Food Samples Research Articles

Investigation of bisphenol S (BPS) in packaged fish, meat, cheese, and price labels on their corresponding packages

As an alternative to bisphenol A (BPA), bisphenol S (BPS) has been used as an ink developer in thermal paper products including price labels on food packaging which have been suggested as the sources of BPS found at high levels in packaged fish samples. BPS in the printed price labels glued onto the outside of plastic film could migrate indirectly from the printed surface through the paper, adhesive and film into the food. In order to investigate if price labels could also be the sources of BPS detected in the meat samples in our previous studies, meat and other food samples packaged under different conditions were collected, and BPS in these samples together with the price labels on the corresponding packaging were extracted with solvent followed by solid phase extraction and stable isotope dilution LC-MS/MS analysis. BPS was detected at very high levels (161.7–222.4 µg/cm2) in all the five sticker type of price labels, indicating BPS being the dominant if not the sole ink developer. BPS was also detected in all the 26 continuous roll type of price labels but at very low levels (0.017–18 ng/cm2), indicating that the dominant ink developer is likely one of the other alternatives, rather than BPS. Despite BPS being detected in all price labels on packaging of fish, meat, and cheese samples, BPS was not detected or detected in only a few fish, meat, and cheese samples at levels considerably lower than the current EU specific migration limit (SML) of 50 ng/g food for BPS authorised under Regulation (EU) 10/2011.

Rainbow-inspired multicolor lateral flow immunoassay using multibranched platinum–rhodium-cobalt nanoparticles

Traditional lateral flow immunoassay (LFIA) using single-color labels has limitations in indistinct color change and restriction to the single-mode readout, which can hardly meet the demands of high-performance detection. Inspired by the multiple colors of the rainbow, we outline a multicolor LFIA using multibranched trimetallic platinum–rhodium-cobalt nanoparticles (PRCNPs) as signal labels to initiate multicolor conversion for diverse and multicolor readouts. The intrinsic properties of PRCNPs including their trimetallic composition, multibranched morphology, and strong absorption in the visible spectrum, confer advantages in catalytic activity, antibody utilization, and signal readout. Through the synergistic integration of the catalytic PRCNPs with the etching of gold nanorods, PRCNPs-LFIA enables multicolor readouts in a rainbow-like manner. PRCNPs-LFIA allows for qualitative analysis of acetamiprid, a widely-used neonicotinoid insecticide, at 2 ng mL−1. It also provides semi-quantitative analysis based on the discrimination of at least 10 colors. Furthermore, quantitative analysis can be conducted across multiple color spaces within the range of 0.01-10 ng mL−1, achieving a lowest detection result of 0.006 ng mL−1. The recoveries of acetamiprid in food samples detected by PRCNPs-LFIA in grayscale and multiple color space modes are 87.35%-103.59%, 85.56%-114.33%, 86.14%-114.77%, and 87.81%-112.01%, respectively, with all coefficients of variation below 15%. These results demonstrate the feasibility and accuracy of PRCNPs-LFIA in practical applications. Overall, this study illustrates the potential of multifunctional PRCNPs in the development of multicolor LFIA and broadens the biosensing strategies for point-of-care testing.

Fabrication of Raman reporter molecule–embedded magnetic SERS tag for ultrasensitive immunochromatographic monitoring of Cd ions and clenbuterol in complex samples

A rapid, simple but sensitive analytical method for the simultaneous monitoring of heavy metal ions and illegal additives in complex samples remains lacking. We reported a difunctional capture–detection surface-enhanced Raman scattering (SERS) immunochromatographic assay (ICA) for the direct detection of the heavy metal residue Cd ion (Cd2+) and illegal additive clenbuterol (CLE) with high sensitivity and specificity herein. A novel magnetic SERS tag (Fe@RAu) with a Raman reporter molecule–embedded raspberry-like Au shell was fabricated via a one-step reduction reaction that not only simplified the fabrication of common magnetic SERS nanomaterials but also improved SERS activity to increase detection sensitivity. The difunctional SERS–ICA enabled the fast magnetic enrichment of the target small molecules in complex specimens and ultrasensitive and quantitative determination of CLE/Cd2+ on the two test lines of the ICA system. The limits of detection of the developed method for CLE and Cd2+ were as low as 0.48 and 1.88 pg/mL, respectively, and about 2000 and 500 times lower than those of conventional AuNP-based ICA strips. The excellent practicability of Fe@RAu–ICA for real food samples analysis was also demonstrated, revealing the potential of the proposed assay for rapid and on-site screening of small-molecule pollutants.

