Abstract-Terahertz spectroscopy technology as an innovative technique for food: Current state-of-the-Art research advances

Chao-Hui Feng, Chiko Otani,

https://www.tandfonline.com/doi/abs/10.1080/10408398.2020.1779649?journalCode=bfsn20

With the dramatic development of source and detector components, terahertz (THz) spectroscopy technology has recently shown a renaissance in various fields such as medical, material, biosensing and pharmaceutical industry. As a rapid and noninvasive technology, it has been extensively exploited to evaluate food quality and ensure food safety. In this review, the principles and processes of THz spectroscopy are first discussed. The current state-of-the-art applications of THz and imaging technologies focused on foodstuffs are then discussed. The advantages and challenges are also covered. This review offers detailed information for recent efforts dedicated to THz for monitoring the quality and safety of various food commodities and the feasibility of its widespread application. THz technology, as an emerging and unique method, is potentially applied for detecting food processing and maintaining quality and safety.

Chapter Abstract-Terahertz (THz) application in food contamination detection

 Aifeng Ren,  Adnan Zahid, Xiaodong Yang, Akram Alomainy,  Muhammad Ali Imran, Qammer H. Abbasi

https://digital-library.theiet.org/content/books/10.1049/sbew542e_ch5

This chapter mainly focuses on various sensing technologies that have been employed to detect food and water contamination. It has been found that these conventional sensing technologies appear to be unfeasible and impractical to meet with the challenging growth of population. In this aspect, THz sensing is discussed in detail and deemed to be more effective due to its strong penetration feature, high resolution, and sensitivity to monitor the molecular changes in fruits. This chapter also introduces a novel technique of fruits contamination detection by monitoring MC and observe the transmission and path loss response of fruits. It also investigates an important parameter such as the absorption coefficient and shows some significant results and correlation of MC with transmission response and absorption coefficient. Upon close analysis, these results give meaningful information about the composites present in fruits such as carbohydrates and proteins. Toward the end, this chapter emphasizes on the advancement and development of terahertz technology applications and found that the THz sensing is a promising candidate and has a potential to change a paradigm in the plant science sector.

Abstract-Non-destructive inspection of food and technical oils by terahertz spectroscopy

Mindaugas Karaliūnas, Kinan E. Nasser, Andrzej Urbanowicz, Irmantas Kašalynas, Dalia Bražinskienė, Svajus Asadauskas, Gintaras Valušis

https://www.nature.com/articles/s41598-018-36151-3

Quality control and non-destructive monitoring are of notable interest of food and pharmaceutical industries. It relies on the ability of non-invasive inspection which can be employed for manufacturing process control. We hereby apply terahertz (THz) time-domain spectroscopy as non-destructive technique to monitor pure and degraded oils as well as hydrocarbon chemicals. Significant differences in the spectra of refractive index (RI) and absorption coefficient arising from the presence of ester linkages in the edible and technical oils were obtained. Explicit increase from 1.38 to 1.5 of the RI in all THz spectrum range was observed in hydrocarbons and mono-functional esters with the increase of molar mass. This fact is in contrast of RI dependence on molar mass in multi-functional esters, such as Adipate or vegetable oils, where it is around 1.54. Degradation products, Oleic Acid (OA) and water in particular, lead only to some changes in absorption coefficient and RI spectra of vegetable oils. We demonstrate that complex colloidal and supramolecular processes, such as dynamics of inverse micelles and oil hydrolysis, take part during oil degradation and are responsible for non-uniform dependence of optical properties on extent of degradation.

Abstract-State-of-the-Art in Terahertz Sensing for Food and Water Security – A Comprehensive Review

Aifeng Ren, Adnan Zahid, Dou Fan, Xiaodong Yang, Muhammad AliImran, Akram Alomainy, Qammer H.Abbasi, 


https://www.sciencedirect.com/science/article/abs/pii/S0924224418308768

Background

Recently, there has been a dramatic change in the field of terahertz (THz) technology. The recent advancements in the THz radiation sector considering generation, manipulation and detection have brought revolution in this field, which enable the integration of THz sensing systems into real-world. The THz technology presents detection techniques and various issues, while providing significant opportunities for sensing food and water contamination detection.

