Food Quality Monitoring Research Articles

Recent Advances and Applications of External Cavity-QCLs towards Hyperspectral Imaging for Standoff Detection and Real-Time Spectroscopic Sensing of Chemicals

External-cavity quantum cascade lasers (EC-QCL) are now established as versatile wavelength-tunable light sources for analytical spectroscopy in the mid-infrared (MIR) spectral range. We report on the realization of rapid broadband spectral tuning with kHz scan rates by combining a QCL chip with a broad gain spectrum and a resonantly driven micro-opto-electro-mechanical (MOEMS) scanner with an integrated diffraction grating in Littrow configuration. The capability for real-time spectroscopic sensing based on MOEMS EC-QCLs is demonstrated by transmission measurements performed on polystyrene reference absorber sheets, as well as on hazardous substances, such as explosives. Furthermore, different applications for the EC-QCL technology in spectroscopic sensing are presented. These include the fields of process analysis with on- or even inline capability and imaging backscattering spectroscopy for contactless identification of solid and liquid contaminations on surfaces. Recent progress in trace detection of explosives and related precursors in relevant environments as well as advances in food quality monitoring by discriminating fresh and mold contaminated peanuts based on their MIR backscattering spectrum is shown.

Rapid electrochemical screening methods for food safety and quality

This paper presents some examples of rapid, simple and cost effective screening methods that can be realized by the use of Screen Printed Electrodes (SPEs) coupled with portable and cheap instrumentation, for the monitoring of food safety and quality. When necessary, these SPEs have been modified with nanomaterials in order to improve their performance and then their analytic characteristics. Arsenic detection, for example, has been obtained with SPEs modified with of a composite of nanostructured Carbon Black and Au nanoparticles, while for the pesticide detection the SPEs were modified with Prussian Blue nanoparticles in addition to the enzyme Butyrylcholinesterase. In the case of immunosensors, a high sensitivity has been obtained making the entire immunological chain to happen on the surface of magnetic beads (MBs), finally collected on the surface of screen printed arrays with the aid of magnets located just under the working electrodes. Application to real samples demonstrates the effectiveness of such approaches.

Bullishness at Pittcon

Instrument makers at the Pittsburgh Conference on Analytical Chemistry & Applied Spectroscopy (Pittcon) in Atlanta last week were generally optimistic about business growth in 2016. “The market appears to be solid now,” said Christopher O’Connell, the new CEO of Waters Corp., a chromatography and mass spectrometry specialist. He expects continued strong demand from China—even though the overall economy there is slowing—because of increased spending on instruments for environmental and food-quality monitoring. Dan Shine, senior vice president of Thermo Fisher Scientific and a member of C&EN’s advisory board, concurred and added that greater availability of government research funding in the U.S. and EU should also help instrument and consumable sales in 2016. Bruker CEO Frank Laukien expects demand from life sciences customers to “be decent, but not spectacular.” At Pittcon, Waters and Thermo Fisher introduced new kits aimed at reducing the burden of sample preparation for proteomics researchers. Start-up firm 908

Diazonium-based impedimetric aptasensor for the rapid label-free detection of Salmonella typhimurium in food sample

Fast and accurate detection of microorganisms is of key importance in clinical analysis and in food and water quality monitoring. Salmonella typhimurium is responsible for about a third of all cases of foodborne diseases and consequently, its fast detection is of great importance for ensuring the safety of foodstuffs.We report the development of a label-free impedimetric aptamer-based biosensor for S. typhimurium detection. The aptamer biosensor was fabricated by grafting a diazonium-supporting layer onto screen-printed carbon electrodes (SPEs), via electrochemical or chemical approaches, followed by chemical immobilisation of aminated-aptamer. FTIR-ATR, contact angle and electrochemical measurements were used to monitor the fabrication process. Results showed that electrochemical immobilisation of the diazonium-grafting layer allowed the formation of a denser aptamer layer, which resulted in higher sensitivity. The developed aptamer-biosensor responded linearly, on a logarithm scale, over the concentration range 1×101 to 1×108CFUmL−1, with a limit of quantification (LOQ) of 1×101CFUmL−1 and a limit of detection (LOD) of 6CFUmL−1. Selectivity studies showed that the aptamer biosensor could discriminate S. typhimurium from 6 other model bacteria strains. Finally, recovery studies demonstrated its suitability for the detection of S. typhimurium in spiked (1×102, 1×104 and 1×106CFUmL−1) apple juice samples.

