In the recent decade, the food industry has seen a dramatic increase in research and innovation in the field of nanosensors. From detection of food contaminants and pathogens to food processing and packaging, nanosensors are presenting exciting opportunities and promising technological advancements in the food and beverage industry.
Nanosensors in the food and beverage industry are bioanalytical devices that are created by integrating a combination of nanomaterials and biological receptors into a system design. The transducers in nanosensors are composed of nanomaterials that are physically confined to a nanoscale or are nanostructured surfaces or particles produced because of nanofabrication. The nanomaterials used in these nanosensors may be gold and silver nanoparticles, quantum dots, magnetic nanoparticles, graphene oxide and carbon nanotubes. There are various types of nanosensors and a few common categories are highlighted in this article.
Electrochemical nanosensors
These sensors are used widely and their working is based on the principles of electrochemistry. Electrochemical transducers are usually highly sensitive and quite compatible with state of art nanofabrication technologies. Furthermore, they are robust, economical, simple and require very low maintenance. When nanofabricated chemicals and biological elements react chemically with the target analyte, electrons or ions are either produced or consumed. This change in quantity of ions or electrons can be measured as impedance, current or voltage. Consequently, there are three categories of electrochemical sensing technologies: potentiometry, amperometry and voltammetry.
Amperometric sensors, sometimes called ‘biosensors,’ have been used in the medical field for quite some time now. The nanofabrication approach improves the reliability, cost, and sensitivity of amperometric biosensors, allowing them to be used in areas other than clinical medicine, such as the food and agriculture industry. Voltammetry refers to the measurement of current when the potential is varied in a controlled fashion. An example application of cyclic voltammetry in the food industry is the detection of carbosulfan in rice. Potentiometric sensors assess the potential difference between the working and the reference electrode. The data is collected in the form of the signal produced because of the ion buildup at the ion-sensitive FETs (field-effect-transistors) and at ion-selective electrodes.
Optical nanosensors
Optical nanosensors work by detecting a change in an optical signal. Detection and measurement methodology may include spectroscopy, interferometry, surface plasmon resonance and fluorescence spectroscopy. Through spectroscopic and imaging methods of measurement and detection, fluorescent nanosensing has demonstrated rapid response, great sensitivity and the capacity to achieve high spatial resolution. Gold and silver nanoparticles and quantum dots are inherently fluorescent. In recent research, the surface of Cadmium Selenide (CdSe) and Zinc Sulfide (ZnS) was altered with the silane group and then coupled with the methylacrylate functionalized molecularly imprinted polymer. This resulted in an optosensor based on quantum dots for detecting dicyandiamide in any milk product.
Nanobarcode
Two-dimensional barcodes are widely utilized in visual product verification. However, they are easily tampered with, fabricated and broken. To address these challenges, unique invisible barcodes based on nanoparticles and nano-disks have been created recently to verify the authenticity of different products in the food and beverage industry. A Raman microscope can scan nano-disk barcodes.
Wireless nanosensors
WSN stands for wireless sensor network, which is self-organizing and capable of intelligent decision-making. It is made up of multiple radio-frequency components, microcontrollers, transceivers, micro and nanosensor nodes as well as power sources. In a WSN, sensor versatility and increased network durability have opened up a world of possibilities in many areas including the food industry. Food chain management systems and real-time traceability are two examples of wireless sensor network applications in the food industry.
Toxin detection
Electrochemical nanosensors can play a significant role in detecting toxins in food. There are various research and tests that have successfully identified a wide variety of toxins and carcinogens in a variety of foodstuffs. For instance, in one study, palytoxin was successfully detected in contaminated seafood by using a nanosensor based on carbon nanotubes. Palytoxin is a common marine toxin.
Food pathogen detection
The identification of bacterial genetic material or the entire bacterial cell is the most common method for detecting foodborne pathogens in food products. Nanotechnology enables the use of economical nanosensors in food packaging to sense a variety of pathogenic microbes found in various foods. An example of a nanosensor used in this area is nanobioluminescent spray. This spray contains a variety of magnetic nanoparticles that react with the harmful microorganisms in food to give an easily identified visible color.
Chemicals and pesticide detection
Nanosensors can also be used to detect the presence of pesticides and other chemicals in foodstuffs. There are a large number of examples and nanosensor configurations that can be used for pesticide detection, and they depend on the type of chemical/pesticide. For instance, Organophosphorus and carbamate pesticides have been detected using fluorometric and colorimetric nanosensors coupled with gold nanoparticles. Similarly, nanocomposite biofilm based voltametric nanosensors have been demonstrated to successfully detect particular pesticides.
Quality monitoring of key ingredients
Vitamins and other critical food elements like antioxidants are essential for our bodies, and in processed foods, these vital food components are easily destroyed. Nanosensors can play a significant role in detection of vitamins and other vital elements in the foodstuff to indicate the quality of various processed foodstuffs. For instance, the detection of folic acid and vitamin C in milk samples and fruit juices has been reported using ionic liquid nanocomposites based on nickel oxide nanoparticles and carbon nanotubes.
Conclusion
While nanotechnology is still in its early stages, sophisticated nanomaterials and nanodevices have already begun to revolutionize the food business. Nanosensors are now even being integrated into food packaging to gauge the storage conditions based on various input parameters such as temperature and humidity. Despite the fact that many nanosensors are still in the research stage and awaiting commercialization, the development of nanosensors is a huge leap forward and can significantly help in realizing better products and improving quality in the food industry.
