Objective To investigate the effects of different storage methods on the quality safety of high-moisture harvested Zea mays L.. Methods The Zhengdan 958 (ZD958) Zea mays L. variety was selected for the experiment, and the Zea mays L. harvested under the same moisture content was stored as ear Zea mays L. and grain Zea mays L.. Changes in fungi species, quantity, and mycotoxin content were measured. Results Predominant fungi during Zea mays L. storage were Fusarium, Aspergillus, and Penicillium. In the early stage of storage, the dominant fungal genus was Fusarium, and with the extension of storage time, the dominant fungal genera changed to Aspergillus and Penicillium; with the increase of storage days, the total number of fungi in Zea mays L. stored in ear and grain storage showed a trend of first increasing and then decreasing. The number of fungi in Zea mays L. stored in ears was significantly lower than that in Zea mays L. stored in grains (P<0.05). During the storage period of 10-100 days, the number of fungi in Zea mays L. stored in ears decreased by 90.3%-98.6% compared to Zea mays L. stored in grains; with the increase of storage days, except for gibberellin in Zea mays L. kernels stored in ear, the content of vomitoxin and gibberellin in Zea mays L. showed an increasing trend. The content of vomitoxin and gibberellin in Zea mays L. stored in ears was significantly lower than that in Zea mays L. stored in grains (P<0.05). And with the increase of storage days, the difference in the content of vomitoxin and gibberellin in Zea mays L. under the two storage methods increases. Conclusion After high-moisture harvesting, ear storage can reduce fungi quantity and mycotoxin content, ensuring the quality safety of Zea mays L..

Objective To study the effects of deep eutectic solvent (DES) on the absorbance of tea polysaccharide by visible spectrophotometry, and establish a fast and efficient method for the determination of tea polysaccharide. Methods Choline chloride/DL-tartaric acid was used as the extraction solvent of tea polysaccharide. The influence of DES on the determination of tea polysaccharide content in anthrone sulfuric acid and phenol-sulfuric acid 2 kinds of detection methods was investigated. The linear relationship, precision, stability, repeatability and standard recovery rate of the 2 kinds of detection methods were compared. Results The best method for the determination of tea polysaccharides was phenol-sulfuric acid method, the optimal detection wavelength was 484 nm, and the absorbance had a good linear relationship with glucose concentration between 20 and 100 μg/mL. The precision relative standard deviation (RSD) of this method was 0.10%, the stability RSD was 0.00%, the repeatability RSD was 2.40%, and the recovery rate was 94.25%-111.19%, and the content of tea polysaccharide was 54.76 mg/g. Conclusion Phenol-sulfuric acid method is suitable for the determination of tea polysaccharide in tea with DES as extraction solvent.

Objective To elucidate the influence of pH treatment on the structural and functional properties of Solanum tuberosum L. protein. Methods Solanum tuberosum L. protein was selected as the research subject, and the effects of pH on its physical and chemical properties, structure, and conformation were analyzed by fluorescence spectroscopy, Fourier transform infrared spectroscopy, particle size and potential analysis, and scanning electron microscopy. Results Significant differences were observed in the protein subunit composition, particle size distribution, and potential values following treatments at different pH levels. Compared to pH 7, pH 10 enhanced the electrostatic repulsion of Solanum tuberosum L. proteins, significantly increasing protein solubility and viscosity to 89.2% and 19625.0 mPa·s, respectively. Additionally, λ_max in the endogenous fluorescence spectra of the proteins shifted to 343 nm, exposing more hydrophobic groups. The particle size of protein molecules decreased to 123.2 nm, while the absolute value of the Zeta potential increased to 41.3 mV. Protein molecules formed intramolecular disulfide bonds, leading to an increase in the denaturation temperature to 82.22 ℃. At pH 2, the protein aggregated and formed soluble aggregates while unfolding. However, viscosity decreased to 1860.6 mPa·s, λ_max in the fluorescence spectrum shifted to 341 nm, particle size increased to 369.3 nm, the absolute value of the Zeta potential decreased to 8.97 mV, and the number of disulfide bonds did not change significantly. This resulted in insufficient stability of Solanum tuberosum L. protein under acidic conditions, with a tendency for aggregation. Conclusion Different pH treatments can enhance the physicochemical properties of Solanum tuberosum L. protein, and this study aims to offer scientific guidance for its application in food processing.

