Honey fraud detection: Use of electrochemical genosensors to determine the safety and quality of honeys

Food fraud has long been an issue for the food and beverage industry. The impacts of these malicious acts have, however, contributed to food safety and quality awareness and the implementation of legislations to minimize their effects on the economy and human health. Nevertheless, with consumers’ increasing interest in and purchase of novel foods, it is difficult to monitor the safety and quality of all products on the market. In the European Union, honey is one of the most adulterated products found on the market. As a natural sweetener, with a rich composition and several health benefits, honey is often consumed as a healthy alternative to sugar. To keep up with product demand, or simply to increase their monetary gain, some producers resort to fraudulent acts such as the adulteration of high-quality honey with lower-quality substances and the mislabelling of its origin and nutritional profile. In this study, a disposable electrochemical genosensor based on the DNA hybridization reaction between two complementary probes of Calluna vulgaris, the heather flower, was developed. These sequences were specifically cut and designed to identify the heather flower DNA in real honey samples. A sandwich format for the DNA target probe was designed using a complementary fluorescein isothiocyanate-labelled DNA signaling probe. To maximize the hybridization reaction, a mixed self-assembled monolayer of the heather-specific DNA capture probe and mercaptohexanol was employed. Using chronoamperometric measurements, the enzymatic amplification of the electrochemical signal was obtained with a concentration range of 0.13 to 2.00 nM. Preliminary results indicate that the developed sensors can detect the presence and estimate the concentration of heather flower DNA in real honey samples and thus be used in honey origin authentication, safety and quality control. As such, the developed genosensors appear as an innovative and cost-effective analytical method to combat honey fraud and promote honey quality and safety.