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 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 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.

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 optimize the mixed acid extraction process of pectin from Akebia trifoliate peel and evaluate the structure, and antioxidant properties of pectin. Methods Using Akebia trifoliate peel as raw material, which was extracted by the mixed acids hydrolysis. The effects of the types of inorganic acids, the volume ratio of the mixed acid, solid-to-liquid ratio, pH, extraction time and temperature were studied, and Box-Behnken response surface method was used to optimize the extraction process parameters on the basis of single factor experiment. The structure of the peel pectin of Akebia trifoliate obtained under the optimal extraction conditions was characterized by ultraviolet-visible spectroscopy (UV-Vis) and Fourier transform infrared spectroscopy (FT-IR), and its antioxidant activity was investigated. Results The optimal extraction conditions were: The volume ratio of the mixed acid [V(citric acid):V(sulfuric acid)] 2:1, solid-to-liquid ratio 1:30 (g:mL), pH value 1.0, extraction time 2.0 h and temperature 94 ℃, and the extraction rate reached 14.22%, which were about 1.24% and 4.17% increase compared with single sulfuric acid and citric acid, respectively. FT-IR showed that the absorption peaks of sulfuric acid and citric acid extraction of pectin (CSEP) were more consistent with its structural characteristics than sulfuric acid extraction of pectin (SEP) and citric acid extraction of pectin (CEP) at 1754 cm^-1 and 1624 cm^-1, and its content of galacturonic acid (81.94%) and degree of esterification (82.41%) more higher. CSEP own superior antioxidant biological activity, and the half maximal inhibitory concentration (IC₅₀) for hydroxyl radical of CSEP was lower than that of commercial pectin (CP), which were 2.248 mg/mL and 4.114 mg/mL, respectively. Conclusion Using the mixed acid to extract pectin from Akebia trifoliata peel has good improved on extraction rate, content of galacturonic acid and antioxidant activity.

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 protective effects of ethanol extract of Chuangxiong tea on the 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH) (1 mmol/L) on oxidative stress injury of proximal renal tubule epithelial cells of pigs. Methods LLC-PK1 cells were co-cultured with ethanol extract of Chuanxiong tea (labeled CXTEE) with different mass concentrations ranging from 10 to 100 μg/mL for 24 h, and then placed in Dulbecco's modified eagle medium (DMEM) containing AAPH for 4 h to establish the cell damage model. The cell survival rate was measured by tetramethyl azazole blue (MTT) method. The content of malondialdehyde (MDA) and the level of total reactive oxygen species (ROS) were determined by thiobarbituric acid colorimetry and 2',7'-dihydrodichlorofluorescein yellow diacetate (DCFH-DA) probe technique, respectively. In addition, the activity of several antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione S-transferase (GST), γ-glutamylcysteine synthetase (γ-GCs), and the concentration of glutathione (GSH), were also evaluated using specific kits. Results The results showed that the cells pretreated with CXTEE showed a higher survival rate, and the total ROS level and MDA production in the cells were significantly reduced. At the same time, the extract also enhanced the activity of antioxidant enzymes (such as CAT, SOD, GSH-Px and GST) in the damaged cells, promoted the activity of γ-GCS and increased the content of GSH. Further experiments showed that CXTEE could also up-regulate the mRNA expression levels of SOD, GSH-Px and CAT in oxidative damage LLC-PK1 cells. Conclusion The ethanol extract of Chuangxiong tea may reduce the levels of MDA and ROS by strengthening the antioxidant defense system of cells, thus alleviating the oxidative stress damage caused by AAPH to LLC-PK1 cells. This study can provide a basis for further application and development of Chuangxiong tea.

Objective To construct a carbon nanotube-poly(neutral red) modified electrode for the competitive electrochemical rapid detection of putrescine in Procambarus clarkii samples. Methods Putrescine was selected as a freshness indicator for Procambarus clarkii. A carbon nanotube-poly(neutral red) modified electrode was designed for putrescine detection. The relationship between the electrochemical behavior of the electrode and the concentration of putrescine was explored, and its application in electrochemical sensing of putrescine was investigated. After optimizing factors such as scan rate and electrolyte pH, the putrescine content in Procambarus clarkii was determined. Recovery experiments were conducted, and the results were compared with high performance liquid chromatography. Results The carbon nanotube-poly(neutral red) modified electrode exhibited a significant electrochemical inhibition effect towards putrescine, with a notable inverse relationship between the concentration of putrescine and the peak current of the electrode. The linear range was described by the equation ΔI=3.8ln[c_(PUT)]+8.3, with a correlation coefficient of r=0.99. When applied to the detection of putrescine in crayfish samples, the results obtained by this method were highly consistent with those obtained by the high performance liquid chromatography. Conclusion The method can be employed for the detection of putrescine concentration in Procambarus clarkii and serves as a biosensor for putrescine, a freshness indicator of Procambarus clarkii.

Objective To explore the application areas of rapid detection technology for core quality indicators in cheese and its products using near-infrared spectroscopy (NIRS), and validating the feasibility of NIRS for rapid testing of cheese quality parameters. Methods Four types of common processed cheese products (cheese sticks, cheese slices, cream cheese, Mozzarella) were selected for experimentation and divided into modeling and validation sets; modeling experiments were conducted using samples from the modeling set on a single-brand instrument; synchronous national standard detection and multi-instrument NIRS detection comparative analysis were performed using instruments from 4 different manufacturers on the validation sets. Results For modeling, multidimensional prediction models for core indicators (protein, fat, moisture, pH) were successfully constructed by comparing the modeling mechanisms of algorithms like partial least squares regression (PLSR), with the coefficient of determination exceeding 0.85. For validation, the average deviations between the NIRS detection results (protein, fat, moisture) obtained using 4 kinds of NIRS spectrometers on different cheese products and those determined by national standard methods met equivalence requirements except for the protein deviation (>10%) of Mozzarella on instrument No.1; precision also met the requirements of national standard methods. Conclusion The application of NIRS spectroscopy equipment for rapid detection of core quality indicators in cheese and its products is feasible; NIRS spectroscopy technology can serve as an effective supplement to traditional chemical detection methods for rapid analysis of cheese composition, offering greater potential for high-efficiency, low-cost, and environmentally friendly testing.