To develop a meat component detection method based on handheld quantitative real-time polymerase chain reaction (PCR) for rapid on-site identification of meat sources.

This study focused on the pork, chicken and duck-derived components, explored the influence of the single factors of meat sample pretreatment tools, lysate composition, lysate concentration and lysate addition amount on the extracted DNA, and constructed a rapid pretreatment method for meat samples; screened specific primers and probes, used the handheld quantitative teal-time PCR instrument to verify specificity, sensitivity and limit of detection, and drew amplification standard curves; and detected the real single and mixed meat samples.

The established rapid pretreatment method for meat samples could be completed within 5 min, the DNA extraction took 10 min, and the extracted DNA could meet the requirements of subsequent experiments. The detection methods exhibited high specificity for pork,chicken and duck samples. The limits of detection of pork, chicken and duck-derived DNA components were 0.010,0.001 and 0.001 ng/µL. The standard curve showed a sound linear relationship. The amplification standard curve of pig DNA was: Y=–3.956X+38.803, r²=0.9956. The amplification standard curve of chicken DNA was: Y=–3.499X+40.491,r²=0.9909. The amplification standard curve of duck DNA was: Y=–3.961X+39.192, r²=0.9962. The method was successfully applied to detect 28 meat samples with a 100% success rate.

These results indicate that the rapid meat sample pretreatment method established in this experiment can be used for the rapid and accurate detection of pork, chicken and duck meat on a handheld quantitative real-time PCR all-in-one machine. This approach provides robust technical support for monitoring and controlling meat adulteration at the retail or market level.

To establish a method for rapid detection of iron content in tap water and food samples by paper-based microfluidic chip.

The paper-based chips were cut out using an embossing gadget. And the paper chip was prepared by soaking. Samples to be tested could be dropped onto the prepared chips directly. When the chip showed a stable color based on O-dinitrogen colorimetric method, the chip could be placed on a self-made platform for taking photo. Then the gray value of the picture could be read and the iron concentration could be acquired. The study selected the type of filter paper, and optimized the concentrations of 1,10-phenanthroline and hydroxylamine hydrochloride during soaking, as well as the soaking time and coloring time.

Whatman 3#filter paper was selected to prepare the paper chip. And the cut paper chip was soaked in acetate buffer solution containing 8.00 g/L of 1,10-phenoroline and 50.00 g/L of hydroxylamine hydrochloride (pH=4.50) for 3 minutes.After the sample was dropped onto the paper chip for 15 minutes, photos could be taken for detection. When the concentration of Fe³⁺ in sample solution was 5.00×10^–3 mmol/L to 7.00 mmol/L, it had a good linear relationship between the gray value and the concentration. The limit of detection the paper chip method was 0.004 mmol/L. When the 13 kinds of interfering metal ions, including 1 mg/L Cd²⁺, Cu²⁺ and the like, were coexisting in the sample solution, they did not affect the detection of Fe³⁺. The adding standard recoveries were 86.0% to 114.7%. The relative standard deviations of the same sample 6 test results within the same day were 1.7% to 7.5%. And the relative standard deviations of 6 consecutive days detection results were 3.4% to 7.9%. The prepared paper chip could be stored for at least for 3 months under the condition of avoiding light at 4 ℃. When the actual samples were detected,the relative deviation between the paper chip method and the flame atomic absorption method was less than or equal to 2.404%.

The iron detection method based on paper-based chips established in this research is simple to operate, accurate and reliable, which can be a strong support for on-site rapid detection of iron content in food detection field.

To establish a method for the rapid determination of the content of 9 kinds of aconitum alkaloids in homemade Radix aconiti Kusnezoffii medicinal wine by ultra performance liquid chromatography-tandem mass spectrometry.

The wild Radix aconiti Kusnezoffii in Yunnan was used as the main raw material. It was made into 5 kinds of different shapes (whole, peeled, flake, block, powder), and 250 g was soaked in 900 mL of 52-degree corn to brew liquor, and the soaking time was about 1.5 years. Took 1 mL sample of medicinal liquor, added 30% methanol water solution (3:7, V:V) to 100 mL, and filtered it with 0.22 μm filter membrane, ready for testing. C₁₈ column and mobile phase of acetonitrile-0.1% formic acid water were used for gradient elution separation, multi-reaction monitoring mode detection, and quantification was carried out by matrix working curve external standard method.

The linear relationship of 9 kinds of aconitum alkaloids was good in the range of 1–100 μg/L, the correlation coefficients were all greater than 0.999, the limits of detection were 0.63–0.98 μg/L, the limit of quantitation were 2.11–3.26 μg/L, and the recovery rates were 81.14%–116.01% at low,medium and high concentrations, the relative standard deviations were 0.97%–11.26% (n=6). According to the analysis of actual samples, the content of diester alkaloids of 9 kinds of aconitum alkaloids in medicinal liquor was high, among which aconitine had the most content and strong toxicity.

This method is simple in pretreatment, high in sensitivity, good in accuracy and high in detection efficiency. It is suitable for rapid screening of 9 kinds of aconitum alkaloids in Radix aconiti Kusnezoffii homemade medicinal liquor in health emergency poisoning events, and provides strong technical support for rapid diagnosis of medical treatment and corresponding emergency treatment measures.

To establish a method for the rapid determination of malathion drug residues in Lonicera japonica by colloidal gold immunochromatography.

The residual malathion in honeysuckle can bind to the colloidal gold-labeled monoclonal antibody, inhibiting the binding of the antibody to the antigen on the nitrocellulose membrane (T line) and resulting in a color change on the T line, this study analyzed the effects of various factors, such as pH, antibody addition amount, antigen coating amount, type of freeze-drying protective agent, and Tween 20 addition amount on the test results.