Plant polymer as sensing material: Exploring environmental sensitivity of dielectric properties using interdigital capacitors at ultra high frequency

An interdigital capacitor (IDC) system was designed in order to provide a controlled high exposure (high surface/thickness ratio) to the environmental atmosphere of a sensing layer of which the dielectric properties were identified by a finite element method simulation and validated using a common parallel plate capacitor technique. The dielectric properties of one of the most sensitive and widely available plant polymers in nature: wheat gluten (WG) proteins were determined at ultra high frequency (500MHz–1000MHz) at 25°C and at two different values of relative humidity (RH). Increasing relative humidity from 20% RH to 80% RH increased the dielectric loss and permittivity of wheat gluten from 0.39±0.01 to 0.84±0.02 and from 5.01±0.06 to 7.07±0.18, respectively. This effect was discussed in the light of wheat gluten composition (constituting amino acids), structure (high molecular weight, proteins unfolding and mobility) and water content (adsorbed water-bonding state). In addition to RH, two other analytes known as food quality markers, carbon dioxide (CO2) and ethanol were studied in terms of sensitivity. The sensitivities of 10.0±0.4 fF/%RH, 31.38±0.06 fF/%CO2 and 25.50±0.05 pF/%ethanol obtained should pave the way for the development of innovative green radio frequency identification (RFID) tags using renewable, cheap and biodegradable plant polymers as gas and vapor sensors. The sensors are intended to be interfaced to low-cost, ultra high frequency, passive, RFID tags for monitoring food quality and freshness volatile markers in packaging headspace.

Image analysis operations applied to hyperspectral images for non-invasive sensing of food quality – A comprehensive review

Image analysis involving mathematical, statistical and software programming approaches are the essential elements of any computer-integrated hyperspectral imaging systems. The theoretical and practical issues associated with the development, analysis, and application of essential image processing algorithms are explored in order to exploit hyperspectral imaging for application to food quality evaluations. The breadth of different image processing approaches adopted over the years in attempting to implement hyperspectral imaging for food quality monitoring was surveyed. Firstly, the fundamental configurations and working principles of hyperspectral systems, as well as the basic concept and structure of hyperspectral data, were described and explained. The understanding of different approaches used during image acquisition, data collection and visualisation were examined. Strategies and essential image processing routines necessary for making the appropriate decision during detection, classification, identification, quantification and/or prediction processes are presented. Examples and figures were selected to reinforce the main approach of each analysis algorithm applied in different agro-food products to answer the question “What does the user want to see in the target food samples?” The theoretical background for each algorithm was beyond the scope of this article thus only essential equations were addressed. The literature presented clearly revealed that hyperspectral imaging systems have gained a rapid interest from researchers to display the chemical structure and related physical properties of numerous types of food stuffs and hyperspectral imaging systems are expected to gain more considerably more potential and application in food processing and engineering plants.

Encapsulating quantum dots with amino functionalized mesoporous hollow silica microspheres for the sensitive analysis of formaldehyde in seafood

We developed a hybrid fluorescent material using amino functional mesoporous hollow silica microspheres (MHSM) encapsulated with CdTe quantum dots (QDs).

Food quality and safety monitoring using gas sensor array in intelligent packaging

Purpose This paper aims to study different possibilities for implementing easy-to-use and cost-effective micro-systems to detect and trace expelled gases from rotten food. The paper covers various radio-frequency identification (RFID) technologies and gas sensors as the two promoting feasibilities for the tracing of packaged food. Monitoring and maintaining quality and safety of food in transport and storage from producer to consumer are the most important concerns in food industry. Many toxin gases, even in parts per billion ranges, are produced from corrupted and rotten food and can endanger the consumers’ health. To overcome the issues, intelligent traceability of food products, specifically the packaged ones, in terms of temperature, humidity, atmospheric conditions, etc., has been paid attention to by many researchers.

Application of Iron Oxide as a pH-dependent Indicator for Improving the Nutritional Quality.

