Objective To optimize the enzyme-assisted extraction process of Eucommia ulmoides leaf extract, and evaluate its antioxidant and hepatoprotective activities. Methods Using Eucommia ulmoides leaves as raw material, the enzyme-assisted extraction technique was employed to optimize the extraction process. The antioxidant activity of the extract was evaluated through 1,1-diphenyl-2-picrylhydrazine (DPPH) radical scavenging rate, hydroxyl radical scavenging rate, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging rate, and total antioxidant capacity assays. The hepatoprotective activity was assessed using a zebrafish model. Results Under the conditions of a solid-to-liquid ratio of 1:20 (g:mL), enzymolysis temperature of 50 °C, enzymolysis time of 4 h, and enzyme dosage of 3%, the yield of Eucommia ulmoides leaf extract was 32.15%±0.36%, with a theoretical yield of 31.781%. The small difference between the actual and theoretical yields indicates the reliability of the extraction parameters. In vitro antioxidant activity tests showed that, within the experimental mass concentration range, the extract exhibited significant antioxidant activity, effectively scavenging DPPH radicals, hydroxyl radicals, and ABTS radicals. Zebrafish experiments demonstrated that the extract at mass concentrations of 100 μg/mL and 200 μg/mL protected against thioacetamide (TAA)-induced liver injury, indicating notable hepatoprotective activity. Conclusion The Eucommia ulmoides leaf extract obtained through enzyme-assisted extraction possesses excellent antioxidant and hepatoprotective activities. This study provides technical support for the further application and promotion of Eucommia ulmoides leaves in the food field.

Objective To establish a rapid colorimetric method for the detection of histamine in fish samples based on the oxidase activity of Ag₃PO₄ nanozyme. Methods Ag₃PO₄ nanoparticles were prepared by the hydrothermal method. Utilizing their oxidase catalytic activity, with CH₃COONa as the buffer system and 3,3',5,5'-tetramethylbenzidine as the oxidation substrate, a rapid colorimetric detection method for histamine in fish was established. Results The detection time of this method was about 100 seconds. The limit of detection was 0.58 mg/L, indicating high detection sensitivity. In the detection of multiple competitive targets, this method showed good specificity for histamine molecules. In the spiked experiments on actual samples, the spiked recovery rate of this method ranged from 104.24% to 108.30%, and the relative standard deviations were from 1.81% to 3.44%, which had good detection accuracy. Conclusion This method demonstrates the advantages of being intuitive, rapid, highly sensitive and having good specificity. It can adapt to the complex daily detection environment and provides a new idea for the detection of histamine in fish meat.

Objective To investigate the effects of Tuo tea flavonoids on D-galactose-induced aging mice in delaying aging and inhibiting inflammation. Methods The anti-aging efficacy of Tuo tea flavonoids were evaluated by measuring weight change, organ index and specific indicators in serum and tissue samples of aged mice treated with Tuo tea flavonoids. Results Tuo tea flavonoids could effectively prevent weight loss caused by aging, and also had a significant effect on preventing the shrinkage of key organs such as the thymus and brain. In addition, the compound also increased the levels of total antioxidant capacity (T-AOC), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in the blood and liver of aging mice, while reducing the concentrations of malondialdehyde (MDA) and nitric oxide (NO). At the same time, the levels of inflammation-related interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) cytokines in serum of aging mice were decreased. Further studies showed that in liver tissues, the expression levels of neuronal nitric oxide synthase (nNOS), endothelial nitric oxide synthase (eNOS), manganese superoxide dismutase (Mn-SOD), copper zinc superoxide dismutase (Cu/Zn-SOD) and catalase (CAT) mRNA increased. The inducible nitric oxide synthase (iNOS) showed a decreasing trend. Especially when the dose reached 100 mg/kg, the Tuo tea flavonoids showed better effects than the same dose of vitamin C. Conclusion As a natural product with potential life-prolonging function, the Tuo tea flavonoids show good biological activity.