The optimal conditions determined were as follows: The optimal pH for preparing the malathion monoclonal antibody (mAb) and goat anti-mouse immunoglobulin (lgG) gold-labeled antibody was 9.0; the optimal amount of Tween 20 added was 50 μL; and the optimal lyophilization protectant for the gold-labeled antibody was a mixture of 1.0 g sucrose, 0.5 g bovine serum albumin and 0.5 g mannitol. The optimized method achieved a limit of detection was 50 μg/kg for malathion in Lonicera japonica. Furthermore, the method exhibited high specificity for malathion; no cross-reactivity was observed with isocarbophos, profenofos, phoxim or fenthion at concentrations ranging from 200 to 1000 μg/kg.Method validation using negative and positive samples showed a false-positive rate of 1% and a false-negative rate of 0.5%, achieving consistency with the results from existing standard methods. The test strips produced based on this method could be stored for one year at room temperature under sealed and dry conditions.

The method established in this study is simple to operate, highly specific, sensitive and accurate. It requires a short detection time and demonstrates good stability, making it suitable for the rapid screening of malathion residues in large batches of Lonicera japonica samples.

To establish an analytical method for the rapid detection of matrine pesticide residues in Fragaria ananassa Duch by colloidal gold immunochromatography.

By optimizing the labeling parameters of gold nanoparticles and the concentration of the test strip detection line, colloidal gold could bind with monoclonal antibodies against matrine under optimal conditions. By utilizing highly specific recognition of antibodies and antigens and visualization of gold labeled antibodies, the localization detection of matrine pesticide residues in Fragaria ananassa Duch could be achieved.

Determine the labeling parameters as follows: 1 mL of colloidal gold solution with 20 μL of 0.1 mol/L K₂CO₃, 8 μg of antibody, 5% polyvinyl pyrrolidone (PVP) surfactant,and an antigen transmembrane concentration of 0.10 mg/mL; using the above conditions, the limit of detection of matrine in Fragaria ananassa Duch samples was set to 10 μg/kg, and rapid detection was performed on 126 collected Fragaria ananassa Duch samples.

This method has high sensitivity and specificity, and can quickly and accurately detect residual matrine in samples, enabling rapid screening of a large number of samples on site.

To analyze the effects of different termination methods on the yield of theaflavins.

Theaflavins were prepared through the enzymatic action of potato polyphenol oxidase (PPO). A high performance liquid chromatography (HPLC) analysis was conducted to detect theaflavin compounds. The effects of 6 kinds of different termination methods on theaflavin yield were then analyzed.

Following treatment with microwave medium power, microwave high power, a 100 °C water bath and 3 kinds of inhibitors, the concentration of theaflavins was measured. The results of the HPLC analysis indicated that the 100 °C water bath treatment resulted in the highest theaflavin content, with theaflavin-3,3’-gallate (TFDG) reaching 32.47 µg/mL and theaflavin substances at 119.12 µg/mL.

The concentration of theaflavins is highest after treatment in a 100 °C water bath.The research findings may provide valuable reference for rapid detection and industrial-scale production of theaflavins.

To realize the rapid detection of toxin-producing Aspergillus carbonarius, and to establish a dual fluorescence quantitative polymerase chain reaction (qPCR) method for detecting the polyketide synthases(PKS) gene and nonribosomal peptide synthetase (NRPS) gene of Aspergillus carbonarius.

Taking the relatively conserved gene fragments of PKS and NRPS from toxin-producing Aspergillus carbonarius as targets,specific primer-probe sets were designed and screened respectively. After optimizing the reaction conditions of dual qPCR, the standard curve of the assay was established. Subsequently, the specificity, sensitivity, and repeatability of this method were verified. Finally, this method was used to test 80 actual samples and corn, peanut and soybean samples artificially inoculated with different concentrations of toxin-producing Aspergillus carbonarius spores.

The specificity test results demonstrated that this dual qPCR assay exhibited no non-specific amplification with common toxin-producing fungi such as Aspergillus flavus and Aspergillus parasiticus, but specifically amplified the PKS and NRPS genes of toxin-producing Aspergillus carbonarius. The sensitivity assay showed that the limit of detection of this method could reach 1×10² copies/μL. And the method presented excellent repeatability, with the intra- and inter-batch coefficients of variation both less than 1%. In the simulated sample test, this dual qPCR could detect spores at a minimum concentration of 1×10³ spores/mL in all 3 kinds of artificially infected samples.

The established dual fluorescence quantitative PCR has high sensitivity and accuracy, it can provide technical support for the early monitoring and control of ochratoxin A-toxin-producing Aspergillus carbonarius.

To prepare the Fe₃O₄@SA nanozyme gel microspheres with peroxide-like activity to construct a colorimetric sensor to detect the peroxide value (POV) of vegetable edible oils.

The standard curve of POVs of different types of vegetable edible oils was established by collecting the absorbance and the red,green, blue (RGB) information of the solution after color reaction with the microplate reader and smartphone, and the accuracy and practicability of the detection method were evaluated.

The POVs of 5 kinds of vegetable edible oils showed a good linear relationship in the range of 0–0.40 g/100 g. Compared with the results of the national standard method, the determination coefficient (R²) of the microplate reader colorimetric method and the smartphone digital image colorimetric method were both greater than 0.9500, and the root mean square error (RMSE) was less than 0.1.

The colorimetric detection system established based on the activity of Fe₃O₄@SA nanozyme gel microspheres has good accuracy and practicability, and the research results will provide a new idea for the analysis and detection of food safety factors.

To investigate process factors affecting the stability of rapid testing methods for mycotoxins in Triticum aestivum L. and Zea mays L..

To used Triticum aestivum L. and Zea mays L. as primary grain samples, a systematic evaluation was conducted on: Screening rates (99%, 97%, 95%, 93%, 91%)mixing methods (manual, mechanical single/double mixing), sample sizes (300, 400, 500, 600, 700 g), and 3 kinds of commercially available rapid testers (SinoTech, FlyingTest, Charm) on detection results for aflatoxin B₁, zearalenone and deoxynivalenol.

Toxin detection levels in raw grain correlated positively with sieving rate, reached a maximum of 667.61 μg/kg. However, variation among the 3 kinds of toxins differed significantly, likely due to their distinct distribution characteristics. Mechanical bidirectional mixed ensured thorough toxin dispersion, reduced detection error to 8.1%. Increasing sample mass enhanced result stability but complicated mixing procedures. Furthermore, all 3 kinds of rapid testing instruments (SinoTech, FlyingTest and Charm) exhibited measurement errors during toxin detection,potentially attributable to operational procedures and system calibration.