Scope and Approach

Many researchers around the world have exploited the potential of invaluable new applications of THz sensing ranging from surveillance, healthcare and recently for food and water contamination detection. The microbial pollution in water and food is one the crucial issues with regard to the sanitary state for drinking water and daily consumption of food. To address this risk, the detection of microbial contamination is of utmost importance, since the consumption of insanitary or unhygienic food can lead to catastrophic illness.

Key Findings and Conclusions

This paper presents a first-time review of the open literature covering the advances in the THz sensing for microbiological contamination of food and water, in addition to state-of-the-art in network architectures, applications and recent industrial developments. With unique superiority, the THz non-destructive detection technology in food inspection and water contamination detection is emerging as a new area of study. With the great progress, some important challenges and future research directions are presented within the field.

Abstract-Detection of foreign bodies in grain with terahertz reflection imaging

Yuying Jiang, Hongyi Ge, Yuan Zhang,


https://www.sciencedirect.com/science/article/pii/S0030402618319909

Foreign bodies embedded in grain are difficult to detect with conventional measurement methods. In this paper, terahertz time-domain spectroscopy (THz-TDS) reflection imaging is proposed as a non-destructive and deeply penetrating technique for detecting the foreign bodies found in wheat grain with different depths below the surface. Image preprocessing and threshold segment algorithm are employed to improve the THz images. In contrast to the behavior of wheat grains, foreign bodies embedded in flour are also detected and analyzed. The results indicate that the THz reflection imaging technology promises to be a useful tool for observing the presence of foreign bodies in grain.

Abstract-Terahertz spectroscopic imaging with discriminant analysis for detecting foreign materials among sausages

Chen Wang, Ruiyun Zhou, Yuxin Huang, Lijuan Xie, Yibin Ying,


https://www.sciencedirect.com/science/article/pii/S0956713518305255

The accurate and rapid detection of foreign materials in food products is essential for ensuring food safety and quality. Terahertz (THz) imaging is an emerging technology for non-destructive detection in food industrial with the advantages of non-ionization and spectroscopic fingerprinting. In this study, we have attempted to explore the effectiveness of THz spectroscopic imaging for foreign material detection in food with complicated compositions. The feasibility of locating contaminations in sausages were demonstrated through typical spectral comparison, spectral classification assisted by principal component analysis and discriminant analysis methods, and one-dimensional scanning spectral analysis. Our imaging results indicated THz spectroscopic imaging has the ability to locate metal contaminations in sausages no matter what part of sausages is as the food matrix. This study will provide new knowledge about foreign material detection in food with complicated compositions and a basis for parameters selection of continuous-wave THz imaging for contamination detection in this case

Abstract-Analytical-performance improvement of laser-induced breakdown spectroscopy for the processing degree of wheat flour using a continuous wavelet transform

Ping Yang, Yining Zhu, Shisong Tang, Zhongqi Hao, Lianbo Guo, Xiangyou Li, Yongfeng Lu, and Xiaoyan Zeng