Objective To investigate the content of 16 kinds of rare earth elements in commercial vegetables and evaluate the health risks caused by the intake of rare earth elements in vegetables for users in Gansu Province. Methods Samples from 6 categories were collected from 13 areas in Gansu Province, and the content of the 16 kinds of rare earth elements were measured by inductively coupled plasma mass spectrometry. According to the health risk analysis method recommended by United States Environmental Protection Agency (USEPA), the allowable daily intake (ADI) was used to assess the health risk of rare earth elements in commercial vegetables. Results The earth elements of vegetables sold in Gansu were mainly Sc, Y, Ce, La, Nd, Pr, with detection rate exceeds 50%, the total content of rare earth elements in the 6 types of vegetables was 0.1764 mg/kg, ranked from high to low as follows: Melon and fruit vegetables>leafy vegetables>stem vegetables>solanaceous fruit vegetables>root vegetables>bean vegetables. There were no significant differences in the content of rare earth elements among different vegetable categories (P>0.05), but significant differences were observed among vegetables from different areas (P<0.05). The health risks posed by the 16 kinds of rare earth elements varied among different population groups, with adult males and females exhibiting higher risks than children. The daily intake of rare earth elements through vegetable consumption was 0.0025 mg/(kg d), which was below the reference value of 0.07 mg/(kg d). Conclusion The content of rare earth elements in commercial vegetables in Gansu Province is low. The intake of rare earth elements through vegetables by residents will not pose a risk to human health.

Objective To explore the effects of ultrasonic synergistic enzymatic hydrolysis on the antioxidant activity and structure of donkey milk casein, optimize the process parameters of composite treatment, and analyze the promotion mechanism of ultrasonic pretreatment on the enzymatic hydrolysis process. Methods Using donkey milk casein as raw material, the ultrasonic parameters (200 W, 20 min, 6 s/6 s intermittency ratio) were optimized by single factor experiment, the neutral protease and trypsin (the mass ratio was 2:1) were screened, and the enzymatic hydrolysis conditions were optimized by response surface method (enzyme addition amount 4.86%, 55.28 °C, pH 7.76). The changes of protein molecular weight, secondary structure and functional groups were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and infrared spectroscopy. The antioxidant indexes such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging rate were determined. Results Ultrasonic synergistic enzymatic hydrolysis resulted in antioxidant ability of 69.77% and a 65.3% increase in Fe³⁺ reducing capacity, which was significantly better than that of the single treatment. The structure showed that the α-helix decreased to 26.70%, the random coil increased to 28.35%, the aromatic amino acids were exposed, the sulfhydryl groups were oxidized to disulfide bonds, and the molecular weight was reduced. The predicted value of the response surface model was in good agreement with the measured value (R²=0.9937). Conclusion The results of ultrasonic pretreatment significantly improves the antioxidant activity by destroying the structure of protein micelles and releasing antioxidant short peptides in synergy with enzymes, which provides a reference process parameter for the production of high value-added donkey milk antioxidant products, which is helpful to promote the development of donkey milk industry and improve the economic value of donkey milk.

Objective To analyze the characteristics of foodborne disease outbreaks in schools in Zibo City from 2019 to 2023. Methods The school food-borne disease outbreaks reported in Zibo City from 2019 to 2023 were collected through the national foodborne disease outbreak surveillance network for descriptive analysis. Results From 2019 to 2023 a total of 23 school foodborne disease outbreaks were reported, with a total of 337 cases, 35 hospitalized, and no death. Summer and autumn were the most common seasons. The incidents with clear pathogenic factors accounted for 34.78% (8/23), and the incidents caused by microorganisms and their toxins accounted for 75.00% (6/8). Staphylococcus aureus and its enterotoxin were the main pathogenic factors, accounting for 33.33% (2/6) of the outbreaks of microorganisms and their toxins. The most common causes of food were mixed food and other foods, accounting for 30.43% (7/23) and 26.09% (6/23), followed by food products, meat and meat products, accounting for 17.39% (4/23) and 13.04% (3/23). The main source of food was the school canteen (73.91%, 17/23). The main triggering factors were multiple factors, followed by the misuse of poisonous plants. Conclusions Microorganisms and their toxins are the main factors causing foodborne disease outbreaks in schools. Summer and autumn are the high incidence seasons. It is necessary to strengthen the food safety risk control of school canteens and strengthen the collaboration of multi-departments to reduce the occurrence of foodborne disease outbreaks in schools.

Mycotoxins are secondary metabolites produced by fungi, which accumulate in the food chain and enter the human body, endangering human health. In recent years, nanozymes with controllable morphology and enzyme-mimicking activity have shown significant advantages in the detection of mycotoxins. This paper mainly summarized the application research of nanozyme biosensors in the detection of mycotoxins, divided nanozymes into metal oxide-based, noble metal-based and carbon-based nanozymes according to the material components, analyzed the dynamic regulation mechanism of nanostructure parameters (including size, morphology, surface modification) on enzyme-mimicking activity, and then explored the technical advantages of nanozymes in colorimetric, fluorescence, electrochemical and Raman detection, revealing its application potential in the rapid detection of mycotoxins. In addition, this paper prospected the application of biosensors constructed by nanozymes in the detection of mycotoxins, aiming to provide theoretical support and technical foresight for the application of nanozymes in the field of food safety detection, and it was expected to provide guidance for the industrial development of the detection field.