Acid food indicators can be used as pH indicators for evaluating the quality and freshness of fermented products during the full course of distribution. Iron oxide particles are hardly suspended in water, but partially or completely agglomerated. The agglomeration degree of the iron oxide particles depends on the pH. The pH-dependent particle agglomeration or dispersion can be useful for monitoring the acidity of food. The zeta potential of iron oxide showed a decreasing trend as the pH increased from 2 to 8, while the point of zero charge (PZC) was observed around at pH 6.0-7.0. These results suggested that the size of the iron oxide particles was affected by the change in pH levels. As a result, the particle sizes of iron oxide were smaller at lower pH than at neutral pH. In addition, agglomeration of the iron oxide particles increased as the pH increased from 2 to 7. In the time-dependent aggregation test, the average particle size was 730.4 nm and 1,340.3 nm at pH 2 and 7, respectively. These properties of iron oxide particles can be used to develop an ideal acid indicator for food pH and to monitor food quality, besides a colorant or nutrient for nutrition enhancement and sensory promotion in food industry.

Intelligent Packaging Systems: Sensors and Nanosensors to Monitor Food Quality and Safety

The application of nanotechnology in different areas of food packaging is an emerging field that will grow rapidly in the coming years. Advances in food safety have yielded promising results leading to the development of intelligent packaging (IP). By these containers, it is possible to monitor and provide information of the condition of food, packaging, or the environment. This article describes the role of the different concepts of intelligent packaging. It is possible that this new technology could reach enhancing food safety, improving pathogen detection time, and controlling the quality of food and packaging throughout the supply chain.

Responsive Food Packaging: Recent Progress and Technological Prospects.

Responsive food packaging is an emerging field in food packaging research and the food industry. Unlike active packaging, responsive packaging systems react to stimuli in the food or the environment to enable real time food quality and food safety monitoring or remediation. This review attempts to define and clarify the different classes of food packaging technologies. Special emphasis is given to the description of responsive food packaging including its technical requirements, the state of the art in research and the current expanding market. The development and promises of stimuli responsive materials in responsive food packaging are addressed, along with current challenges and future directions to help translate research developments into commercial products.

High Throughput Multispectral Image Processing with Applications in Food Science

Recently, machine vision is gaining attention in food science as well as in food industry concerning food quality assessment and monitoring. Into the framework of implementation of Process Analytical Technology (PAT) in the food industry, image processing can be used not only in estimation and even prediction of food quality but also in detection of adulteration. Towards these applications on food science, we present here a novel methodology for automated image analysis of several kinds of food products e.g. meat, vanilla crème and table olives, so as to increase objectivity, data reproducibility, low cost information extraction and faster quality assessment, without human intervention. Image processing’s outcome will be propagated to the downstream analysis. The developed multispectral image processing method is based on unsupervised machine learning approach (Gaussian Mixture Models) and a novel unsupervised scheme of spectral band selection for segmentation process optimization. Through the evaluation we prove its efficiency and robustness against the currently available semi-manual software, showing that the developed method is a high throughput approach appropriate for massive data extraction from food samples.

Development of novel wireless sensor for food quality detection

In this paper we present a wireless sensor for the monitoring of food quality. We integrate sensing capability into ultrahigh frequency (UHF) radio-frequency identification (RFID) tags through the relationship between the physical read-range and permittivity of the object we label with the RFID tags. Using the known variations of food permittivity as a function of time, we can detect the contamination time at which a food product becomes unacceptable for consumption based on the measurement of read-range with the as-designed sensing tags. This low-cost UHF RFID passive sensor was designed and experimentally tested on beef, pork, and cheese with the same storage conditions as in supermarkets. The agreement between the experimental and simulation results show the potential of this technique for practical application in food-quality tracking.