https://www.osapublishing.org/ao/abstract.cfm?uri=ao-57-14-3730

Quality and safety of food are two of the most important matters in our lives. Wheat is one of the most important products in the modern agricultural processing industry. Issues of mislabeling and adulteration are of increasingly serious concern in the grain market. They threaten the credibility of producers and traders and the rights of the consumers. Therefore, it is very significant to guarantee the processing degree of wheat flour. In this work, two different spectral peak recognition methods, i.e., artificial spectral peak recognition and automatic spectral peak recognition, are carried out to study the adulteration problem in the food industry. Three grades of the processing degree of wheat flour from northern China are classified by laser-induced breakdown spectroscopy (LIBS). To search for an automatic classification model, continuous wavelet transform is used for the automatic recognition of the LIBS spectrum peak. Principal component analysis is used to reduce the collinearity of LIBS spectra data. First, 20 principal components were selected to represent the spectral data for the following discrimination analysis by a support vector machine. The results showed that the classification accuracies of automatic spectral peak recognition are better than those of artificial spectral peak recognition. The classification accuracies of artificial spectral peak recognition and automatic spectral peak recognition are 95.33% and 98.67%; the fivefold cross-validation classification accuracies are 94.67% and 96.67%; and the operation times were 240 min and 2 min, respectively. It can be concluded that LIBS can provide simpler and faster classification without the use of any chemical reagent, which represents a decisive advantage for applications dedicated to rapidly detecting the processing degree of wheat flour and other cereals.

© 2018 Optical Society of America

TERAHERTZ IMAGING SCANNERS FOR FOOD INSPECTION

TeraSense THz high speed line scanner

http://www.ferret.com.au/c/Scitech/TeraHertz-imaging-scanners-for-food-inspection-n2530008

TeraSense presents a range of imaging scanners designed for inspection applications, primarily in the food and agricultural industries. Available in Australia from Scitech , the new TeraHertz (THz) imaging scanners by TeraSense use imaging sensors for non-destructive analysis of the internal structure of objects, making them ideal for food inspection, agricultural inspection and detecting the contents of packages. Results from THz imaging are far superior to infrared, visual, and X-ray inspection methods.

For instance, food manufacturers can use a TeraHertz food scanner to check if a pick-and-place robotic arm has put all candy bars into a cardboard carton. These imagers can see through cardboard or PE packaging and are considered ideal for individual chocolate bars, which can be wrapped in any material, even metal-containing foil, which is impervious to THz rays.

TeraHertz imagers can also be used to check noodle packs for the mandatory seasoning sachet in every pack. Noodle containers are usually made of plastic or synthetic foam (polyfoam), which is transparent to THz waves. The THz food scanner can quickly prompt the conveyor-line operator and indicate if a sachet is missing.

The presence of insects and other foreign objects in food can damage consumer trust as well as the brand in the market. THz imaging systems can easily detect a common housefly through several polyethylene bags, even if total thickness of such PET coating exceeds 20mm. Even metal or plastic debris can be detected inside food packaging with the THz imaging scanners.

TeraSense imaging systems reveal carcinogenic Mycotoxin fungus that contaminates peanuts, corn, hazelnuts, and other grain crops and oil plants. For instance, with the aid of THz imagers, industrial customers can detect any sign of infection such as Aspergillus flavus and Aspergillus parasiticus, which exude the extremely dangerous carcinogen Aflatoxins B1.

For more information, please visit the Scitech website www.scitech.com.au or call (03) 9480 4999.

Terahertz in Bulk Food Inspection

                                                                  Andrew Eddleman, Acquire Automation

http://www.powderbulksolids.com/article/4-Key-Insights-to-Bulk-Food-Inspection-08-29-2017

Detection of contaminants in a bulk flow of product has been, traditionally, very difficult. Usually, this type of inspection is for dry bulk food items, such as grains, beans, vegetables or fruits. These inspections are looking for contaminants such as rocks, wood (usually from pallets), pieces of metal, packaging, plastics, and tape. However other extreme cases may also need to be identified. Below are some insights to inspect for these types of contaminants and what to know when spec’ing out a vision system.