A novel electrocatalyst based on NiO@C-dot nanocomposites for sensitive determination of ophthalmic drugs

This study proposed a novel electrochemical sensor for the sensitive measurement of the eye medication ofloxacin (OFX), which is based on a NiO@C-dot nanocomposite. The NiO@C-dot nanocomposite was synthesized using the sol-gel method, which was then applied to alter a glassy carbon electrode (GCE). With regard to OFX, the modified GCE shown outstanding electrochemical activity along with good sensitivity, selectivity, and stability. With OFX concentrations ranging from 5 µM to 975 µM, the NiO@C-dot/GCE showed a linear relationship with a sensitivity of 0.63994 µA/µM. The limit of detection (LOD) was 0.023 µM. The response to 50 µM OFX was measured, and the electrode was stored at 4°C after each test in order to evaluate the sensor's long-term stability and repeatability. After 20 days, the peak current response was still 97.89 % of its initial value. After 40 days of prolonged storage, 93.78 % of the electrode's original responsiveness was retained. The sensor showed a recovery rate of 97.37–99.70 % in all sample types when it was used to detect OFX in human urine, tap water, and food samples. These findings highlight the NiO@C-dot/GCE's outstanding selectivity, dependability, and longevity as solid platforms for OFX detection in complicated samples for a range of applications.

An electrochemical biosensor for sensitive detection of live Salmonella in food via MXene amplified methylene blue signals and electrostatic immobilization of bacteriophages.

Anovel bacteriophage-targeted electrochemical biosensor designed for accurate and quantitative detection of live Salmonella in food samplesis presented. The biosensor is simply constructed by electrostatic immobilizing bacteriophages on MXene-nanostructured electrodes. MXene, renowned for its high surface area, biocompatibility, and conductivity, serves as an ideal platform for bacteriophage immobilization. This allows for a high-density immobilization of bacteriophage particles, achieving approximately 71 pcs μm-2. Remarkably, the bacteriophages immobilized MXene nanostructured electrodes still maintain their viability and functionality, ensuring their effectiveness in pathogen detection. Therefore, the proposed biosensor exhibited enhanced sensitivity with a low limit of detection (LOD) of 5CFUmL-1. Notably, the biosensor shows excellent specificity in the presence of other bacteria that commonly contaminate food and can distinguish live Salmonella from a mixed population. Furthermore, it is applicable in detecting live Salmonella in food samples, which highlights its potential in food safety monitoring. This biosensor offers simplicity, convenience, and suitability for resource-limited environments, making it a promising tool for on-site monitoring of foodborne pathogenic bacteria.

Microplasma-assisted construction of cross-linked network hierarchical structure of NiMoO4 nanorods @NiCo-LDH nanosheets for electrochemical sensing of non-enzymatic H2O2 in food

The accumulation of small doses of hydrogen peroxide (H2O2) into food can cause many diseases in the human body, and it is urgent to develop efficient detection methods of H2O2. Herein, the hierarchical structure composite of NiCo-LDH nanosheets crosslinked NiMoO4 nanorods was grown in situ on carbon cloth (NiMoO4 NRs@NiCo-LDH NSs/CC) by micro-plasma assisted hydrothermal method. Thanks to the synergistic effect of three metals and (NiMoO4 NRs@NiCo-LDH NSs/CC) provided by nanorods/nanosheets hierarchical structure, NiMoO4 NRs@NiCo-LDH NSs/CC exposes more active sites and achieves rapid electron transfer. The H2O2 electrochemical sensor was constructed as the working electrode with a linear range of 1 μmol L−1 to 9.0 mmol L−1 and detection limit of 112 nmol L−1. In addition, the sensor has been successfully applied to the detection of H2O2 in food samples, the recovery rate is 95.2%–106.62%, RSD < 4.89%.