Optimising sample handling protocols effectively enhances the accuracy of rapid mycotoxin detection in grain, providing a theoretical basis for ensuring food safety and testing efficiency.

To investigate and study the pesticide residue situation of fresh fruits and vegetables in Xining City from 2024 to 2025.

This study employed the enzyme inhibition method to conduct rapid detection and analysis of organophosphorus and carbamate pesticide residues in samples from a fresh agricultural product trading market and production sources in Xining City, involving 185 fresh vegetables and 125 fresh fruits.Specifically, 13464 batches of fresh vegetables and 5712 batches of fresh fruits, totaling 310 varieties and 19176 batches of samples were tested.

There were 30 vegetable varieties and 7 fruit varieties, and 60 batches of samples had been tested for pesticide residues exceeding the standard. Among them, the top 5 fruits and vegetables with the highest over-standard rates were cucumbers, stem lettuce, fragrant asparagus, drought-tolerant melon and eggplant. The inhibition rates of the samples with pesticide residues exceeding the standard ranged from 51.30% to 99.89%. The overall qualitative preliminary screening positive rate was 0.33%, and the pass rates were between 98.92%–99.94%. The overall sample pass rate was 99.67%, which was relatively high.

The pesticide residue situation of fresh fruits and vegetables in Xining City from 2024 to 2025 is at a relatively safe level, but there are still cases of pesticide residues exceeding the standard. It is recommended to strengthen detection continuously and monitoring to ensure food safety for citizens further.

To prepare quality control samples of Listeria monocytogenes.

Listeria monocytogenes in the stationary phase was selected based on the growth curve. Then single-factor experiments and response surface methodology were used to optimize the lyoprotectant formulation. The prepared quality control samples were evaluated by homogeneity and stability.

Listeria monocytogenes cultured for 12 hours(stationary phase) was selected for freeze-drying. The optimized lyoprotectant formulation consisted of 13% skim milk powder, 8% trehalose and 3% sodium glutamate, achieving a bacterial survival rate of 82.27%. In the homogeneity test, the F-value was 2.747, which was lower than the critical F-value [F_0.05(9,10)=3.02]. In simulated stability tests, the quality control samples remained stable under transportation conditions which was 25 ℃ and 37 ℃for 7 days and storage conditions which was 4 ℃ and –20 ℃ for 28 days. The stability of the quality control samples was good.

The prepared Listeria monocytogenes control strain can be used as a quality control sample in laboratories.

To elucidate the differences in molecular epidemiological characteristics, antibiotic resistance and virulence properties of methicillin-resistant Staphylococcus aureus (MRSA) ST59 and ST398 in retail pork in the Hanzhong, and assess their potential public health risks.

Whole-genome sequencing was used to perform multilocus sequence typing (MLST), staphylococcal protein A gene (spa) typing, and staphylococcal cassette chromosome mec (SCCmec) typing for the isolates, and their resistance and virulence gene profiles were predicted. Antimicrobial susceptibility testing was conducted using the broth microdilution method; sheep red blood cell hemolysis test was used to evaluate hemolytic activity, and microplate crystal violet staining was employed to assess biofilm-forming ability.

Among the 43 MRSA isolates, ST59 (51.16%, 22/43) and ST398 (46.51%,20/43) were the dominant types. ST59 strains showed high homogeneity in molecular typing, mainly clustering in spa t437 (81.82%) and SCCmec IVa(2B) (90.91%); in contrast, ST398 strains exhibited high genetic diversity with various spa types and SCCmec types. The resistance rates of ST398 strains to gentamicin, tetracycline, levofloxacin,clindamycin and trimethoprim-sulfamethoxazole were significantly higher than those of ST59 strains (P<0.01).ST398 strains carried more abundant acquired resistance genes, including high carriage rates of tet(M) (95.00%),lnu(B) (75.00%), lsa(E) (90.00%) and dfrG (90.00%). Additionally, 3 strains carried the poxtA gene; while the resistance gene profile of ST59 strains was relatively simple. In terms of virulence characteristics, ST398 strains showed strong hemolytic activity; ST59 strains had stronger biofilm-forming ability and carried a more complex virulence gene profile, with significantly higher carriage rates of immune escape genes sak, scn, and enterotoxin genes seb, sek, seq compared to ST398 strains.

The main prevalent clones of MRSA in retail pork products in Hanzhong are ST59 and ST398. The different biological characteristics pose differential challenges to public health, requiring targeted monitoring and prevention measures.

To conduct a comprehensive biological characterization of an oxacillin-susceptible mecA-positive Staphylococcus aureus (OS-MRSA) strain isolated from a retail chicken sample, assess its virulence potential and molecular typing characteristics.

Staphylococcus aureus strain SAC10 was isolated from supermarket frozen whole-chicken samples. Identification was performed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and antibiotic resistance profiles and the mecA gene were detected by antibiotic susceptibility testing and polymerase chain reaction (PCR). Whole-genome sequencing analyzed resistance genes, virulence genes and molecular typing. Virulence phenotypes were assessed via hemolysis assays, biofilm formation assays, and Galleria mellonella infection models. Sequence alignment elucidated the regulatory mechanism of the mecA gene.

SAC10 was identified as ST59-t437-IVa(2B) OS-MRSA. It carried mecA but exhibited phenotypic susceptibility, with its resistance gene profile consistent with the antimicrobial susceptibility pattern. The genome harbored multiple virulence factors (hlgABC, seb, sek, seq, aur, sak, scn),demonstrating strong hemolytic activity and biofilm-forming capability. Galleria mellonella assays revealed moderate virulence (16.67% survival at 72 h). Insertion of ISSau3 into the upstream promoter region of mecA suppressed its expression, resulting in the susceptible phenotype.