1. Environment: Thermal Concerns, Moisture, Lighting
The environment that these types of inspections play is a major concern when designing a bulk food inspection. Creating a system for a full spray washdown environment is usually mandatory. These inspection systems need to be stainless steel and have either IP67 or IP69K enclosures for all electronics (including lighting). For lighting, this can be a challenge as a custom enclosure will need to be designed or a specialty light will need to be accrued (these are not very common for machine vision lights).  Moisture can also play a factor during the inspection if the product is wet. Moisture can cause light to reflect off product in unpredictable ways, which can affect the overall reliability of the results. Mitigating these effects with software or lighting is almost mandatory in most cases. Heat can also play a factor in the longevity of the equipment. Heat can come from an oven, fryer, or just from an unair-conditioned space (usually during summer months). Since most vision equipment has a max temperature threshold of around 115°F, camera and lighting equipment, along with associated electronics must be vented, insulated, or cooled appropriately.

2. Product Differentiation: Defects, Contamination, Etc.
Since most bulk food products have been exposed to an outside environment at one point and usually have been shipped on pallets and trucks, the variability of what the product can be exposed to is usually high. Many times, contamination from shipping materials used, such as a pallet, bag, or tape, is the main culprit of contamination. At other times, wildlife from the surrounding facility may be of concern. Occasionally, contamination from the processing equipment itself (bolts, nuts, Delrin, etc.) is the problem. Whatever the root cause of the issue is, a wide variety of defects can exist and, therefore, multiple strategies for detection need to be deployed. X-rays can be used to look through products for heavier or denser materials, metal detectors can be deployed to look for metals, and machine vision can look for product detects, as well as surface level contaminants, such as wildlife or packaging material. In each of these cases, the technology used is often chosen by the abundance of the type of problem and the relative cost of the equipment. For example, vision systems can be a low-cost alternative to metal detectors or x-rays, but if detecting contaminants under a product is warranted, then traditional machine vision would not be up to the challenge.

3. Analytics: Tracking, Reject, and Data Collection
With the advent of Factory 4.0 and advanced manufacturing, more and more data is being required to detect, reject, and characterize contaminants in product. Whether that is from wildlife for “extermination” purposes or from packaging for transportation improvements. Tracking to a reject point is usually crucial for any inspection equipment. For bulk food, this can be tracking to a gap in the conveyor transport so that a blow-off mechanism can be utilized, a pull nose conveyor or just a simple alarm that stops the transport mechanism. When the product or contaminant is rejected from the bulk-flow the failure is either recorded in a database or alarms an operator to the condition. Data analytics then can be utilized to track the overall progress of operations (an example would be a scada system) or provide more advanced analytics about the process and give insights about future improvements.

4. Advanced Quality Inspections: 3D, Spectral Imaging, Terahertz Imaging, and More
New technologies are being introduced every year to increase the quality of bulk food inspections. 3D technology can be utilized for counting operations as well quality inspections such as volume measurements. Spectral and hyperspectral imagers can detect defects in products like sugary ends in potatoes and bruises in apples. Terahertz cameras can be used to eliminate the need for X-rays in inspection and to detect defects or contaminants hid by packaging or embedded in the product itself. Increasingly, this advanced inspection equipment is being utilized by quality departments to do inline measurements during production or detecting common defects in novel ways.
    
Andrew Eddleman is applications engineer at Acquire Automation, Fishers, IN. He has more than 10 years of experience in machine vision design, developing everything from hardware designs to software programming. In his current role as an, he works with customers across the country on a diverse array of machine vision applications such as 3D technology and Deep Learning. For more information, visit acquireautomation.com.

Abstract-A Non-destructive Terahertz Spectroscopy-Based Method for Transgenic Rice Seed Discrimination via Sparse Representation

