-based milk

Disclosure statement

The authors report no conflicts of interest with this study.

Additional information

Funding

Financial support was provided from the Project Reference AGL2015-70708-R (MINECO/FEDER, UE). AMH thanks the Erasmus Mundus–Al Idrisi II program for a predoctoral grant.