As a foodborne OS-MRSA, SAC10 combines virulence with concealed resistance genes, posing potential health risks via the food chain. The insertion mutation in mecA causing genotype-phenotype discordance highlights the need to combine conventional susceptibility testing with molecular detection to prevent underdiagnosis. These findings provide a scientific basis for improved monitoring and risk assessment of foodborne OS-MRSA.

To establish a co-expression system combining episomal and integrative vectors, enhance the expression efficiency of antimicrobial peptides in Pichia pastoris, and address the issue of insufficient production caused by copy number limitations and expression instability.

The 2 kanamycin-resistant episomal vectors, pPICKαA-panARS-JS21T and pGAPKαA-panARS-JS21T, were constructed using the Kluyveromyces lactis panARS autonomously replicating sequence. These were co-electroporated with the integrative vector pPICZαA-JS21T into Pichia pastoris X-33. Positive transformants were selected on Zeocin plus G418 double-antibiotic plates. Shake-flask cultures were run for more than 120 h with methanol supplementation every 24 h to maintain induction. Secreted total protein was quantified by the Bradford assay, target bands were visualized by trimethylglycine-sodium dodecyl sulfate polyacrylamide gel electrophoresis (Tricine-SDS-PAGE), and antimicrobial activity against Staphylococcus aureus was measured by agar diffusion.

After 120 h of fermentation, the integrative plus episomal pGAPKαA-panARS-JS21T co-expression group yielded 107.22 µg/mL of extracellular total protein, 52% higher than 70.56 µg/mL of the integrative-only control. The corresponding inhibition-zone assay showed a 129% increase in antimicrobial activity (P<0.05). The integrative plus pPICKαA-panARS-JS21T group also achieved a 15.8% improvement over the integrative-only group.

A combined episomal/integrative co-expression strategy synergistically elevates JS21T antimicrobial peptide levels in Pichia pastoris, outperforming single-vector systems and offering a new route for high-level production of small peptide molecules.

To investigate the contamination status of Burkholderia gladioli in edible fungi in Yunnan Province from 2022 to 2024, perform whole-genome sequencing on isolated strains, and analyze the genetic characteristics of toxin-producing strains.

A total of 724 samples were collected from Yunnan Province.The isolated and identified strains were subjected to second-generation whole-genome sequencing to analyze their genetic characteristics and the presence of bon gene clusters related to bongkrekic acid biosynthesis.

The detection rate of Burkholderia gladioli in the 724 samples was 12.85% (97/724), the detection rates of Auricularia auricula and Tremella fuciformis were 13.20% (61/462) and 12.87% (26/202) (P>0.05), respectively, with no statistical difference (P<0.05). The contamination of this bacterium had obvious regional differences (P>0.05), and the detection rate in the circulation link had no difference. The 17 samples were found to contain Burkholderia gladioli pathovar cocovenenans carrying complete bon gene clusters, but with varying toxin-producing abilities, 2 highly toxic cocovenenans variants were identified. Phylogenetic analysis showed that the 97 isolates were distributed on multiple branches of the evolutionary tree, with some isolates from Auricularia auricula and Tremella fuciformis showing a clear tendency to cluster. The bon gene clusters were highly consistent with the core genome phylogenetic tree.

There are significant regional differences in the contamination of Burkholderia gladioli in commercially available Auricularia auricula and Tremella fuciformis across Yunnan Province. Targeted food monitoring shall be implemented in high-risk prefectures.

To establish a method for the determination of 7 kinds of organic solvent residues in tea polyphenols by headspace-gas chromatography (HS-GC), and conduct risk analysis.

A method for simultaneous determination of 7 kinds of organic solvent residues (n-hexane, methanol, dichloromethane, acetone,ethanol, trichloromethane and ethyl acetate) in tea polyphenols was established using a 50% N,N-dimethylacetamide solution as the matrix, separated by a DB-23 capillary column (60 m×0.32 mm, 0.25 μm), and detected by a flame ionization detector (FID).

HS-GC could effectively separate 7 kinds of solvents to be tested, with good intra day and inter day precision. The standard curve showed a good linear relationship within the concentration range under investigation, with limit of detection of 0.03–1.71 μg/g and limit of quantitation of 0.12–5.77 μg/g. At the same time, residue testing and risk analysis were conducted on 27 batches of tea polyphenol samples in the market.According to the regulations of Chinese Pharmacopoeia, methanol, ethyl acetate, n-hexane and ethanol were detected in some tea polyphenol samples. Among them, 33.33% of the samples had n-hexane and 14.81% of the samples had ethanol exceeding the standard. However, through the analysis of permissible daily exposure (PDE), the health risks caused by n-hexane and ethanol were relatively low.

This research method is simple, accurate, and suitable for the determination of 7 kinds of residual organic solvents in tea polyphenols.

To explore the performance differences of various maize seed tissues in genome extraction and nucleic acid testing to clarify the optimal choice and its impact on clustered regularly interspaced short palindromic repeats/associated protein 12a (CRISPR/Cas12a)-based detection system.

In this study, the genome extraction efficiencies of maize seed embryo, endosperm and whole kernel were compared. Through the conventional polymerase chain reaction (PCR) cascade CRISPR/Cas12a system, the extracted products from each part were amplified and identified, and the impact of the extracted genome on subsequent nucleic acid detection was evaluated. By comparing the DNA extraction efficiency, amplification effect and fluorescence signal intensity, the adaptability of samples from various parts in the test was verified.

There were differences in the efficiency of DNA extraction from different tissues of corn seeds. The genome concentration in the embryo was the highest,followed by the whole kernel, and the endosperm was relatively low, which was in line with the biological structural characteristics of corn seeds. The genomes in each part could be successfully amplified, and the cascade CRISPR/Cas12a system produced a clear positive signal. The qualitative detection limit of the method constructed in this study was 0.1 wt%, which met the detection requirements of genetically modified ingredients in most countries and regions.

Differences in extraction efficiency are found among maize seed tissues, but all parts supports effective nucleic acid amplification and CRISPR/Cas12a detection. In practical applications, tissue separation is not required; efficient and specific detection can be achieved using whole seeds or randomly selected samples. The method developed in this study does not require large-scale instrumentation and is suitable for on-site detection of genetically modified maize seeds, demonstrating potential for application in the safety screening of genetically modified food.

