Label-free impedimetric biosensors for the control of food safety-a review

The guarantee of food safety requires fast and accurate control for all contaminants, chemicals and bacteria, which are harmful to human health. Ensuring the safety and quality of food is the main interest both for the food industry and for consumers. In the food industry, the safety of a food product is evaluated through chemical and microbiological analysis: these procedures conventionally use the technique as chromatography, spectrophotometry and electrophoresis that are time-consuming, require highly trained personnel, are expensive and require steps of sample pretreatment, increasing the time of analysis. Consequently, among food and beverage industries, exists a growing demand in biosensing technologies as simple, rapid, accurate, low-cost and portable analytical devices for the monitoring and detection of chemical and microbiological contaminants (toxins, mycotoxins, pathogenic bacteria, pesticides and allergens) that endanger the food safety. Among biosensors, the label-free biosensors, characterised by direct detection of the analyte of interest, exploiting the advantages of an impedimetric transduction technique, seem to be the most promising devices for the future. In the last years, the potential use of Electrochemical Impedance Spectroscopy technique has been widely considered in the biosensor field; it is, in fact, a powerful, non-destructive and informative technique which can be used to study the electrical properties of the sensing device interface and to trace the reactions that occur on it. For these reasons, the application of impedimetric technique as a transduction technology has allowed the label-free detection and sensitive quantification of the bio interaction in different application and thus for the development of food hazards biosensors too. This review provides the current situation in the literature on label-free impedimetric biosensors in food safety.