Xiaohua Hu, Wenhui Lang, Wei Liu, Xue Xu, Jianbo Yang, Lei Zheng

https://link.springer.com/article/10.1007%2Fs10762-017-0392-z

Terahertz (THz) spectroscopy technique has been researched and developed for rapid and non-destructive detection of food safety and quality due to its low-energy and non-ionizing characteristics. The objective of this study was to develop a flexible identification model to discriminate transgenic and non-transgenic rice seeds based on terahertz (THz) spectroscopy. To extract THz spectral features and reduce the feature dimension, sparse representation (SR) is employed in this work. A sufficient sparsity level is selected to train the sparse coding of the THz data, and the random forest (RF) method is then applied to obtain a discrimination model. The results show that there exist differences between transgenic and non-transgenic rice seeds in THz spectral band and, comparing with Least squares support vector machines (LS-SVM) method, SR-RF is a better model for discrimination (accuracy is 95% in prediction set, 100% in calibration set, respectively). The conclusion is that SR may be more useful in the application of THz spectroscopy to reduce dimension and the SR-RF provides a new, effective, and flexible method for detection and identification of transgenic and non-transgenic rice seeds with THz spectral system

Designing sensors to detect foreign bodies in food

CAPTION Image obtained with this technology in which there can be seen, on a slice of sausage, plastics, metals and splinters of glass of different sizes and shapes. CREDIT / NUP/UPNA-Public University of Navarre

ELHUYAR FUNDAZIOA

https://www.eurekalert.org/pub_releases/2017-03/ef-dst033117.php

These devices are based on terahertz technology, a band in the electromagnetic spectrum located between the microwaves (which mobile phones and TVs need to function) and the infrared waves. This terahertz band is the last unexplored region of the electromagnetic spectrum owing to the difficulty in generating and detecting waves of this type. Yet one of the fields in which terahertz offer huge technological potential is in the sensing of substances and materials. This is due to the fact that nearly all the molecules display a characteristic footprint on this band and this allows them to be distinguished and identified.

"Seeing" inside substances

"Terahertz radiation is capable of penetrating a huge range of objects and substances, so they make it possible to 'see' what is inside them," explained Juan Carlos Iriarte. "In the same way, the reflection of terahertz waves varies according to the material or body they impact upon, and this provides images depending on the power and phase of the wave received."

The sensors developed in this project are used firstly to detect foreign bodies present in food products, such as sliced meat and vegetables. "Metals, including corrosion-resistant ones, paper, insects, plastics or glass can be found among these foreign bodies," pointed out the NUP/UPNA researcher. Secondly, the sensors can be used to identify, in real time, microorganisms belonging to the main, common pathogenic strains that may be present in perishable foodstuffs, and to carry out microorganism counts.

The researchers in this project have designed a device which is a miniaturized blend of transmitter and receiver and which undertakes to detect the radiation reflected in the terahertz frequency range, caused by a foreign body or by the chemical product one is intending to study. "In the first case, that of a foreign body, the radiation is in proportion to its morphology, and, in the second, when a chemical product is involved, its molecular composition is obeyed allowing it to be unequivocally identified because each one has its own spectral radiation footprint," added Juan Carlos Iriarte. The spectral signature of objects and substances is very different between one case and another and that is why detection is much more simple and leads to fewer false alarms, according to the authors of this research.

"The system for capturing images in terahertz constitutes a great advance in this field, as there are no similar devices devoted to inspection in the food sector, either nationally or internationally," concluded Juan Carlos Iriarte.

This terahertz-based technology is already being used in the field of security to non-intrusively obtain images of concealed weapons. In actual fact, the NUP/UPNA's Antennas Group is actively participating in applying this technological development in the sector.

###

This development has been possible thanks to a project funded by nearly 300,000 euros by the Ministry of the Economy, Industry and Competitiveness as part of the State Plan for Scientific and Technical Research and Innovation 2013-2016.

Spain: New sensors to detect foreign bodies in food

http://www.freshplaza.com/article/172831/Spain-New-sensors-to-detect-foreign-bodies-in-food

Researchers from the Public University of Navarre (UPNA) and the Navarre-based company Anteral SL, have designed a new system of sensors intended to improve quality controls in the agro-food sector.

These devices make it possible to detect foreign bodies, such as metal, paper, insects, plastic or glass, in a food production chain and identify pathogenic microorganisms in real time. This development, based on terahertz technology, has been possible thanks to a project funded with almost 300,000 Euro by the Spanish Ministry of Economy, Industry and Competitiveness in the framework of the 2013-2016 State Plan for Scientific and Technical Research and Innovation.

