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Classification of foodborne bacteria using hyperspectral microscope imaging technology coupled with convolutional neural networksa??
摘要： Foodborne pathogens have become ongoing threats in the food industry, whereas their rapid detection and classification at an early stage are still challenging. To address early and rapid detection, hyperspectral microscope imaging (HMI) technology combined with convolutional neural networks (CNN) was proposed to classify foodborne bacterial species at the cellular level. HMI technology can simultaneously obtain both spatial and spectral information of different live bacterial cells, while two CNN frameworks, U-Net and one-dimensional CNN (1D-CNN), were employed to accelerate the data analysis process. U-Net was used for automating cellular regions of interest (ROI) segmentation, which generated accurate cell-ROI masks in a shorter timeframe than the conventional Otsu or Watershed methods. The 1D-CNN was employed for classifying the spectral profiles extracted from cell-ROI and resulted in a higher accuracy (90%) than k-nearest neighbor (81%) and support vector machine (81%). Overall, the CNN-assisted HMI technology showed potential for foodborne bacteria detection.
关键词： Convolutional neural network,Machine learning,Hyperspectral microscopy,Food safety,Foodborne pathogen,Rapid classification
更新于2025-09-23 15:19:57
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Immunochromatographic assay for melamine based on luminescent quantum dot beads as signaling probes
摘要： To screen and detect the harmful substance melamine (MEL), a quantum-dot-bead-based immunochromatographic assay (QB-ICA) was formulated. After optimization, calibration was performed within the linear range from 0.06 to 0.28 ng mL?1, with limit of detection (LOD) of 0.04 ng mL?1. The LOD was 35 times lower than that of ICA that used colloidal gold nanoparticles (LOD ? 1.4 ng mL?1) and 40 times lower than that of the assay based on quantum dots (LOD ? 1.6 ng mL?1). In the detection of MEL in spiked pure milk using the proposed QB-ICA strategy, the LOD (LOD ? 0.19 ng mL?1) of the samples with the proposed pretreatment was 18.4 times lower than those of the samples without pretreatment (LOD ? 3.5 ng mL?1). The performance and practicability of the proposed QB-ICA system was validated; the obtained results reveal that QB-ICA is comparable with the conventional enzyme-linked immunosorbent assay (ELISA) method, but with enhanced applicability. Given its high sensitivity and practicability, the QB-ICA strategy could become a worthwhile alternative for the rapid, sensitive, and quantitative onsite detection of harmful substances, facilitating food safety monitoring.
关键词： melamine,quantum-dot-bead-based immunochromatographic assay,sensitivity,rapid detection,food safety
更新于2025-09-23 15:19:57
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A stable nanoscaled Zr-MOF for the detection of toxic mycotoxin through a pH-modulated ratiometric luminescent switch
摘要： A stable nanoscaled single-excitation ratiometric luminescent pH sensor (MPDB-PCN) over a broad pH range from 2.5 to 8.6 is fabricated through post-synthetic modification of PCN-224 with naphthalimide-derived molecules. Due to the rapid, sensitive and linear response to pH, MPDB-PCN is capable of detecting 3-nitropropionic acid (3-NPA), an acid neurotoxin in food safety, with a low detection limit of 15 μM in sugarcane juice.
关键词： Luminescent metal-organic frameworks,food safety,pH sensor,3-nitropropionic acid
更新于2025-09-19 17:13:59
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Fluorometric lateral flow immunoassay for simultaneous determination of three mycotoxins (aflatoxin B1, zearalenone and deoxynivalenol) using quantum dot microbeads
摘要： A fluorometric lateral flow immunoassay (LFA) is described for the simultaneous determination of the mycotoxins aflatoxin B1 (AFB1), zearalenone (ZEN) and deoxynivalenol (DON). The method is based on the use of CdSe/SiO2 quantum dot microbeads (QBs) with a mean diameter of 106 nm. These have strong red luminescence (with excitation/emission peaks at 365/622 nm) which results in enhanced sensitivity. The QBs binding with monoclonal antibodies (mAbs) as the signal probes can react specifically with AFB1, ZEN and DON, respectively. There is an inverse correlation between the fluorescence signal intensity of test line and the analyte content, which can realize the quantitative analysis of analytes within 15 min. The limits of detection in solution are 10, 80 and 500 pg mL?1 for AFB1, ZEN and DON, respectively. Besides, the average recoveries from spiked feed range from 85.5 to 119.0%, and the relative standard deviations are less than 16.4% for both intra- and inter-day assays. The method was used to analyze naturally contaminated feedstuff, and this resulted in a good agreement with data obtained by LC-MS/MS.
关键词： Rapid detection,LC-MS/MS,Food safety,Multiplexed,Immunochromatographic strip,Quantitative analysis,Cereal samples,Antibody,Feedstuff
更新于2025-09-12 10:27:22
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Fluorometric determination of aflatoxin B1 using a labeled aptamer and gold nanoparticles modified with a complementary sequence acting as a quencher
摘要： A fluorometric aptamer based assay is described for rapid and sensitive detection of aflatoxin B1 (AFB1). It is making use of a fluorescein (FAM) labeled anti-AFB1 aptamer and complementary DNA-modified gold nanoparticles (GNPs). In the absence of AFB1, the FAM-labeled aptamers hybridize with complementary DNA strands that were covalently immobilized on GNPs. This results in quenching of the green fluorescence (with excitation/emission peaks at 485/525 nm). In the presence of AFB1, the aptamer probe binds AFB1 and is released from the GNPs. Hence, fluorescence is restored. Under optimized conditions, AFB1 in the concentration range from 61 pM to 4.0 μM can be detected, and the detection limit is 61 pM. This assay is highly selective for AFB1. It was applied to the determination of AFB1 spiked into 50-fold diluted wine and 20-fold diluted beer.