To establish a method for the determination of 5 kinds of nucleotides in aquatic products by high performance liquid chromatography.

After optimization of chromatographic conditions and selection of pretreatment conditions, the sample was extracted twice with 5% perchloric acid solution at 4 ℃, and then extracted with 0.01 mol/L KH₂PO₄ (containing 1.45 mmol/L tetrabutyl ammonium bisulfate,pH=5.0)-acetonitrile (95:5, V:V) was eluted by mobile phase, separated by C₁₈ (250 mm×4.6 mm×5 μm) column,detected by ultraviolet detector, and quantified by external standard method with standard curve.

The 5 kinds of nucleotides had a good linear relationship in the range of 0.1–100.0 μg/mL, and the correlation coefficient was greater than 0.999. The limits of detection and limits of quantitation were 1.0–2.0 mg/kg and 3.0–6.0 mg/kg,respectively, and the precisions were 2.00%–6.87%. The spike recoveries were 92.3%–105.6%, the intra-assay standard deviations were 0.63%–7.90%, and the inter-assay standard deviations were 1.72%–7.34%.

This method has high sensitivity and good repeatability, and can be used for the qualitative and quantitative analysis of 5 kinds of nucleotides in aquatic products.

To establish a method for detecting DNA in highly pigmented food samples by membrane-based improved cetyltrimethylammonium bromide (CTAB) combined with real-time fluorescence polymerase chain reaction (PCR).

Black sesame, tea seed meal and rapeseed meal were selected as samples. The optimized protocol employed 0.7 μm glass fiber membrane with 70% ethanol as the rinsing solution and 3 rounds of tris(hydroxymethyl)aminomethane ethylenediaminetetraacetic acid (TE) buffer elution. Pigment removal was achieved through membrane-specific adsorption and selective permeability. The extraction efficiency of the modified CTAB method was compared with that of the traditional CTAB method, and DNA purity and amplification efficiency were evaluated via real-time fluorescence PCR targeting endogenous genes.

The modified method demonstrated significantly superior DNA decolorization effects compared to the traditional CTAB method.Endogenous genes were successfully detected in all 3 kinds of samples, with DNA mass concentrations exceeding 100 ng/μL and cycle threshold (Ct) values ranging between 20 and 25. In contrast, the traditional CTAB method failed to achieve real-time fluorescence PCR amplification due to pigment residue.

The membrane-optimized CTAB method simplifies purification steps, enhances decolorization efficiency, and significantly improves the extraction and detection success rate of DNA from highly pigmented foods. This approach provides a reliable and efficient technical solution for food safety testing.

To establish a method for determination of fipronil and its metabolites in meat by amino functionalized magnetic nanomaterials purification-high performance liquid chromatography-mass spectrometry.

The samples were ultrasonically extracted with acetonitrile-water. The extract was purified by amino-functionalized magnetic nanoparticles, and then concentrated under nitrogen. The residue was dissolved in acetonitrile-water (7:3, V:V) to a final volume. The analyte solution was analyzed using a C₁₈ column with methanol and water as the mobile phase under negative electrospray ionization mode. The data was collected using the multi reaction monitoring mode. The samples were analyzed based on the external standard method.

Under the established conditions, the target substances were well separated and showed a good linear relationship within the range of 1.0–20.0 ng/mL, with a correlation coefficient (r²) greater than 0.99. The limit of detection was 0.2 µg/kg and the limit of quantitation was 0.5 µg/kg. Through spiked recovery experiments, the recovery rates at 3 spiked levels ranged from 79.94% to 94.52%, with relative standard deviations of 2.95% to 8.22%.

Compared with traditional pretreatment methods, the proposed method utilizes a magnetic suction frame to absorb magnetism,which can eliminate the centrifugation steps, save time, ensure good reproducibility and reduce detection costs. The proposed method can be used to determine fipronil and its metabolites in meat. The establishment method can provide technical support for monitoring the residues of fipronil and its metabolites in meat on the market supervision.

To investigate the conditions for inducing expression levels of α-L-rhamnose glycosidase RhaB2 and its conversion of rutin, thereby enhancing the conversion rate of rutin to isoquercitrin.

Single-factor experiments examined the effects of induction temperature, duration and inducer concentration on enzyme expression levels. The effects of pH, temperature, incubation time and enzyme loading on RhaB2-mediated rutin conversion were also investigated.

Optimal expression conditions for recombinant α-L-rhamnose glycosidase RhaB2 in Escherichia coli BL21(DE3) were: Induction temperature 28 °C;induction time 20 hours; IPTG concentration 0.1 mmol/L. The optimal temperature for rutin conversion was 50 °C,with an optimal pH of 5.0. Under these conditions, a 2-hour reaction at a 2:1 enzyme-to-substrate mass ratio achieved a conversion rate of 99.96%.

In this study, a highly efficient heterologous expression system for recombinant α-L-rhamnosidase RhaB2 is successfully constructed. Under the technological conditions where the mass ratio of the enzyme to the substrate is 2:1 and the reaction time is 2 hours, the conversion rate of rutin can reach 99.96%, thus enabling the highly efficient and targeted preparation of isorhamnetin.

To study the effects of nano-copper molybdate and nano-lithium molybdate on the browning of fresh-cut Malus.

The 3 groups of fresh-cut apples were immersed in deionized water,nano-copper molybdate and nano-lithium molybdate solutions for 30 minutes, respectively, and then left in the air.Samples were taken at 0, 1.5, 3.0 and 6.0 h to measure flesh browning and related physiological indicators (total phenol content, malondialdehyde content, flavonoid content, phenylalanine ammonia-lyase activity, and polyphenol oxidase activity).

After treatment with nano-copper molybdate and nano-lithium molybdate(within 0 to 6.0 hours), the flesh color of fresh-cut Malus did not change significantly compared to that at 0 hours,while the flesh of the control group Malus showed obvious browning at 1.5 hours. Compared with the control group,the degree of browning, malondialdehyde content, flavonoid content, phenylalanine ammonia-lyase and polyphenol oxidase activity of the treated group Malus were all significantly reduced.