Objective To establish a method based on real-time fluorescent polymerase chain reaction (PCR) for the identification of the genus Cipangopaludina and Bellamya, and identify the snail-derived ingredients in the meat soup package of river snail rice noodle. Methods Specific primers and probes were designed using mitochondrial genes from the genera Cipangopaludina and Bellamya, respectively. The effectiveness of the established real-time fluorescence PCR method was evaluated for its specificity, sensitivity and repeatability. Results The real-time fluorescence PCR identification method developed in our study exhibited strong specificity, detecting fluorescence signals only in the designated channel for the DNA of the Cipangopaludina and Bellamya, with typical amplification curves observed. No fluorescence signals were detected in the designated channel for the genomic DNA of various heterogeneous animals and plants, including aquatic products, poultry, livestock, and spice and seasoning raw materials, with no observable amplification curves. The method demonstrated sensitivity as low as 0.002 ng/μL for Cipangopaludina and 0.001 ng/μL for Bellamya. The method was employed to analyze DNA extracted from snail meat soup packets in 21 batches of prepackaged river snail rice noodle across various brands in supermarket distribution. In 7 batches of prepackaged river snail rice noodle from different brands, Cipangopaludina components were detected in the DNA of the snail meat soup packets, representing 33.3%. In 18 batches of prepackaged river snail rice noodle from different brands, Bellamya components were detected in the DNA of the snail meat soup packets, representing 85.7%. In 3 batches of prepackaged river snail rice noodle from different brands, neither Cipangopaludina and Bellamya components were detected in the DNA of the snail meat soup packets, accounting for 14.3%. In 7 batches of prepackaged river snail rice noodle from different brands, both Cipangopaludina and Bellamya components were detected in the DNA of the snail meat soup packets, representing 33.3%. Conclusion This method boasts strong specificity and high sensitivity, effectively identifying snail-derived components in snail meat soup packets of river snail rice noodle, thereby providing robust technical support for market regulation.

Objective To investigate the type and drug resistance characteristics and virulence gene carrying of some food-borne methicillin-resistant Staphylococcus aureu (MRSA) in Ningxia. Methods MRSA isolates from some food risk monitoring in Ningxia were collected and subjected to drug susceptibility testing, pulsed-field gel electrophoresis (PFGE), and whole-genome sequencing analysis respectively. Results PFGE typing of 9 food-borne MRSA strains was divided into 3 clusters and 8 kinds of types, all of which were more than 85% provenance. ST typing of the whole genome sequencing results was divided into 4 kinds of ST types, 6 strains were ST59, and the other 3 strains were ST3355, ST7 and ST965, respectively. MRSA were all multi-drug resistant, which carrying different resistance genes and virulence genes, resulting in different drug resistance phenotypes. Conclusion Foodborne MRSA isolates have a large number of genes related to antibiotic resistance and pathogenicity, which pose a significant threat to human health. Therefore, it is of great importance to continuously monitor and take effective measures to reduce the contamination level of MRSA in food to ensure food safety.

Objective To establish a method for the determination of ethylenediaminetetraacetic acid ferric sodium salt (NaFeEDTA) by microemulsion liquid chromatography. Methods After simple dilution and centrifugation of the sample, it could be filtered through a 0.22 μm microporous membrane and directly loaded onto a Waters BEH C₁₈ column (2.1 mm×150 mm, 1.7 µm) was the chromatographic column. The microemulsion mobile phase was 3.64 g/L cetyltrimethylammonium bromide-50 g/L acetonitrile-8 g/L ethyl acetate-6.8 g/L potassium dihydrogen phosphate. The flow rate was 0.30 mL/min and the detection wavelength was 254 nm. The column temperature was 30 ℃ temperature. External standard method was used for quantitative determination. Results Under the selected experimental conditions, the mass concentration of NaFeEDTA had a good linear relationship (r≥0.999) within the range of 0.50-35.00 µg/mL, the limits of detection were 50 mg/kg. The recovery rates of NaFeEDTA were investigated, with average recovery rates ranging from 92.7% to 97.7%. Conclusion This method is easy to operate and has good reproducibility. The method can be used for the detection of NaFeEDTA content in soy sauce.