An ultrasensitive electrochemical sensor based on NiFe-LDH-MXene and ruthenium nanoparticles composite for detection of nitrofurantoin in food samples

The excessive use of nitrofurantoin (NFT) represents a threat to ecosystems and food safety, making it necessary to develop efficient and accurate detection methods. Herein, the Ru/NiFe-LDH-MXene/SPCE electrode was successfully synthesized by one-step electrodeposition and employed to the NFT electrochemical sensing. Combining 2D MXenes with multifunctional 2D layered double hydroxides (LDHs) creates synergistic interactions within the MXene-LDH heterostructures, modifying the electrochemical performance. Furthermore, the incorporation of noble metal nanoparticles and nanoclusters can significantly enhance electrochemical performance by promoting favorable interactions at the metal-carrier interface and optimizing the rearrangement of electronic structure. Based on this, the developed Ru/NiFe-LDH-MXene/SPCE sensor demonstrates remarkable sensitivity (152.44 μA μM−1 cm−2) and an ultralow detection limit (2.2 nM). Notably, the sensor was employed for NFT detection in food samples with satisfactory recoveries, making it a promising electrochemical sensor for the detection of NFT.

Metallic silver-alloyed copper oxide electro-catalyst: A high-sensitivity platform for propoxur insecticide detection in food samples

BackgroundCarbamate insecticides find widespread use in crop protection. Propoxur (PPX) is a type of pesticide classified as a carbamate insecticide, commonly used to control pests in both agriculture and households. The chances of these compounds being present are quite high. For this reason, it is imperative to perform a quantitative analysis of food samples to assess insecticides. MethodsThe development of a sensitive sensor using plate-like metallic silver alloyed copper oxide (m-Ag-CuO) allowed for the detection of PPX in food samples. The physical characteristics of m-Ag-CuO were determined through the use of microscopic and spectroscopic techniques. With its high sensitivity and exceptional selectivity, the electrochemical sensing method provides rapid and accurate results, making it a preferred choice for detect PPX. Significant findingsThe fabricated sensor showed impressive performance under optimal experimental conditions, with a limit of detection (LOD), limit of quantification (LOQ) and a sensitivity are 0.62 ng/L and 1.9 ng/L, and 0.67 µA (ng/L)–1 cm–2. We assessed the functionality and suitability of the sensor through selective study and analysis of food samples, achieving a recovery rate of 95 – 102 %. This indicates that the sensor successfully adapted to analyze PPX in different food products.

Low-cost heat assisted ambient ionization source for mass spectrometry in food and pharmaceutical screening.

Ambient Ionization Mass Spectrometry (AI-MS) techniques have revolutionized analytical chemistry by enabling rapid analysis of samples under atmospheric conditions with minimal to no preparation. In this study, the optimization of a cold atmospheric plasma for the analysis of food and pharmaceutical samples, liquid and solid, using a Heat-Assisted Dielectric Barrier Discharge Ionization (HA-DBDI) source is described. A significant enhancement in analyte signals was observed when a heating element was introduced into the design, potentially allowing for greater sensitivity. Furthermore, the synergy between the inlet temperature of the mass spectrometer and the heating element allows for precise control over the analytical process, leading to improved detection sensitivity and selectivity. Incorporating computational fluid dynamic (CFD) simulations into the study elucidated how heating modifications can influence gas transport properties, thereby facilitating enhanced analyte detection and increased signal intensity. These findings advance the understanding of HA-DBDI technology and provide valuable insights for optimizing AI-MS methodologies for a wide range of applications in food and pharmaceutical analysis.