The project, called TeraFOOD, was developed by the UPNA's Research Group, formed by Íñigo Ederra Urzainqui, Cebrián García González, Ramón Gonzalo García, Juan Carlos Iriarte Galarregui (head researcher), Carlos Quemada Mayoral and Jorge Teniente Vallinas, working in partnership with the firm Anteral SL, which is specialised in the design of antennas and terahertz technology and has acted as coordinator of the initiative.

These devices are based on terahertz technology, a band of the electromagnetic spectrum located between the microwaves (those needed by mobile phones or TVs) and the infrared waves. The terahertz band is the last unexplored region of the electromagnetic spectrum, due to the difficulty of generating and detecting this type of wave; however, one of the fields where terahertz offers enormous technological potential is in the sensing of substances and materials. This is because almost all molecules have a characteristic trace in this band, which makes it possible to distinguish and identify them.

"The system is a great step forward in this field, since there are no similar devices intended for the carrying out of inspections in the agro-food sector, neither nationally nor internationally," concludes Juan Carlos Iriarte.

This terahertz-based technology is already being used in the area of security to obtain non-intrusive images of hidden weapons. In fact, the UPNA Antenna Group actively participates in the application of this technological development in this sector.

Terahertz radiation: A useful source for food safety

The principle of the emitter: An extremely short laser pulse drives electrons out of a magnetic metal layer into a non-magnetic one. The important point is that there are two types of electrons which differ in spin (thick light blue arrows) and in number (length of the thick arrow). In the non-magnet, these electrons are deflected up or down, depending on the direction of their spin. The resulting short pulse of current along the red arrow generates a terahertz pulse. CREDIT FHI/Nature Photonics 2016

A compact and low-cost emitter generates light across the entire terahertz spectrum

MAX-PLANCK-GESELLSCHAFT

http://www.eurekalert.org/pub_releases/2016-06/m-tra061716.php

An effective and less expensive tool for the inspection of food and drugs could soon be a reality. Scientists from the Fritz Haber Institute of the Max Planck Society in Berlin have been working with national and international partners to develop a conceptually new source of terahertz radiation. The innovation makes it much easier to generate this radiation, which is well suited to the analysis of soft materials and could therefore be more widely used in the food and pharmaceutical industry in future.

Terahertz waves lie in the frequency range between from about 0.3 to 30 terahertz in the electromagnetic spectrum - between microwaves and infrared light. They are useful for analyzing organic materials, as they can penetrate things like textiles and plastics while also being characteristically absorbed by many pharmaceuticals. Unlike X-rays or other sources of radiation, terahertz radiation is also completely harmless for the body.

A large bandwidth for the food and pharmaceutical industry

"Our method of generating terahertz radiation makes applications possible that were previously too costly for such sources," says Tobias Kampfrath, leader of the Terahertz Physics Research Group at the Fritz Haber Institute, which spearheaded the development process. The terahertz source which Kampfrath's team and their partners in Mainz, Greifswald and Jülich, as well as in the US, Sweden and France, have now presented is the first to generate the entire bandwidth of terahertz radiation at relatively low cost. This could be extremely useful for the inspection of food and drugs, as analyses with broadband terahertz radiation target numerous substances and thus deliver more meaningful results. Currently, equipment which can generate the entire spectrum of terahertz radiation is still big and expensive, as it relies on very powerful lasers.

"Our emitter generates the entire spectrum from 1 to 30 terahertz and is therefore also suitable for use as a table-top emitter. Not only that; it is more energy efficient, easier to operate and cheaper to manufacture than former sources," according to Tom Seifert, doctoral student at the Fritz Haber Institute. "We anticipate that it will quickly find use on a broad basis."