Objective To establish a method for the determination of 2-hexylpyridine content in the milk and dairy product by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Methods The sample was extracted by acetonitrile vortex extraction, and the analytical solution was purified by QuEChERS dSPE EMR Lipid degreasing tube. After centrifugation, it was tested on a membrane machine. The acetonitrile primary water as the mobile phase was used, the flow rate was set at 0.25 mL/min, the gradient elution procedure was applied, the GL Sciences InertSustain C₁₈ chromatographic column was used for separation, the electro spray positive ion (ESI⁺) mode, the multiple reaction monitoring (MRM) mode was used for detection, and the matrix matching external standard method was used for quantification. Results The methodological validation indicators were well that the calibration curves were linear in the range of 0.5-20.0 ng/mL with the correlation coefficients (r²) larger than 0.998. The average recoveries of 2-hexylpyridine were 94.45%-109.63% and the relative standard deviations were 3.93%-9.53% at 0.005, 0.010 and 0.050 mg/kg with 3 kinds of spiked levels. Conclusion The accuracy, precision, and sensitivity of the method meet the requirements for residue detection.

Objective To establish a simple and efficient method for the determination of 6 kinds of eugenols in infant formula milk powder by gas chromatography-mass spectrometry. Methods After ultrasonic extraction with acetonitrile, the sample was purified and degreased using acetonitrile saturated n-hexane. The n-hexane was discarded, and acetonitrile was extracted and concentrated to a volume of 1 mL. DB-1701 chromatographic column was used to separate without splitting the sample, with an injection volume of 1 μL. Ion monitoring mode for gas chromatography-mass spectrometry determination and external standard method for quantification was used. Results The 6 kinds of eugenols showed a good linear relationship within the range of 20-500 ng/mL, the limit of detection of the 6 kinds of eugenol compounds in this method was 0.007 mg/kg, and the limit of quantitation was 0.02 mg/kg. In 2 matrix samples of milk powder and sheep milk powder, the average recoveries of 6 kinds of eugenols at 3 different concentration levels were between 97.3% and 105.0%, the relative standard deviation (RSD) was between 0.3% and 3.7%. Conclusion The pretreatment operation of this method is simple and fast, and the detection method has high sensitivity and good stability, meeting the requirements of national standards, in order to provide reference basis for establishing national standards or methods for the detection of 6 kinds of eugenols in infant formula milk powder.

Benzotriazole ultraviolet absorbers (BUVs) are a new class of persistent organic pollutants, which are widely used as light stabilizers in various industrial products with good ultraviolet absorbing ability and thermal stability, among which 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV-328) has been listed in the Stockholm Convention. Currently, there are a large number of domestic and international studies on the exposure of BUVs in the environment and living organisms, and the concentration of BUVs in sediments and soils generally reaches hundreds of ng/g, and they are frequently detected in water bodies and fish. Humans have an exposure risk through dietary intake and respiratory tract intake, but there are few reports on the load of BUVs in human urine and blood, and it is noteworthy that the load of BUVs in human breast milk can reach up to thousands of ng/g. In view of the bioaccumulation and potential toxicity of BUVs, this paper provided a detailed overview of the exposure to BUVs in various types of environmental, biological, and human tissue samples. This paper briefly summarized the potential hazards of BUVs, such as liver and kidney target organ toxicity, endocrine disrupting effects, and immunotoxicity and neurotoxicity, aiming to provide a reference for the assessment of the health risk of BUVs in human beings.

Objective To investigate the epidemiological characteristics and drug resistance of foodborne disease cases and pathogens in Jinshan District of Shanghai. Methods The case information of foodborne diseases in 15 sentinel medical institutions in Jinshan District was monitored in 2023, and the positive bacteria in the stool samples of patients were rechecked, identified, and tested for drug sensitivity. Results In 2023, a total of 408 cases of foodborne diseases were reported in Jinshan District, the male to female ratio was 5:4, most of them were 18-34 years old, the occupation was mainly workers, migrant workers and farmers, and the incidence was high from May to September. Except for multiple and mixed foods, vegetables and fruits accounted for a relatively high proportion in suspicious exposed foods. The detection rate of pathogenic bacteria was 21.46% (47/219), diarrheagenic Escherichia coli was the main pathogen, and norovirus was 18.72% (41/219). The results of drug sensitivity showed that the proportion of multi-drug resistant strains in Salmonella was 83.33% (10/12). Conclusion In the 2023 foodborne disease surveillance in Jinshan District, norovirus and diarrheagenic Escherichia coli are the main pathogenic agents. Among the pathogenic bacteria, both Salmonella and diarrheagenic Escherichia coli shows varying degrees of drug resistance. It is necessary to continue strengthening the monitoring of foodborne diseases. Meanwhile, relevant departments shall enhance public awareness of antibiotic resistance, and strengthen the management, rational use and sensitivity testing of various antibiotics.