Nano-copper molybdate and nano-lithium molybdate significantly delayed the browning rate of the Malus. This study provides a theoretical basis for the application of nano-copper molybdate and nano-lithium molybdate in the preservation of fresh-cut fruits.

To comparatively analyze the differences in phenolic substance content among 3 varieties of Lycium barbarum from different production areas in Ningxia.

A total of 36 Lycium barbarum samples of Ningqi No.1, Ningqi No.7 and Keqi No.608 from different production areas in Ningxia were collected. The differences in the content of flavonoids, phenolic acids, carotenoids and betaine in Lycium barbarum were monitored and analyzed, and identification model of Lycium barbarum from different production areas based on phenolic substances was constructed.

The flavonoids, phenolic acids, carotenoids and betaine in Ningqi No.1 Lycium barbarum from different production areas showed significant differences (P<0.05) among 4 production areas. The content of phenolic substances in the Hongshibao production area was significantly higher than that in other production areas. The flavonoids, carotenoids and betaine in Ningqi 7 Lycium barbarum showed significant differences among the 5 production areas. The content of phenolic substances in the Hongshibao production area was significantly higher than that in the other production areas. The flavonoids, phenolic acids and betaine in Keqi 608 Lycium barbarum showed significant differences among the 3 production areas. The content of phenolic substances in the Zhongning production area was significantly higher than that in other production areas. An identification model of Lycium barbarum from different production areas based on the orthogonal partial least squares discriminant analysis discriminant analysis method was established, and its overall correct discrimination rate was 100%.

There are significant differences in the content of phenolic substances among Lycium barbarum from different production areas in Ningxia. This study provides a reference basis for the development of functional components of Lycium barbarum and the comprehensive quality evaluation of Lycium barbarum from different production areas.

To establish a method for the determination of 9 kinds of stevioside compounds in aquatic products by ultra performance liquid chromatography-tandem mass spectrometry with isotope internal standard.

The sample was extracted with methanol aqueous solution (1:1, V:V), separated on a CSH C₁₈ chromatographic column, and eluted with a gradient. The sample was analyzed in multiple reaction monitoring mode using electrospray negative ionization mode and quantified by internal standard method.

The 9 kinds of stevioside compounds showed good linear relationships in the range of 0.1–100.0 ng/mL. The limits of detection were 2.0 µg/kg, and the limits of quantitation were 5.0 µg/kg. The spiked recoveries of the method at low, medium and high spiked levels showed that the recoveries were in the range of 90.16%–103.69% with the relative standard deviations of 2.24%–6.38%. The method was used to analyze aquatic products, with a detection rate of 12%.

The method is simple, efficient, and highly accurate and sensitive, making it suitable for the determination of 9 kinds of stevioside compounds in aquatic products.

To establish a quantitative analytical method for 17 kinds of triterpenic acid compounds in Poria cocos and investigate their content in samples from different regions.

A high performance liquid chromatography method was developed using an C₁₈ column with gradient elution (acetonitrile-0.1% phosphoric acid solution as the mobile phase). The flow rate was set at 1.0 mL/min, column temperature at 20 ℃, and injection volume at 20 μL. The 17 kinds of triterpenic acid compounds were quantified by wavelength switching mode, and the obtained data were subjected to analysis.

All 17 kinds of compounds exhibited good linearity (r>0.999) within their respective concentration ranges. The spike recovery rates ranged from 80.9% to 92.5%, with relative standard deviations below 5.0%. The limits of detection and limits of quantitation respectively were 0.343–2.839 μg/mL and 1.143–9.462 μg/mL.

The established high performance liquid chromatography method features simple sample pretreatment, high sensitivity, excellent stability and accuracy, making it suitable for the determination of 17 kinds of triterpenic acids in Poria cocos. This study provides a foundational basis for the development and utilization of functional components in Poria cocos.

To establish an inductively coupled plasma mass spectrometry (ICP-MS) for the determination of 19 kinds of elements in Plukenetia volubilis Linneo, evaluate the elemental distribution characteristics and quality differences of quality variance element of Plukenetia volubilis Linneo from different producing areas.

A total of 33 batches of Plukenetia volubilis Linneo samples from Xishuangbanna,Honghe, Puer (Yunnan Province), Thailand and Laos were subjected to microwave digestion. The content of 19 kinds of elements including Co, Ni and As were determined by ICP-MS. The method validity was verified by linear relationship, precision, repeatability and recovery rate, and principal component analysis and correlation analysis were performed.

The method showed good linearity (r²>0.9990), excellent precision (relative standard deviation<2%) and reliable accuracy (spiked recovery rate: 90.3%–116.8%). The cumulative variance contribution rate of principal component analysis reached 82.854%, and the characteristic elements of Plukenetia volubilis Linneo were identified as Zn, Cd, Sr, Mn, Cr, Pb and Ti. Correlation analysis indicated strong correlations among the elements.

The ICP-MS method can accurately and rapidly determine the content of 19 kinds of elements in Plukenetia volubilis Linneo, providing a reliable approach for evaluating the quality of Plukenetia volubilis Linneo from different producing areas. The analysis of characteristic elements also offers important reference for improving the quality standards of Plukenetia volubilis Linneo.

To optimize ultrasonic assisted enzymatic extraction of antimicrobial peptides from Carassius auratus scales.

In this study, the diameter of inhibition zone against Escherichia coli and peptide recovery rate were used as evaluation indicators. The enzymatic effects of pepsin, trypsin, papain, and neutral protease on Carassius auratus scales were compared and analyzed to screen the optimal enzyme for enzymolysis.Through single-factor experiments, the effects of substrate concentration, enzyme activity, enzymolysis time, and ultrasonic power on the extraction efficiency of antimicrobial peptides from crucian carp scales were systematically analyzed. On this basis, three key factors (enzyme activity, enzymolysis time, and ultrasonic power) were selected for orthogonal optimization experiments.

