High-sensitivity terahertz scanner for detection of aflatoxins in nuts and nut products

Project Summary Abstract Terahertz waves have unique specifications that make them very attractive for non invasivelabel free biosensingThis is because many organic compounds have unique responses to the electromagnetic waves at terahertz frequenciesIn additionterahertz waves can penetrate through many optically opaque environments as well as most of the packaging materials such as plasticpaperetcThese great potentials make terahertz imaging spectroscopy systems an excellent platform for high sensitivityhigh throughputand non destructive detection of aflatoxinswhich can grow in various agricultural food products and cause various chronic health problems if consumedincluding liver cancerAflatoxins have unique spectral characteristics at terahertz frequencieshowever the use of terahertz waves for high throughput and high sensitivity aflatoxin detection in food products did not seem practical before because of the low sensitivity of conventional terahertz scannerswhich suffer from a trade off between the signal to noise ratioSNRand the measurement timeFor instanceto achieve a sufficiently sensitive measurement to detect the maximum allowed aflatoxin contamination level regulated by the Food and Drug AdministrationFDAwith conventional terahertz scannersmore than thousand measurements should be taken on the same sample to reduce the noise of the acquired datawhich increases the measurement time significantlyIn additionmost of the terahertz spectroscopy measurements should be performed in very meticulous wayswhich require specific sample preparation recipes that are not appropriate for field settingsThe proposed research addresses these limitations of conventional terahertz scanning systems and offers a high throughputnon destructiveand highly sensitive aflatoxin scanner that does not require a skilled user to operateThe key innovations that enable such a high performance aflatoxin scanner arethe use of a breakthrough plasmonic terahertz source and detector technology that offers several orders of magnitude higher SNR levels compared to those offered by conventional terahertz devicesthe use of an advanced data analysis algorithm that is capable of direct calculation of aflatoxin concentration regardless of the type and shape of the sample under testAs a resultthe proposed terahertz scanner offers an excellent regulatory tool for high throughputnon destructivenon contact detection of aflatoxins in nuts and processed nut productsminimizing regulatory non compliance risks and providing high quality products to the publicBy the end of the Phase Ia thorough experimental analysis will be completed on aflatoxin tablets and aflatoxincontaminated nuts with a single pixel terahertz scanner prototype to assess the sensitivity and specificity of the proposed scannerIn Phase IIthe aflatoxin scan rate will be boosted by using focal plane detector arrays and the use of the developed multi pixel scanner for detection of aflatoxins will be extended to a wider range of agricultural food productswhile developing a prototype that can be used in realistic field packaging distribution settings Project Narrative High sensitivity and high throughput detection of carcinogen aflatoxins in nuts and processed nut products would have a significant impact on human healthTo achieve this goalwe propose an advanced terahertz scanner that can inspect nuts and processed nut products and detect aflatoxin contamination with concentrations lower than the maximum allowed levels by FDA in a noninvasive and contactless schemeThe key innovations enabling such a high performance aflatoxin scanner are the use of plasmonic terahertz sources and detectorswhich offer significantly larger signal to noise ratios compared to conventional systemsand a novel data analysis algorithmwhich directly calculates aflatoxin concentration regardless of the type and shape of the sample under test