A versatile fluorescent probe for the ratiometric detection of hydrazine (N2H4) in water, soil, plant, and food samples

Hydrazine (N2H4) is a crucial chemical raw material extensively utilized in chemical production. However, due to its volatility, water solubility, and high toxicity, both the gaseous form and aqueous solution of N2H4 pose significant environmental risks by causing severe pollution that can adversely impact plants, microorganisms, and human health. Therefore, accurate detection of N2H4 in the environment is imperative for safeguarding public health. In this study, we synthesized a ratiometric fluorescent probe (BCaz-Cy2) based on Carbazole and Hemicyanine groups. This probe exhibits simple synthesis procedure, rapid response time, high sensitivity and selectivity as well as remarkable detection signals. It enables effective detection of N2H4 in various matrices such as water, food, soil and plant samples thereby significantly expanding the scope of applications for N2H4 probes.

Development of Zeolite Imidazole Framework-Based Adsorbent for Effective Microextraction and Preconcentration of Histamine in Food Samples.

This study is the first to focus on the preconcentration and determination of histamine (HIS) in food samples using zeolite imidazole frameworks (ZIFs) on a solid-phase microextraction (SPME) platform. ZIF was developed on a polypropylene hollow fiber (PPHF) substrate (ZIF@PPHF) and characterized. The extraction performance was optimized by adjusting several parameters, including pH, contact time for adsorption, and desorption conditions. Under the optimized conditions, a wide linear dynamic range (0.05-250 mg/L) with high R2 values (0.9989), low limit of detection (0.019 mg/L), and low limit of quantification (0.050 mg/L) were determined as analytical figures of merit. Additionally, a reusability study confirmed that ZIF@PPHF preconcentrated 83% of the HIS up to the fourth cycle. The developed method was used to preconcentrate HIS in fish and cheese samples. The spiked real samples confirmed the validity and accuracy of this method. The percentage mean recoveries ± relative standard deviation (% RSD, n = 3) at the concentration levels of 5, 10, and 50 mg/L of HIS and the sample amount of 5 g for intra- and inter days ranged from 97 ± 1.10 to 102.80 ± 0.90 and from 96.40 ± 1.82 to 103.40 ± 0.79, respectively. The results suggest that the analytical method validation parameters were acceptable, indicating the repeatability and sensitivity of the method.

Genetic Characterization, Antibiotic Resistance, and Virulence Genes Profiling of Bacillus cereus Strains from Various Foods in Japan.

Bacillus cereus sensu stricto is a foodborne pathogen that causes food poisoning. Their spore and biofilm-forming abilities persist in various environments and foods. This study investigated the prevalence, virulence, antibiotic resistance, and genetic diversity of B. cereus s. s. strains isolated from various food samples. Of 179 samples, 22.34% were positive for B. cereus s. s., with significantly high detection rates in milk products and raw chicken meat. Forty strains were isolated from positive samples. Matrix-assisted laser desorption ionization/time of flight mass spectrometry analysis revealed nine distinct clusters and multi-locus sequence typing revealed 34 sequence types including 23 novel sequences, demonstrating high genetic diversity among the isolates. PCR analysis revealed that all the strains contained at least one toxin gene, but none contained the cytK gene. Antibiotic resistance tests revealed that all isolates were classified as multidrug-resistant, with high resistance levels, particularly to β-lactam antibiotics and vancomycin, but were susceptible to gentamicin. All isolates showed variations in biofilm formation. This study highlights the significant public health risk due to B. cereus s. s. and underscores the need for stringent monitoring and control measures in food production to manage antimicrobial resistance and ensure food safety.

2D/1D VSe2/MWCNT hybrid-based electrochemical sensor for carbendazim quantification of environmental, food, and biological samples.