Pepsin was identified as the optimal enzyme for enzymolysis. Under the enzymatic hydrolysis process with a substrate mass concentration of 200 mg/mL, enzymatic hydrolysis time of 4 h,ultrasonic power of 120 W, and enzyme activity force of 5000 U/g, the antibacterial effect of the obtained antimicrobial peptide was the best, with a inhibition zone diameter of (2.66±0.66) cm against Escherichia coli and a short peptide recovery rate of 22.52%±1.64%.

The ultrasonic assisted enzymatic extract of antimicrobial peptides from Carassius auratus scales provides a critical theoretical foundation for subsequent separation and purification.

To explore the microbial diversity among 4 kinds of Kefir granules from different regions.

Traditional separation and purification, molecular biology technology, high-throughput sequencing and other methods were used to explore the microbial diversity in Kefir granules from different sources. The 4 kinds of Kefir yogurt were fermented with 8% inoculum. The protein content, total acid, pH and water holding capacity of yogurt were analyzed and compared, and their texture characteristics were determined by texture analyzer.

At the species level, the dominant fungi shared by Kefir granules from 4 kinds of regions were Kazachstania unispora and Kluyveromyces marxianus, and the dominant bacteria were Lactobacillus kefiranofaciens and Lactobacillus kefir. There were a total of 35 operational taxonomic units (OTUs) in fungi, among which 4 kinds of Kefir granules had a total of 3 OTUs. There were 12 bacterial OTUs in total, of which 3 were common to the 4 kinds of Kefir granules. German fermented yogurt had good viscosity but with high acidity, and Chinese fermented yogurt had high chewiness but with poor water holding capacity. Russian fermented yoghurt had good water holding capacity and most texture properties, but its chewiness was poor. Fermented milk in the United States had the highest protein content, but poor texture properties.

This study reveals the microbial diversity of Kefir granules from different sources and its significant impact on the quality of yogurt. Chinese Kefir granules, with Kluyveromyces maximus as the dominant strain, endow yogurt with unique flavor and high chewiness. German samples show excellent stickiness,but their too high acidity required process optimization. The differences in microbial communities directly lead to regional characteristics in the physicochemical and textural properties of yogurt, providing a theoretical basis for the targeted screening of Kefir agents.

To explore the two-step enzymatic hydrolysis process for preparing walnut meal enzymatic peptides, and study their in vitro antioxidant and anti-fatigue activities.

Single-factor experiments and response surface experiments were used to determine the optimal two-step enzymatic hydrolysis method for preparing walnut meal enzymatic peptides. The antioxidant capacity was evaluated by determining the scavenging effects on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals, hydroxyl radicals, and superoxide anion radicals, as well as the total reducing power. The anti-fatigue effect was assessed using a mouse swimming exhaustion test.

The optimal combination for preparing walnut meal enzymatic peptides through two-step enzymatic hydrolysis was as follows: Alkaline protease at 2000 U/g, pH of 9.0 for alkaline protease, and flavor protease at 1000 U/g. Compared with ascorbic acid, the half-maximal inhibitory concentration for DPPH radical scavenging was (0.25±0.01) mg/mL, the half-maximal inhibitory concentration for hydroxyl radical scavenging was(0.96±0.01) mg/mL, and the half-maximal inhibitory concentration for superoxide anion radicals scavenging was(0.25±0.01) mg/mL, indicating that walnut meal enzymatic peptides had certain in vitro antioxidant activity. The mouse experiments revealed that walnut meal enzymatic peptides had no negative effects on mice and could effectively prolong their swimming time, maintain the levels of glycogen and antioxidant enzymes in the body, and reduce the accumulation of serum metabolic waste and peroxides, demonstrating a certain anti-fatigue effect.

The two-step enzymatic hydrolysis method is successfully used to prepare walnut meal enzymatic peptides with in vitro antioxidant and in vivo anti-fatigue activities, which have great application potential in the development of health foods or functional food ingredients with antioxidant and anti-fatigue functions.

To investigate the contamination levels and dietary risks of per- and polyfluoroalkyl substances (PFASs) in seafood products from Binzhou City.

A total of 109 seafood samples were collected. A ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established for quantitative detection of 23 kinds of PFASs. Population health risks from seafood-derived PFASs intake were assessed using hazard ratio (HR) models.

The 9 kinds of PFASs were detected in seafood, with perfluorooctanoic acid (PFOA) exhibiting a detection rate of 100% and accounting for 82.2% of total mass concentration—significantly higher than other PFASs. Further analysis revealed significant compositional differences and species-specific distribution patterns in PFASs contamination levels: PFOA was the predominant contaminant in bivalve mollusks and portunus trituberculatus; perfluorotridecanoic acid (PFTrDA) accounted for the highest proportion of total PFASs in Litopenaeus vannamei shrimp; and perfluorooctane sulfonic acid (PFOS) exhibited the highest content in mantis shrimp. PFOA distribution varied significantly across different tissues of the portunus trituberculatus, with apparently higher accumulation in crab roe than in other tissues. Dietary exposure risk assessment further revealed that both PFOA and PFOS’ HR was below 1.

PFOA is the primary PFASs contaminant in seafood from Binzhou City. PFASs accumulation exhibits species specificity across seafood, with portunus trituberculatus displaying the highest total PFASs content, primarily concentrated in crab cream. No evidence of human health risks from PFOA and PFOS intake via seafood consumption has been identified.

To understand the contamination status of Listeria monocytogenes in meat and meat products in Jiangsu Province.

From 2015 to 2024, a total of 5705 different types of meat and meat products were collected from multiple links including agricultural product markets, supermarkets and restaurants in 13 prefecture-level cities in Jiangsu Province to detect Listeria monocytogenes according to the protocol of National food contamination and hazardous factors risk monitoring. The results were statistically analyzed by SPSS 27.0 software.

Among the 5705 samples, 328 were tested positive for Listeria monocytogenes, with an overall detection rate of 5.7%. The detection rate of raw meat and its products was significantly higher than that of cooked meat and its products (χ²=91.717, P<0.001). There were significant differences in the detection rates among pork,beef, chicken and duck samples (χ²=11.510, P=0.009). Besides, there were significant differences in the detection rates among fresh meat, chilled meat and frozen meat samples (χ²=89.652, P<0.001). The detection rate of samples from the circulation link was significantly higher than that of the catering link (χ²=10.388, P=0.001). There were significant differences in the detection rate of Listeria monocytogenes among samples collected from agricultural product markets, supermarkets, and online stores (χ²=6.038, P=0.049).