关键词： Mycotoxin,Food safety,Environmental analysis,Fluorescence quenching,Fluorophore,Fluorescent probe,Nanomaterials,Nanoprobe
更新于2025-09-11 14:15:04
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Anion exchange polymeric sorbent coupled to high‐performance liquid chromatography with <scp>UV</scp> diode array detection for the determination of ten <i>N</i> ‐nitrosamines in meat products: a validated approach
摘要： Among mechanisms and molecules presumably involved in the carcinogenicity induced by meat consumption, the N-nitrosamines (N-NAs) are a class of compounds characteristic of processed meats. In this work, an analytical method for the determination of 10 N-Nitrosamines (N-Nitrosomorpholine, N-Nitriosomethyethylamine, N-Nitrosopyrrolidine, N-Nitrosodiethylamine, N-Nitrosopiperidine, N-Nitrosodipropylamine, N-Nitrosomethylaniline, N-Nitrosodibutylamine, N-Nitrosodiphenylamine, N-Nitrosodibenzylamine) in fresh meats and meat products was developed, optimized and validated. The method is based on optimized sample purification by solid phase extraction (anion exchange polymeric sorbent) and separation/detection by high performance liquid chromatography coupled to UV diode array detection. The validation procedure allowed to ascertaining good analytical performances in terms of sensitivity, selectivity towards interfering compounds, accuracy and robustness. The values obtained for precision (range: 4.3% - 14.4%) and recovery percentages (range: 80.8% - 95.1%) were compared to reference values indicated in the Decision No. 657/2002/EC, resulting as compliant. The measurement uncertainty (lower than 14.6%) was satisfactory for each N-NA as well.
关键词： meat,food safety,solid phase extraction,validation,diode array detection,Nitrosamines,processed meats,HPLC,carcinogenic compounds,anion exchange sorbent
更新于2025-09-11 14:15:04
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Detection of Salmonella from chicken rinsate with visible/near-infrared hyperspectral microscope imaging compared against RT-PCR
摘要： Salmonella is an organism of importance to the poultry industry with increasingly stringent government regulatory standards. Real-time polymerase chain reaction (RT-PCR) and plating procedures on nutrient enriched growth media have been the standard detection methods of Salmonella from broiler chicken carcasses for years. These methods are proven, but offer disadvantages in the amount of time or reoccurring sample cost. Here, we propose the use of a hyperspectral microscope imaging system (HMI) for comparison to standard detection methods. Broiler chicken carcasses were rinsed and plated on Salmonella selective agar. Colonies from plates were picked and RT-PCR was used as a confirmation test to verify plating results, while HMI was collected from the same colonies. Spectral signatures of cells were extracted between 450 – 800 nm from HMI collected with 100x objective. A quadratic discriminant analysis (QDA) was used to classify cells as either Salmonella positive or negative (n = 341). Spectra preprocessing minimized the influence of cellular shape on the spectra, increasing the initial classification accuracy of 81.8% to 98.5%, yielding a sensitivity of 1.0, and a specificity of 0.963. Results showed the potential as an initial investigation of HMI as a microbial confirmation tool, compared to RT-PCR.
关键词： Polymerase chain reaction,Salmonella,Food Safety,Hyperspectral microscope,Rapid detection
更新于2025-09-10 09:29:36
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Impedimetric sensor for tyramine based on gold nanoparticle doped-poly(8-anilino-1-naphthalene sulphonic acid) modified gold electrodes
摘要： A novel impedimetric sensor for the determination of tyramine (Tyr), a biogenic amine, on the surface of gold nanoparticle-poly-(8-anilino-1-napthalene sulphonic acid), AuNP-PANSA modified gold electrode (AuE) is presented for the first time. The AuNP were successfully synthesized by a green synthesis method. Their characterization and optimization were conducted using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, electrochemical impedance spectroscopy and cyclic voltammetry. Under optimal conditions, the impedimetric sensor revealed a relatively broad linear range from 0.8 to 80 μM similar to more complex architectures found in the literature and the limit of detection of 0.04 μM was the lowest achieved until now. In order to test the reliability of the proposed method, real sample application studies were conducted using dairy products and fermented drinks. It was found that the sensor presented a good selectivity and recovery. Furthermore, the impedimetric sensor shows good reproducibility, stability, selectivity and very small interferences which augur well for its application in food safety control processes.
关键词： electrochemical impedance detection,food safety control,impedimetric sensor,biogenic amine,tyramine
更新于2025-09-09 09:28:46
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Biosensors in Applications
摘要： These days, especially, the attention is increasing in high technology of sensors designed for various uses in biological matter, biomedicine, drug improvement, security, nutrition safety and ecological monitoring and measuring. The system of these sensors should typically be handy and economical, on condition that quick response with reliability, high sensitivity, and negligible false-reading counts are provided. Biosensors have a multi-disciplinary nature including: biology, chemistry, physics, instrumentation, electronics, optics, and market. The biosensors are detecting devices that combine a transducer with biologically sensitive and selective components. Biosensors can quantity combinations existing in the environment, chemical procedures, food and human body at inexpensive charge in comparison with traditional techniques. This editorial article briefly focuses on an overview of Biosensors, examples and providing a new vista of developments and applications.
关键词： biomedicine,environmental monitoring,Biosensors,food safety,applications
更新于2025-09-04 15:30:14