ZnO Nanostructures with Different Morphologies and Their Combinatorial Optimization with Graphene Oxide for Gas Sensor Properties

Consumer concerns on food safety and quality are increasing worldwide. Without opening the package of food products, collecting information about freshness of the product is desirable. Therefore, an electronic nose device consisting of multiple gas sensors can be utilized for rapid monitoring of food quality and freshness at low cost. Such multiple gas sensors, i.e array structure can provide selective detection and identification of various compounds by linking gas responses to signal process. Gas sensors based on chemical reaction on the surface of semiconducting metal oxides are readily available commercially. Common material of the metal oxide sensor is tin oxide doped with a small amount of a catalytic metal such as palladium or platinum. The improvement of gas sensing performance such as low operating temperature as well as selective and sensitive detection can be obtained by investigating potential oxides with controlled morphologies at the nanoscale and their composite structures. Among various semiconducting materials, ZnO is an excellent candidate for gas sensor applications. In addition, many methods can be utilized to fabricate various ZnO nanostructures. Solution process can be simple and effective bottom-up path to construct hierarchical ZnO nanostructures on various substrates. Therefore, we investigated a solution method as controlling the morphology of ZnO nanostructures by applying DC and AC bias and by selecting different precursors. ZnO nanorods structure was synthesized using zinc nitrate hexahydrate and HMT (hexamethylenetetramine) in aqueous solution. The use of zinc chloride instead of zinc nitrate hexahydrate for zinc precursor, nanoflake structure was successfully fabricated where zinc chloride serves as a capping ion to prevent isotropic growth. With applying external voltage during solution growth, ZnO nanorods became agglomerate structures and the degree of agglomerates varies depending on the range of external bias. Various ZnO nanostructures have been analyzed with SEM, XRD and UV-visible. Figure 1 shows one example of morphological control of ZnO nanostructures according to applying bias and precursors. The change of morphologies showed different degree of orientation of the structures by XRD result. Gas sensing response was measured to extract characteristic feature at different ZnO morphologies. Elevated operating temperature approaching 200 – 300°C from ZnO gas sensor can be lowered by combining graphene oxide (GO). Various combinatorial structures from ZnO and GO were explored. Detailed discussion on gas sensing properties and their mechanisms will be given. Figure 1

Enhanced Radio Frequency Biosensor for Food Quality Detection Using Functionalized Carbon Nanofillers

This paper outlines an improved design of inexpensive, wireless and battery free biosensors for in situ monitoring of food quality. This type of device has an additional advantage of being operated remotely. To make the device, a portion of an antenna of a passive 13.56 MHz radio frequency identification (RFID) tag was altered with a sensing element composed of conductive nanofillers/particles, a binding agent, and a polymer matrix. These novel RFID tags were exposed to biogenic amine putrescine, commonly used as a marker for food spoilage, and their response was monitored over time using a general-purpose network analyzer. The effect of conductive filler properties, including conductivity and morphology, and filler functionalization was investigated by preparing sensing composites containing carbon particles (CPs), multiwall carbon nanotubes (MWCNTs), and binding agent grafted-multiwall carbon nanotubes (g-MWCNTs), respectively. During exposure to putrescine, the amount of reflected waves, frequency at resonance, and quality factor of the novel RFID tags decreased in response. The use of MWCNTs reduced tag cutoff time (i.e., faster response time) as compared with the use of CPs, which highlighted the effectiveness of the conductive nanofiller morphology, while the addition of g-MWCNTs further accelerated the sensor response time as a result of localized binding on the conductive nanofiller surface. Microstructural investigation of the film morphology indicated a better dispersion of g-MWCNTs in the sensing composite as compared to MWCNTs and CPs, as well as a smoother texture of the surface of the resulting coating. These results demonstrated that grafting of the binding agent onto the conductive particles in the sensing composite is an effective way to further enhance the detection sensitivity of the RFID tag based sensor.

Development and Evaluation of a Smart Packaging for the Monitoring of Ricotta Cheese Spoilage

Colorimetric Smart packaging pH indicator offers a potential use that could allow consumer evaluation of the food quality. In this study, it was developed a film based on chitosan, gelatin, PVA and red cabbage extract for food quality monitoring. Films were characterized by Thickness and swelling index. Proofof-Concept application tests were conducted with Ricotta cheese for evaluated the potential use in the food spoilage. The results show that indicator film has high hydration capacity and during application in cheese, the film did not visually indicated color change after 7 days refrigeration storage.