Contamination with Listeria monocytogenes continues to exist in meat and meat products in different regions of Jiangsu Province, which has potential risks. Surveillance and regulation should be enhanced to prevent the occurrence of related foodborne diseases.

To investigate the contamination level of phthalate esters (PAEs) plasticizers in marketed liquors, compare the content of PAEs in different types of alcohol samples and samples collected from different sampling links, evaluate the exposure risk of citizens of Hanghzou.

The contamination status of PAEs in 97 marketed liquors samples was investigated using gas chromatography-tandem mass spectrometry (GC-MS/MS),and a point estimate method was applied to assess the dietary exposure of Hangzhou residents to PAEs.

The 7 kinds of plasticizers including dimethyl phthalate (DMP), diethyl phthalate (DEP), diisobutyl phthalate (DIBP),dibutyl phthalate (DBP), bis(2-ethoxyethyl) phthalate (DEEP), bis(2-ethylexyl) phthalate (DEHP) and bis(2-ethylhexyl) terephthalate (DOTP) were detected in liquors, the detection rates of DBP was the highest, it was 67.0%, but the detection rates of DEEP and DOTP were only 3.1% and 1.0%. The mean concentration values of DEP,DEEP and DOTP were blow the limit of detection (LOD). The 5 sample was detected above the limit value of DBP.The types, detection rate and concentration of the detected PAEs were different among the 6 kinds of liquors;meanwhile, the detection rate and concentration of PAEs were also different among the samples collected from the 3 kinds of different sampling links. The mean dietary exposure values for DMP, DIBP, DBP and DEHP were 0.01, 0.02,0.08 and 0.006 μg/(kg bw·d), hazard index (HI) was 1.2×10^–3.

The max exposure values of DIBP,DBP and DEHP in liquors are 0.1, 0.9 and 0.1 μg/(kg bw·d), respectively, all of which are less than the tolerable daily intake (TDI), HI is far less than 1 and the health risk of PAEs caused to drinking is low.

To investigate the heavy metal pollution and evaluate the dietary exposure risk of soy sauce in 2024.

This study collected 180 portions of soy sauce, including 139 portions of pre-packaged soy sauce and 41 portions of bulk soy sauce. Content of 7 kinds of elements including lead (Pb), cadmium (Cd),chromium (Cr), total arsenic (As), manganese (Mn), nickel (Ni) and copper (Cu) were determined by national standards. The pollution degree of Pb and As was evaluated by single-factor pollution index method (P_i) and nemerow comprehensive pollution index method (P_N). The dietary exposure risk was evaluated by target hazard quotient (THQ) and total target hazard quotient (TTHQ).

The heavy metals were detected in all soy sauces,but there were differences in the types of heavy metals. According to the limited requirements of GB 2762—2022 National food safety standard-Limits of contaminants in food (Pb≤1.0 mg/kg and As≤0.5 mg/kg), only Pb in the 139 portions of pre-packaged soy sauce was detected to have unqualified samples, with an unqualified rate of 2.16%.The average content of other detected heavy metals was sorted as Mn>Ni>Pb>Cr>Cu>As>Cd. The 41 portions of bulk soy sauce Pb and As met the limited quantity requirements. And the average content of other detected heavy metals was sorted as Mn>Ni>Cr>Pb. Out of 180 soy sauce samples, 3 pre packaged soy sauce samples had reached the pollution level for Pb, while the rest were safe. P_N showed that pre packaged soy sauce Pb was mildly contaminated,bulk soy sauce Pb was close to the warning line, and As was safe. The THQ and TTHQ values of heavy metals in all soy sauce were less than 1.

Most soy sauces have low contamination levels, only a small number of soy sauces are in mild and moderate contaminated. Therefore, the quality monitoring of soy sauce condiments should be strengthened. Under normal intake, the risk of dietary exposure of heavy metals in soy sauce is acceptable.

To understand the distribution characteristics of microorganisms and their pathogenic factors in commercially available foods in Wuxi City from 2012 to 2024.

According to the requirements of the Wuxi food safety risk monitoring work plan for each year, randomly select food products sold in Wuxi for testing, and used the methods recommended in the provincial work manual for each year to inspect the samples.

From 2012 to 2024, a total of 2734 food samples were tested for foodborne pathogens, with a positive detection rate of 11.19%; the 12 kinds of pathogenic bacteria were detected, with Vibrio parahaemolyticus having the highest detection rate (15.81%), followed by Bacillus cereus (10.21%) and Cronobacter genus (7.47%), with statistically significant differences (χ²=577.14, P<0.001); the detection rate was highest in 2015 (17.68%) and lowest in 2020 (2.35%), with a statistically significant difference (χ²=62.59, P<0.001); pathogenic bacteria were detected in 8 kinds of food, with higher detection rates in aquatic products (25.5%) and infant food (14.3%), and the difference was statistically significant (χ²=92.56, P<0.001); in different sampling stages, the detection rate of pathogenic bacteria in super large restaurants in the catering service stage was the highest (25.00%), and the detection rate of pathogenic bacteria in agricultural markets in the circulation stage was the highest (17.54%), with statistical significance (χ²=53.80, P<0.001). The 261 aquatic products were tested for 5 kinds of parasites, with a detection rate of 9.90% for nematodes; jaw mouth nematodes (third stage larvae) were detected in one sample of eels, with a detection rate of 0.80%.

The food sold in Wuxi City is contaminated to some extent by microorganisms, with a diverse distribution of contamination and a phenomenon of mixed contamination.Particularly, the hygiene issues of aquatic products, infant cereal supplementary foods, farmer’s markets and catering units deserve attention. It is recommended to carry out monitoring of key links and key foods, and in the later stage, it is suggested to expand the monitoring scope and samples to prevent the occurrence of foodborne diseases and food poisoning.