Forthe first time the sensitive determination of carbendatim (CRB) is reportedutilizing a well-designed sensing architecture based on vanadium diselenide-multiwalled carbon nanotube (VSMC). FTIR, XRD, FESEM, EDS, and EIS were employed to evaluate the sensor's structural integrity, and the results demonstrated the successful integration of nanomaterials, resulting in a robust and sensitive electrochemical sensor. Cyclic voltammetry (CV) and chronoamperometric (CA) investigations showed that the sensor best performed at pH 8.0 (BRB) with an excellent detection limit of 9.80nM with a wide linear range of 0.1 to 10.0µM. A more thermodynamically viable oxidation of CRB was observed at the VSMC/GCE, with a shift of 200mV in peak potential towards the less positive side compared with the unmodified GCE. In addition, the sensor demonstrated facile heterogeneous electron transfer, favorable anti-fouling traits in the presence of a wide range of interferents, good stability, and reproducible analytical performance. Finally, the developed sensor was validated for real-time quantification of CRB from spiked water, food, and bio-samples, which depicted acceptable recoveries (98.6 to 101.5%) with RSD values between 0.35 and 2.23%. Further, to derive the possible sensing mechanism, the valence orbitals projected density of states (PDOS) for C, H, and N atoms of an isolated CRB molecule, VSe2 + CNT and VSe2 + CNT + CRB were calculated using density functional theory (DFT) calculations. The dominant charge transfer from the valence 2p-orbitals of the C and N atoms of CRB to CNT is responsible for the electrochemical sensing of CRB molecules.

Detection Limits of Insect Fragments in Spiked Whole Wheat Flour Using Multiplex Polymerase Chain Reaction (PCR)

The need for a sensitive molecular method to detect specific species of insect contaminants in food products remains a significant challenge in the food industry. This study evaluated the detection limit of a multiplex end-point PCR assay for detecting insects in food. The assay amplifies two fragments of the cytochrome oxidase subunit I gene (COI-Fa and COI-Fb) and one fragment of the protein-coding wingless (wg) gene found in insects. Five insect species, comprising three vectors of foodborne pathogens (the housefly, Musca domestica, the American cockroach, Periplaneta americana, and the pharaoh ant, Monomorium pharaonis) and two storage insect pests (the red flour beetle, Tribolium castaneum and the Indian meal moth, Plodia interpunctella), were spiked separately and in combination at levels of 1, 0.1, 0.01, and 0.001% in whole wheat flour. At spike levels greater than 0.01%, amplicon bands of expected sizes were seen in 100% of samples containing fragments from distinct insect species. At least 25% of spiked samples at the lowest spike level had amplicon bands, except for samples spiked with M. domestica. Results showed an 18.9% probability (with 11.3% and 30% lower and upper confidence limits, respectively) of detecting insect fragments at the lowest spike level (0.001%, corresponding to 3–22 fragments), which is far below the FDA’s regulatory level of less than 75 fragments per 50 g of wheat flour. The intensity of amplicon bands in the gel images was higher at higher spike levels. However, this method is not quantitative enough to extrapolate the intensity of the amplicon bands to the number of insect fragments present in a sample. This multiplex assay was also evaluated in a variety of market food samples derived from plants and animals, showing its potential use in various food types. Overall, the sensitivity and specificity of this molecular approach suggest that it could be used in the future as a screening tool for detecting insect contaminants in food.

Core–satellite-structured magnetic nanozyme enables the ultrasensitive colorimetric detection of multiple drug residues on lateral flow immunoassay

BackgroundExcessive use of veterinary drugs causes severely environmental pollution and agricultural pollution, and poses great threat to human health. A simple method for the rapid, highly sensitive, and on-site monitoring of veterinary drug residues in complex samples remains lacking. ResultsIn this study, we propose a catalytically enhanced colorimetric lateral flow immunoassay (LFA) based on a novel core–satellite-structured magnetic nanozyme (Fe–Au@Pt) that can simultaneously and quantitatively detect three common veterinary drugs, namely, gentamicin (GM), streptomycin (STR), and clenbuterol (CLE), within a short testing time (<30 min). The Fe–Au@Pt nanozyme was simply prepared through the self-assembly of numerous Au@Pt nanoparticles on a large Fe3O4 core via electrostatic adhesion, which exhibited the advantages of high peroxidase-like activity, strong magnetic responsiveness, and multiple catalytic sites. Under the dual-signal amplification effect of magnetic enrichment and catalytic enhancement, the proposed nanozyme-LFA allowed the multiplex detection of STR, CLE, and GM with detection limits of 10.1, 6.3, and 1.1 pg/mL, respectively. SignificanceThe developed Fe–Au@Pt–LFA achieves direct, simultaneous, and accurate detection of three target drugs in food samples (honey, milk, and pork). The proposed assay shows great potential for application in the real-time monitoring of small-molecule pollutants in complex environment.