A short pulse of current turns a metallic bilayer into an antenna

The source is powered by a compact femtosecond laser, which generates 80 million ultrashort flashes of light per second. It excites the actual emitter, which resembles a solar cell. However, it consists of two metal layers, one magnetic and one non-magnetic, each just three nanometers thick, which are grown on a glass substrate. When an ultrashort laser pulse hits the material, it generates a current burst, turning the metallic bilayer into a type of antenna emitting electromagnetic waves with terahertz frequencies.

"The emitter works so well because, in addition to the charge of the flowing electrons, we also use their spin," explains Tom Seifert. The spin of an electron is a magnetic property which can have two distinct values. It causes the current to behave differently in magnetic than in non-magnetic metals. First, the laser light excites different numbers of electrons with the two possible spin directions in the magnetic layer. Then, the current flows into the non-magnetic layer, where the electrons are deflected into opposite directions depending on their spin. This produces a current perpendicular to the electrons' original direction of movement. It is precisely this current burst that then generates the terahertz pulse. Eventually, because the metallic bilayer is extremely thin, the electromagnetic radiation is barely weakened at all on its way out of the metal, as would be the case in a thicker layer.

###

Original publication

T. Seifert, S. Jaiswal, U. Martens, J. Hannegan, L. Braun, P. Maldonado, F. Freimuth, A. Kronenberg, J. Henrizi, I. Radu, E. Beaurepaire, Y. Mokrousov, P. M. Oppeneer, M. Jourdan, G. Jakob, D. Turchinovich, L. M. Hayden, M. Wolf, M. Münzenberg, M. Kläui und T. Kampfrath

Efficient metallic spintronic emitters of ultrabroadband terahertz radiation

Nature Photonics, 23 May 2016; DOI: 10.1038/NPHOTON.2016.91

Abstract-Discrimination of Moldy Wheat Using Terahertz Imaging Combined with Multivariate Classification

Yuying Jiang,   Hongyi Ge,   Feiyu Lian,   Yuan Zhang and  Shanhong Xia  

RSC Adv., 2015, Accepted Manuscript

DOI: 10.1039/C5RA15377H
Received 02 Aug 2015, Accepted 17 Oct 2015
First published online 19 Oct 2015
http://pubs.rsc.org/en/content/articlelanding/2015/ra/c5ra15377h#!divAbstract

Terahertz (THz) imaging was employed to develop a novel method for discriminating wheat of varying states of moldiness. Spectral data, in the range of 0.1–1.6 THz, were extracted from regions of interest (ROIs) in the THz images. Principal component analysis (PCA) was used to evaluate the spectral data and determine the cluster trend. Six optimal frequencies were selected by implementing PCA directly for each image’s ROI. Classification models for moldy wheat identification were established using the support vector machine (SVM) method, a partial least-squares regression analysis, and the back propagation neural network method. The models developed from these methods were based on the full and optimal frequencies, using the top three principal components as input variables. The PCA-SVM method achieved a prediction accuracy of over 95%, and was implemented at every pixel in the images to visually demonstrate the moldy wheat classification method. Our results indicate that THz imaging combined with chemometric algorithms is efficient and practical for the discrimination of moldy wheat.

Abstract-High-performance sub-terahertz transmission imaging system for food inspection.

Ok G1, Park K1, Chun HS2, Chang HJ1, Lee N1, Choi SW1.
http://www.ncbi.nlm.nih.gov/pubmed/26137392

Unlike X-ray systems, a terahertz imaging system can distinguish low-density materials in a food matrix. For applying this technique to food inspection, imaging resolution and acquisition speed ought to be simultaneously enhanced. Therefore, we have developed the first continuous-wave sub-terahertz transmission imaging system with a polygonal mirror. Using an f-theta lens and a polygonal mirror, beam scanning is performed over a range of 150 mm. For obtaining transmission images, the line-beam is incorporated with sample translation. The imaging system demonstrates that a pattern with 2.83 mm line-width at 210 GHz can be identified with a scanning speed of 80 mm/s.