Quantification of whey in fluid milk using confocal Raman microscopy and artificial neural network

In this work, we assessed the use of confocal Raman microscopy and artificial neural network as a practical method to assess and quantify adulteration of fluid milk by addition of whey. Milk samples with added whey (from 0 to 100%) were prepared, simulating different levels of fraudulent adulteration. All analyses were carried out by direct inspection at the light microscope after depositing drops from each sample on a microscope slide and drying them at room temperature. No pre- or posttreatment (e.g., sample preparation or spectral correction) was required in the analyses. Quantitative determination of adulteration was performed through a feed-forward artificial neural network (ANN). Different ANN configurations were evaluated based on their coefficient of determination (R2) and root mean square error values, which were criteria for selecting the best predictor model. In the selected model, we observed that data from both training and validation subsets presented R2>99.99%, indicating that the combination of confocal Raman microscopy and ANN is a rapid, simple, and efficient method to quantify milk adulteration by whey. Because sample preparation and postprocessing of spectra were not required, the method has potential applications in health surveillance and food quality monitoring.

Use of volatile organic compounds and physicochemical parameters for monitoring the post-harvest ripening of imported tropical fruits

The trade of fresh fruits from tropical countries has steadily increased over the past decades, but limited familiarity of consumers with these products has limited their introduction in worldwide markets. The increasing competition in European and international fruit markets is generating the need for improved ripeness evaluation techniques to assess fruit quality standards. As tropical fruits produce a wide range of volatile organic compounds (VOCs), PTR-ToF-MS was used to fingerprint the volatile profile of four tropical fruits (avocado, banana, mango and mangosteen) and determine whether this instrument could be used to assess fruit ripening stages, which was measured with traditional methods. Data were subsequently subjected to partial least squares discriminant analysis. By pooling the entire dataset together, it emerges that VOCs and chemical analyses enabled the separation of the two different ripening stages of all fruits, while skin color and fruit firmness did not always enable that separation. For avocado, banana and mangosteen, it was possible to observe the process of maturation during the shelf life, via physicochemical parameters and VOC analysis, whereas for mango, the constant production of methanol and acetaldehyde detected at both stages, together with the unchanged of evolution of the physicochemical parameters (TSS, pH and color), indicated a lack of maturation. Given the rapidity and the potential to use this analysis method on a large scale, the PTR-ToF-MS has a high potential to become a commercial standard tool for monitoring food quality from entering the storage chain up to the ‘ready to eat’ labeling.

Lab-on-Spoon – a 3-D integrated hand-held multi-sensor system for low-cost food quality, safety, and processing monitoring in assisted-living systems

Abstract. Distributed integrated sensory systems enjoy increasing impact leveraged by the surging advance of sensor, communication, and integration technology in, e.g., the Internet of Things, cyber-physical systems, Industry 4.0, and ambient intelligence/assisted-living applications. Smart kitchens and "white goods" in general have become an active field of R&D. The goal of our research is to provide assistance for unskilled or challenged consumers by efficient sensory feedback or context on ingredient quality and cooking step results, which explicitly includes decay and contamination detection. As one front end of such a culinary-assistance system, an integrated, multi-sensor, low-cost, autonomous, smart spoon device, denoted as Lab-on-Spoon (LoS), has been conceived. The first realized instance presented here features temperature, color, and impedance spectroscopy sensing in a 3-D-printed spoon package. Acquired LoS data are subject to sensor fusion and decision making on the host system. LoS was successfully applied to liquid ingredient recognition and quality assessment, including contamination detection, in several applications, e.g., for glycerol detection in wine. In future work, improvement to sensors, electronics, and algorithms will be pursued to achieve an even more robust, dependable and self-sufficient LoS system.

Android integrated urea biosensor for public health awareness

Integration of a biosensor with a wireless network on the Android 4.2.1 (Jelly Bean) platform has been demonstrated. The present study reports an android integrated user friendly Flow injection analysis-Enzyme thermistor (FIA-ET) urea biosensor system. This android-integrated biosensor system will facilitate enhanced consumer health and awareness alongside abridging the gap between the food testing laboratory and the concerned higher authorities. Data received from a flow injection mode urea biosensor has been exploited as an integration point among the analyst, the food consumer and the responsible higher authorities. Using the urea biosensor as an example, an alarm system has also been demonstrated both graphically and through text message on a mobile handset. The presented sensor integrated android system will also facilitate decision making support system in various fields of food quality monitoring and clinical analysis.