Dispersive liquid–liquid microextraction based on solidification of floating organic droplet and spectrophotometric determination of Allura red using green deep eutectic solvent as disperser solvent: Green profile assessment

In this study, dispersive liquid–liquid microextraction based on the solidification of a floating organic drop (DLLME-SFO) was investigated for allura red (AR) preconcentration from water and food samples using green deep eutectic solvent (DES) as a disperser solvent. Compared to the conventional disperser solvents, the DES, which consists of choline chloride and citric acid (1:1), exhibited a higher AR recovery with simple preparation, being eco-friendly and low expense. The proposed protocol showed relatively high recovery values of AR in real samples (97.0–99.5 %). The optimum conditions for AR extraction were pH=3.0, 250.0 µl DES volume, CTAB (4.0 × 10−4 mol L−1), KCl (0.10 mol L−1), 100 µl of 1-dodecanol, and centrifugation: 4.0 min. at 4000 rpm. The validated method showed linearity from 100 to 5000 µg L−1 with 14.4 enrichment factor for 10.0 mL sample. The limit of detection was 29.9 µg L−1 and the relative standard deviation was 3.7 % for five replicate analysis of 300.0 µg L−1. The AR content in studied food samples was determined by spectrophotometry and high-performance liquid chromatography (HPLC). Our proposed method is simple and fast, as the whole process for AR extraction requires only 9.0 min. The analytical eco-scale AGREEnness calculator (AGREE), the blue applicability grade index (BAGI), and the ChlorTox scale were evaluated.

Reduced graphene oxide decorated NiCo2(OH)6 nanoflowers for vortexed assisted dispersive µ-solid-phase extraction of organophosphorus pesticides in baby food cereal, rice and wheat flour

Food safety is an important issue to protect humane health and improve the life quality. Hence, analysis of the possible contaminants in food samples is essential. A rapid and efficient vortexed-assisted dispersive µ-solid-phase extraction coupled with gas chromatography-mass spectrometry was proposed for simultaneous separation/preconcentration and determination of five commonly used organophosphorus pesticides. Reduced graphene oxide decorated NiCo2(OH)6 nanoflowers as a novel nanostructure was synthetized and introduced for separation of the target pesticides from the wheat flour, rice flour, and baby food cereal samples. The characterization of the nanoflowers was accomplished by SEM-EDX, XRD, and FT-IR techniques. The main factors including pH, the amount of nanoflower, the volume of sample solution, salt concentration (ionic strength), desorption conditions (i.e. desorption solvent type and volume, and desorption time) on the pesticides extraction efficiencies were inquired using matrixed match method. Applying the optimum conditions, the linearity of 0.100–500.000 µg kg−1, LODs and LOQs in the range of 0.03–0.04 µg kg−1 and 0.1 µg kg−1 for the studied food samples were obtained. The repeatability (intra–day precision (n = 5)) of ≤ 2.0 % and reproducibility (inter–day precision, days = 5, n = 3) of ≤3.1 % and were appraise at three concentration levels (10, 50 and 100 μg kg−1 of each analyte). High relative recoveries of 90.0–99.3 % ascertained high potential of the presented method for complex matrix analysis.

