Comprehensive overview and critical perspective on the analytical techniques applied to aflatoxin determination – A review paper

Aflatoxins represent secondary metabolites of fungi, being characterized by a high degree of toxicity. They are classed as poisonous mycotoxins, hence the interest in the control of their level. 20 fungal metabolites compose the class of aflatoxins, that structurally derive from difuranocoumarin. Aspergillus flavus and Aspergillus parasiticus are the main species producing fungal metabolites in cereals, peanuts and animal feeds. Aflatoxins B1, B2, G1, G2, M1 and M2 are the most often encountered. Sample preparation techniques are crucial steps in aflatoxin analysis: they rely on liquid–liquid extraction or solid-phase extraction. Chromatographic methods ensure separation, advanced purification of analytes, which are subsequently quantified through detection techniques. The latter encompass optical methods, mass spectrometry and electroassay. Many analytical methods like ELISA, fluorescence polarization immunoassay, lateral flow immunoassay or PCR impart selectivity by using biorecognition elements: enzymes, antibodies or a DNA sequence. Given the high toxicity and presence of aflatoxins in food and agricultural products, their determination is an essential element in food safety. The analysis method is chosen according to the nature of the sample (type of matrix), the available equipment, the concentration range in which the toxin's level is placed, sensitivity and detection limit, precision, selectivity, required analysis time, personnel training. The present paper provides a comprehensive view, and critically compares the performances of aflatoxin analysis methods, encompassing extraction, separation and detection techniques.