SpectroscopyNOW-Last Month's Most Accessed Feature: NMR spectroscopy rides in: Detects horse fat

http://www.spectroscopynow.com/nmr/details/highlight/13a30421911/Last-Months-Most-Accessed-Feature-NMR-spectroscopy-rides-in-Detects-horse-fat.html

Neigh, neigh and thrice neigh

The presence of horsemeat in adulterated meat products can now be revealed quickly and easily using nuclear magnetic resonance (NMR) spectroscopy to test the fat profile of the food without the need for complication and long-winded genetic analysis.

A team at the Institute of Food Research in Norwich, UK, have worked with Oxford Instruments to develop a fast, and inexpensive alternative to DNA testing for distinguishing horse meat from beef based on the profile of the meat's fat content.

Although both grass-eating herbivores, horses (Equus ferus caballus) and cattle (Bos taurus) have different digestive systems and as such the fatty constituents of the meat from these two species is rather different, providing a simple way to distinguish between the two in mislabelled or unadulterated meat products. NMR spectroscopy takes just ten minutes to distinguish between raw horse meat and beef and while initially funded by Innovate UK and the Biotechnology and Biological Sciences Research Council (BBSRC) has now been tested in an industrial setting at the premises of a leading meat processor. The team is now developing profiles for other meat fats, including pork and lamb.

Equine adulteration

Back in 2013 scandal rocked the food industry in the UK as it was discovered that food manufacturers and supermarkets were selling purportedly beef products in which horse meat had been used instead of beef. Millions of pounds worth of food was removed from supermarket shelves and the crisis brought urgency to understanding just how vulnerable the meat supply chain is to food fraud and perhaps threats to public health. High on the agenda was the lack of appropriate assays and tests other than slow and costly DNA testing.

Trot along

The IFR and Oxford Instruments developed "Pulsar", a high resolution bench-top NMR spectrometer that is far smaller and a lot less expensive than conventional NMR spectrometers. Moreover, Pulsar is simpler to use and requires none of the sophisticated cryogenics for super-cooled magnets in high-power instruments. A meat test with Pulsar involved shaking approximately one gram of meat in an organic solvent and then a few minutes of data acquisition. The cheminformatics software that analyses the spectral lines and flags the sample as beef or horse was developed at IFR.

"It's a stroke of luck really that some of the most important meats turn out to have fat signatures that we can tell apart so easily with this method," explains Kate Kemsley. "It's been very satisfying to see results from a real industrial setting sit right on top of those we generated in our two labs. We think this testing method should work well at key points in the supply chain, say at meat wholesalers and processors."

Abstract-Feasibility of Terahertz Time-Domain Spectroscopy to Detect Tetracyclines Hydrochloride in Infant Milk Powder

Jianyuan Qin , Lijuan Xie , and Yibin Ying

Anal. Chem., Just Accepted Manuscript

DOI: 10.1021/ac503212q

Publication Date (Web): October 27, 2014

Copyright © 2014 American Chemical Society

http://pubs.acs.org/doi/abs/10.1021/ac503212q

We report the use of terahertz time-domain spectroscopy (THz-TDS) to detect tetracyclines hydrochloride (TCsH) in infant milk powder for the first time. Four kinds of TCsH exhibited their unique spectral features in the region of 0.3-1.8 THz. The main spectral features of these TCsH were still detectable when mixed with infant milk powder with concentrations at 1%-50%, even in the ternary mixtures. The results from chemometrics analysis showed that qualitative and quantitative detection of TCsH in infant milk powder could be successfully achieved. The residual predictive deviation (RPD) values of all these TCsH models were all higher than 2, indicating these models were considered good, and could be used in screening purposes. The RPD values of TCH, DTCH and CTCH models were higher than 3, which were considered excellent for prediction purposes. These preliminary results indicated that THz-TDS combined with chemometrics analysis was suitable for detecting the presence of TCsH residues in a food matrix.