Fluorescence array sensor based on lanthanide complex for pattern recognition detection of fluoroquinolone antibiotics

Fluoroquinolone antibiotics, a class of animal and human useful antibiotics, are widely utilized in numerous fields including biomedical science, animal husbandry, and aquatic finfish farming. Its high demand and wide application have directly or indirectly led to substantial consumption and discharge of antibiotics, affecting not only the environment but also endangering human health through bioaccumulation. Hence, rapid and precise detection of trace antibiotics in water, food, and biological samples is critically important. This research synthesized Tb3+/Eu3+ complexes with dual emission centers, and a fluorescence sensor array was constructed with the fluorescence intensity ratio F1/F2 of the two emission centers as a signal. Different sensitization effect of fluoroquinolone antibiotics towards lanthanide complexes aided in differentiating five fluoroquinolone antibiotics from two others. Additionally, the sensor array can effectively detect fluoroquinolone antibiotics in real samples, suggesting its reliability and practicality of complex sample analysis. The excellent qualitative and quantitative analysis ability of this strategy for fluoroquinolone antibiotics offers a novel perspective for antibiotic residue detection, showcasing a new opportunity for lanthanide complex application in sensor arrays.

A novel electrochemical sensor (Au-Ag-ANCCs/r-GO/poly(L-histidine)/GCE) for the simultaneous determination of vancomycin and ceftriaxone residues in chicken meat, fish, and milk samples

The widespread use of antibiotics in humans and animals has resulted in the accumulation of their residues in food and the environment, posing significant threats to human health, the environment, and the global economy. Herein, we have developed a highly sensitive and selective electrochemical sensor by integrating gold-silver alloy nanocoral clusters (Au-Ag-ANCCs) with reduced graphene oxide (r-GO) and poly(L-histidine) composites at the surface of glassy carbon electrode (GCE). The developed sensor (Au-Ag-ANCCs/r-GO/poly(L-histidine)/GCE) was designed for the simultaneous determination of vancomycin (VAN) and ceftriaxone (CFT) residues in food samples. Its morphological and electrochemical properties were exhaustively examined using UV–Vis spectroscopy, FT-IR, XRD, SEM, EDX, EIS, and CV. The sensor showed exceptional performance in a linear range of 1.0 pM to 120 μM for VAN and 1.0 pM to 290 μM for CFT. The limits of detection were 0.11 pM for VAN and 0.017 pM for CFT, while the limits of quantification were 0.36 pM for VAN and 0.057 pM for CFT. The sensor exhibited remarkable reproducibility, repeatability, stability, and selectivity. It was successfully applied to detect VAN and CFT residues in chicken meat, fish, and milk, achieving recoveries of 96.2–102.1 % with relative standard deviation (RSD) below 5 %. Therefore, the sensor is an ideal tool for addressing the global antibiotic residue crisis in food samples.

Phage-induced “one-to-many” FRET sensor for highly sensitive detection of Escherichia coli O157:H7

As a foodborne pathogen capable of causing severe illnesses, early detection of Escherichia coli O157:H7 (E. coli O157:H7) is crucial for ensuring food safety. While Förster resonance energy transfer (FRET) is an efficient and precise detection technique, there remains a need for amplification strategies to detect low concentrations of E. coli O157:H7. In this study, we presented a phage (M13)-induced “one to many” FRET platform for sensitively detecting E. coli O157:H7. The aptamers, which specifically recognize E. coli O157:H7 were attached to magnetic beads as capture probes for separating E. coli O157:H7 from food samples. The peptide O157S, which specifically targets E. coli O157:H7, and streptavidin binding peptide (SBP), which binds to streptavidin (SA), were displayed on the P3 and P8 proteins of M13, respectively, to construct the O157S-M13K07-SBP phage as a detection probe for signal output. Due to the precise distance (≈3.2 nm) between two neighboring N-terminus of P8 protein, the SA-labeled FRET donor and acceptor can be fixed at the Förster distance on the surface of O157S-M13K07-SBP via the binding of SA and SBP, inducing FRET. Moreover, the P8 protein, with ≈2700 copies, enabled multiple FRET (≈605) occurrences, amplifying FRET in each E. coli O157:H7 recognition event. The O157S-M13K07-SBP-based FRET sensor can detect E. coli O157:H7 at concentration as low as 6 CFU/mL and demonstrates excellent performance in terms of selectivity, detection time (≈3 h), accuracy, precision, practical application, and storage stability. In summary, we have developed a powerful tool for detecting various targets in food safety, environmental monitoring, and medical diagnosis.