Degradation of Aflatoxin M1 in skim and whole milk using high voltage atmospheric cold plasma (HVACP) and quality assessment

Abstract

Cold plasma technology is a novel non-thermal technology that has shown promising results for food decontamination and improving food safety. This study investigates the efficacy of high voltage atmospheric cold plasma (HVACP) system to reduce Aflatoxin M₁ (AFM₁) in skim and whole milk. A dielectric barrier discharge HVACP was employed at 90 kV using modified air (MA65: 65 % O₂, 30 % CO₂, 5 % N₂) fill gas for 1,3, and 5 min. Skim and whole milk was spiked with 1.0 μg/L AFM₁ and exposed to HVACP treatment in both direct or indirect mode with no post-treatment storage or 4.0 h post storage at room temperature. Optimum condition of toxin degradation was chosen as for quality assessment including color, conductivity, total dissolved solid (TDS), pH, viscosity, peroxide value (PV), Thiobarbituric acid reactive substance (TBARS) assay, Fourier-transform infrared spectroscopy (FTIR), as well as nutrient composition. A one-minute HVACP treatment degrades 41.9 % and 37.8 % of AFM₁ in skim milk and whole milk, respectively. However, much greater reductions were seen after a short treatment and then post-treatment storage. A greater than 87 % reduction in AFM₁ was observed for all samples after a 3 min HVACP treatment with 4.0 h of post treatment. These results suggest that a few minutes of HVACP treatment is sufficient to generate significant reactive plasma species in the milk. Quality changes were less significant with shorter post treatment time and indirect mode of exposure. Overall, HVACP is an effective solution for decontamination of milk from AFM₁.

Keywords: Aflatoxin; Cold plasma; Food safety; Milk; Milk quality.