Simultaneous Detection and Quantification of Aflatoxin M1, Eight Microcystin Congeners and Nodularin in Dairy Milk by LC-MS/MS

Dairy milk holds a prominent position as a widely consumed food, particularly among infants and children. However, it is crucial to address the presence of multiple natural toxic compounds that may co-occur in dairy milk to ensure its safety prior to consumption. Aflatoxin M1 (AFM1), an emerging mycotoxin of interest, is a potential contaminant in the milk of animals who ingest aflatoxin B1 (AFB1). The toxin is regulated in the European Union under Commission Regulation No 1881/2006. Unfortunately, there is a notable lack of data concerning the transfer of various emerging microbial contaminants into dairy milk and, therefore, their natural occurrences. In this study, a simple and sensitive LC-MS/MS method was developed and validated for the quantification of multiple cyanotoxins (microcystin congeners and nodularin) and AFM1 by the main analytical guidelines. Toxins are extracted with methanol 80%, followed by an SPE clean-up step before LC-MS/MS analysis. The LOQ was fixed at 1 µg/L for the nine cyanotoxins and 0.05 µg/L for AFM1. Recoveries were measured between 82.67% and 102%. To the best of our knowledge, there are no other LC-MS/MS methods available for the simultaneous quantification of cyanotoxins and mycotoxins in milk.