Recent Advances in the Detection of Aflatoxin M1 in Milk and Dairy Products

There is an increasing demand to design user-friendly specific assays for the detection of analytes of interest for healthcare, environment, and agrifood. Modern biotechnology has approached this problem by using proteins, enzymes, or RNA/DNA fragments (aptamers) as biological recognition elements for biosensors/assays. The idea is to exploit the extremely wide range of selective affinities sculpted into the various proteins or aptamers by biological evolution. The number of compounds specifically recognized by different proteins and aptamers is very large and ranges from small molecules to macromolecules. The advantages of using proteins and aptamers as molecular recognition elements (MRE) for assays/biosensors are many, and involve relatively low costs in design and synthesis, water solubility, and finally high specificity. Many of the analytes of interest in the food control industry are relatively small. In this case, aptamers and antibodies are widely used as specific MREs in designing advanced biosensors. Aflatoxin B1 (AFB1) is the most frequently found aflatoxin in contaminated food samples, and is one of the most potent natural compounds in terms of genotoxicity and carcinogenicity. Aflatoxin M1 (AFM1) is the hydroxylated metabolite of AFB1 and is usually found in milk and milk products as a carry-over of AFB1 in animals that have ingested contaminated feed. AFM1 is also found in human milk, and has been shown to be hepatotoxic and carcinogenic. Here, we present recent advances in assays and biosensors based on the use of antibodies and aptamers as MREs that have been developed for monitoring the presence of AFM1 in milk and dairy products. The limitations and advantages of aptamer- and antibody-based assays/biosensors are discussed, as well as future research perspectives.