Degradation products of aflatoxin M₁ (AFM₁) formed by high voltage atmospheric cold plasma (HVACP) treatment

Cold plasma technology is a novel non-thermal technology that has shown promising results for food decontamination and improving food safety. This study is a continuation of a previous investigation of the treatment of AFM₁-contaminated skim and whole milk samples by HVACP. Previous research has shown HVACP is effective in degrading aflatoxin M₁ (AFM₁) in milk. The goal of this study is to identify the degradation products of AFM₁ after HVACP treatment in pure water. An HVACP direct treatment at 90 kV using modified air (MA65: 65% O₂, 30% CO₂, 5% N₂) was performed for up to 5 min at room temperature on a 5.0 mL water sample in a Petri dish artificially contaminated with 2 μg/mL of AFM₁. The degradants of AFM₁ were analyzed and their molecular formulae were elucidated by using high-performance liquid-chromatography time-of-flight mass spectrometry (HPLC-TOF-MS). Three main degradation products were observed and based on mass spectrometric fragmentation pathways, chemical structures for the degradation products were tentatively assigned. According to the structure-bioactivity relationship of AFM₁, the bioactivity of the AFM₁ samples treated with HVACP was reduced due to the disappearance of the C8-C9 double bond in the furofuran ring in all of the degradation products.