Food safety is an issue of great concerns for consumers around the world. Despite the fact that the food industry is obliged to follow strict standards regarding the quality control of both their raw materials and their final products, and despite the strict relevant legislation in force in the EU, several food scandals have taken place in recent years. In practice a very small percentage of the foods that end up on our table are tested and the main reason is related to the fact that most of the established methods and procedures are time consuming and of relatively high cost. It is therefore desirable to have available portable, low-cost and easy-to-use devices to test the quality of raw materials and processed products in a short period and use them at all stages between raw materials production and the consumer’s table. To this end, and in the framework of the European Program FOODSNIFFER (FP7-ICT-318319), a portable analytical device was developed for the identification of harmful substances in food, which has the ability to connect wirelessly to any smartphone and transmit the test results directly to the regulatory bodies. The detection is carried out by innovative optoelectronic chips, each of which accommodates in an area of less than 40mm2 10 independent optical sensors in the form of Mach-Zehnder Interferometers, the corresponding light sources, as well as an array of photodiodes, which through a special photonic circuit record the transmission spectra of the sensors. The 10 independent MZI sensors can be modified with ten different biomolecules allowing up to 10 different substances to be simultaneously detected in the same sample. In the framework of the FOODSNIFFER project the chips were modified to allow the simultaneous identification of 4 allergens (cow’s milk casein, soy protein, peanut protein and gluten in samples of rinsing water from dairy industry pipes), 4 mycotoxins (ochratoxin A, aflatoxin B1, fumonisin B1, and deoxynivalenol in different types of beer) or 3 pesticide residues (thiabentazole, imazalil and chloropyrifos in grape and wine samples) in the same sample. In this way, the FOODSNIFFER device is expected to provide a tool for producers of agricultural and livestock products, food traders, regulatory bodies as well as for consumers who want to control the quality of the food they consume and especially for people with food allergies and intolerances to certain food ingredients. For the implementation of the project, researchers of NCSR “Demokritos” from the Program of Nanoelectronics, Photonics and Microsystems of the Institute of Nanoscience and Nanotechnology (INN), and the Laboratory of Immunoassays/Immunosensors of the Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety (INRASTES) collaborated with industrial and academic partners from Greece (ThetaMetrisis SA), Finland (VTT Technical Research Center of Finland), Netherlands (RIKILT Wageningen, LIONIX BV, TRUSTFOOD BV), Germany (Jobst Technologies GmbH), France (EUROFINS), Poland (Jagiellonian University Krakow) and Spain (University of Almeria).
The main strategic objectives of the FOODSNIFFER project are:
FOOSDNIFFER system Realization
The FOODSNIFFER system consists of the miniaturized-portable reader and the biochip that is appropriately biofunctionalized for the detection of the concentration of the targeted analytes. The design and realization of both pillars is presented in detail below:
The FOODSNIFFER was envisioned to monolithically integrate a photonic circuit that surpass current state of the art in terms of size, maturity of integration and analytical performance of PoN systems. Once this target is reached the FOODSNIFEFR chip will be the state of the art in world-wide scale in terms of integration level, size, cost and analytical performance and will be ahead the competition in the race for real miniaturized systems for application of the PoN.
Si chip Design & Development
The FOODSNIFFER chip accommodate ten optoelectronic sensors each one of them comprised of a broad-band light source self-aligned with a waveguide that is engineered to operate as a high resolution Broad-Band Mach-Zehnder Interferometer (BB-MZI)3, a spectrum analyser and a photodetector array for the measurement of the spectral responses and through them the user could monitor the bioreactions. The self-aligned light source and the BB-MZI sensor are illustrated in fig. 1.
The design and simulation work in the FOODSNIFFER project was focused to find solutions for passive optical components required in the FOODSNIFFER chip namely:
The design and simulation work was carried out by LIONIX, NCSR-D, and VTT. LIONIX and VTT focused on the design of spectral components while NCSR-D did designs and simulations on basic waveguide structures and BB-MZI.
Figure The FOODSNIFFER solution represents a holistic approach to food safety monitoring along the entire food chain. Its innovative design has rendered it to a portable system, which permits to non-specialized personnel to operate it with ease and minimal sample preparation and to relay the information in real-time through the Cloud. Ingenious microfluidics and electronics interfacing add to the simplicity of system handling, while specially-designed software allows control of the reader through a smartphone or laptop. Its ease-of-operation though has not limited its accuracy, sensitivity, reliability and costeffectiveness.
Radical photonic engineering has donned its functional core, namely the FOODSNIFFER biochips containing 10 interferometric transducers each with its own light source and the ability for on-chip spectral analysis in a minimal 37mm2-footrpint, with high precision and extremely low limits of detection. Specially-developed biofunctionalization strategies have led to the ability of simultaneous multi-analyte testing (up to 4 different analytes per measurement) and re-usability of the chips up to 15 times.
The great potential of the FOODSNIFFER solution has been exemplified through the simultaneous detection of (a) allergens: bovine casein, peanut protein, soy protein and gluten in rinsing water samples, (b) mycotoxins: ochratoxin A (OTA), or aflatoxin B1 (AFB1), fumonisin B1 (FB1) and deoxynivalenol (DON) in beers, and (c) pesticides: thiabendazole, imazalil, and chlorpyrifos in wine and grape samples, at levels below the EU MRLs within 10-15min. These outstanding performances stand evidence to the ability of the FOODSNIFFER system to become the first high performance PoN system for the detection of harmful substances in any link of the food supply chain, while its competitive advantages and versatility render them to a flexible platform exploitable by all stakeholders along the entire farm-to-fork pathway.