Objective To establish a rapid visual detection method for Aspergillus niger in Zea mays L. by loop-mediated isothermal amplification (LAMP) technology. Methods Based on LAMP technology, specific primers targeting the key ochratoxin A (OTA) biosynthesis gene OTAhal were designed. Through screening of the primers and optimization of conditions such as primer sequence, primer ratio, reaction temperature and visual dye, the optimal detection conditions were determined. Using the total DNA of Aspergillus niger and artificially contaminated corn samples as templates, the sensitivity of the detection method and the feasibility of its practical application were validated. Results The optimal primer ratio was 8:4:1, the optimal reaction temperature was 64 °C, and the method could complete the amplification of target DNA within 30 minutes. The color of the positive sample changed from violet to blue-purple. This method could detect DNA concentrations as low as 6.87×10⁻³ ng/μL. When applied to actual Zea mays L. sample testing, it achieved a detection limit as low as 10¹ spores/mL. Conclusion This method is simple to operate, highly sensitive, and does not require sophisticated instruments. It can be applied to the detection of OTA in actual Zea mays L. samples, indicating broad application prospects.

Objective To determine the content of 27 kinds of inorganic elements in commercially available Solanum tuberosum L. in Qinzhou City and evaluate the situation of heavy metal pollution. Methods Quantitative analysis of 27 kinds of inorganic elements in Solanum tuberosum L. was conducted using the inductively coupled plasma mass spectrometry method from GB 5009.268—2016 National food safety standard—Determination of multiple elements in foods. The safety of the samples and the distribution of characteristic elements were comprehensively evaluated by combining the single-factor pollution index method, Nemerow comprehensive index method, and chemometrics based on the toxicity of the elements. Results The commercial Solanum tuberosum L. from Qinzhou City contained abundant trace elements, including the essential constants of human body such as Na (7.50-458.20 mg/kg), Mg (66.40-429.40 mg/kg), K (1620.80-7397.60 mg/kg), Ca (15.00-123.60 mg/kg); essential trace elements such as Mn (0.46-5.16 mg/kg), Fe (3.00-142.10 mg/kg), Cu (0.24-1.12 mg/kg); hazardous elements such as Pb (0-0.08 mg/kg), Cd (0-0.03 mg/kg), As (0-0.08 mg/kg), Cr (0-0.32 mg/kg). The hazardous elements Hg, Sn, Ni were not detected. The content of potentially harmful elements was low, indicating good safety. Single-factor pollution index and Nemerow comprehensive index analyses demonstrated that the single-factor pollution index values and Nemerow comprehensive index values for Pb, Cd, total Hg, total As, and Cr in all samples were less than 0.7, categorizing them as excellent grade with safe pollution levels. Principal component analysis identified Li, Al, Ti, V, Cr, Mn, Fe, As, Mg, K, Cu, Zn, Na, Ca and Sr as characteristic inorganic elements. Cluster analysis classified the samples into two major categories. Conclusion The Solanum tuberosum L. are sold in the market in that city, which has a very low content of harmful elements and a low degree of pollution, and the content does not exceed the limit requirements of GB 2762—2022 National food safety standard—Maximum levels of contaminants in foods. Therefore, all the tested Solanum tuberosum L. samples are safe food, and their growing environment is not polluted by heavy metals.

Objective To explore the application of the combination of real-time fluorescence quantitative polymerase chain reaction (qPCR) and droplet digital polymerase chain reaction (ddPCR) in the quantitative detection of meat adulteration. Methods This study employed qPCR and ddPCR technologies to develop a detection system with specific primers and probes for beef, lamb and pork samples, aiming to assess meat adulteration in the Beijing market. Results The experimental results revealed that the sample “Chang 5” contained adulteration of lamb and pork at a ratio of 17:10. qPCR demonstrated high sensitivity and specificity in qualitative detection, while ddPCR enabled absolute quantification of adulteration proportions. The combination of these 2 methods significantly improved detection accuracy. Conclusion The established qPCR-ddPCR combined method exhibits high sensitivity and specificity, making it suitable for rapid and precise detection of meat adulteration. This approach provides reliable technical support for food safety regulation.