Objective To evaluate the antimicrobial resistance of bacteria in food animal in Quzhou City, Zhejiang Province from 2022 to 2023. Methods In the past two years, 690 swab samples from 40 livestock and poultry farms were randomly collected, and Escherichia coli and Enterococci were separated using selective culture medium. They were then identified by polymerase chain reaction and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The minimum inhibitory concentration (MIC) of different antibiotics against these two bacteria was determined using broth microdilution method. Results In 2022, the highest antimicrobial resistance rate of Escherichia coli isolated from swab samples to tetracycline was 87.2%, with sulfamethoxazole following at 81.1%. One strain was resistant to meropenem and 5 strains were resistant to colistin. In 2023, the antimicrobial resistance rates of Escherichia coli isolated from swab samples to spectinomycin, florfenicol, trimethoprim/sulfamethoxazole, ceftiofur, and ofloxacin were all lower than those in 2022, and the antimicrobial resistance rates to meropenem and colistin were both 0%. The resistance rates of Enterococci isolated from swab samples to erythromycin, clindamycin, ofloxacin, cefotaxime, sulfamethoxazole, and tiamulin were all lower in 2023 than in 2022, while the resistance rates to penicillin, tetracycline, and linezolid were higher. No vancomycin-resistant enterococci were detected in either year. From the analysis of the antimicrobial resistance rates, MIC distribution, and antimicrobial susceptibility profiles of Escherichia coli and Enterococci over the two years, it could be concluded that both bacteria demonstrated decreased resistance to most antibiotics, with Escherichia coli showing a more significant reduction. Conclusion In 2023, the overall resistance level of Escherichia coli and enterococci of food-animal origin in the Quzhou Area has declined significantly compared to 2022. However, multi-drug resistance still exists and the spectrum of resistance is rather broad, posing a threat to food safety and human health.

Objective To study the effects of ultraviolet pre-sterilization on the quality of fresh pork. Methods Different packaging conditions (bare packaging and fresh-keeping bag packaging), irradiation distance (6, 9 and 12 cm) and irradiation time [bare packaging (3, 5, 10 s), fresh-keeping bag packaging (6, 10, 14 s)] were set in this study. The feasibility of ultraviolet treatment to reduce the number of pork microorganisms and prolong the shelf life of pork was explored by measuring the total number of colonies, sensory evaluation, color difference, total volatile basic nitrogen (TVB-N) and thiobarbituric acid reactive substances (TBARS). Results The results showed that the best ultraviolet irradiation conditions for naked packaged fresh pork were 9 cm-10 s, and the best ultraviolet irradiation conditions for fresh-keeping bag packaged pork were 6 cm-14 s, which could reduce the initial microbial number of fresh pork by 0.44 logCFU/g and 0.61 logCFU/g, respectively, but had no significant effect on fat oxidation, sensory evaluation and color. Conclusion The ultraviolet pre-sterilization treatment can reduce the initial number of microorganisms in pork, slow down the increase of TVB-N value and lipid oxidation, and has no significant effect on the sensory quality and color of fresh meat. The shelf life of pork is prolonged by 3-4 d, which has potential application value in the field of pork preservation.

Objective To explore the browning prevention effects of radio frequency and heat shock treatment on honey peach during frozen storage. Methods Heat shock and radio frequency with different durations were used for pretreatment, and the changes in browning and quality were monitored over a 7 days frozen storage period. Results Compared with heat shock treatment, radio frequency treatment showed a smaller impact on the TSS/TA and pH of the peaches, and significantly reduced electrical conductivity (P<0.05), indicating that it could be better maintain the integrity of the peach cell membrane by radio frequency pretreatment. Based on the studies of key enzymes, substrates, and products related to browning, it showed a good inhibitory effect of radio frequency treatment on the activity of polyphenol oxidase, soluble quinones, and total phenols in frozen peaches, and which had a certain effect on maintaining catalase activity. This could reduce the degree of fruit browning and better resist the damage of reactive oxygen species to the peach fruit. A slight increase in malondialdehyde content was observed under higher temperature of radio frequency treatment, but there was no significant difference (P>0.05). Conclusion Radio frequency treatment has a good inhibitory effect on peach browning and can better maintain the physicochemical quality of the peaches.

Objective To investigate the inhibitory effects of tuna skin collagen oligo-peptide (TSCP) on melanin production and oxidative damage protection in Hacat cells. Methods Through investigated the effects of TSCP on melanin and tyrosinase production in B16-f10 cells, analyzed the antioxidant activity in B16-f10 cells, and assessed its protective effect against hydrogen peroxide (H₂O₂) induced oxidative damage in Hacat cells, the inhibitory mechanism of TSCP on melanin production and its protective mechanism against oxidative damage in Hacat cells were revealed. Results The experimental results showed that TSCP exhibits no significant cytotoxicity to B16-f10 cells at concentrations ranging from 0.01 to 1.00 mg/mL, and significantly inhibited tyrosinase activity and melanin production. At a concentration of 1.00 mg/mL, TSCP significantly reduced melanin content to 83.79%±4.31% (P<0.01) and tyrosinase activity to 78.14%±6.95% (P<0.001). TSCP also significantly reduced the levels of reactive oxygen species (ROS) in B16-f10 cells. At 1.00 mg/mL, the ROS levels decreased to 53.5%±4.4% of the control group (P<0.001), indicating potent antioxidant potential. Additionally, TSCP increased the activity of superoxide dismutase (SOD) to (16.62±0.62) U/mg prot (P<0.001) and reduced malondialdehyde (MDA) content to (0.352±0.051) U/mg prot (P<0.001). Glutathione peroxidase (GSH-Px) levels were also elevated, reaching (284.55±4.99) ng/mL at 1.0 mg/mL (P<0.01). In the Hacat cell model, TSCP similarly exhibited no significant toxicity and, in the H₂O₂-induced oxidative damage model, significantly improved cell viability and suppressed apoptosis. At 1.00 mg/mL, TSCP improved cell survival to 73.66%±5.48% (P<0.01), compared to the model group. Conclusion TSCP can inhibit melanin production, reduce oxidative stress, providing a foundation for its potential applications in skin whitening and antioxidant therapies.

Objective To explore the effects of nine steaming and nine processing methods on the characteristics, microstructure, and effective components of Polygonatum sibiricum, and provide relevant basis for the processing technology of Polygonatum sibiricum. Methods Jiuhuangjing was prepared using the nine steaming and nine preparation method, and its characteristics, microstructure, and active ingredients were evaluated as quality control indicators for evaluation. Results After six steaming and six processing, the appearance of Polygonatum sibiricum basically meets the requirements of the Chinese pharmacopoeia. The surface of Polygonatum sibiricum after nine steaming and nine processing was black, oily, and smooth, with a uniform and glossy color. The interior was black with red inside and black inside, with a honeycomb like structure. The structure of calcium oxalate was broken, the content of polysaccharides and the water-soluble components were reduced, and the alcohol soluble components were increased. This suggested that after nine steaming and nine processing, the irritants of Polygonatum sibiricum gradually decrease, the polysaccharides undergo hydrolysis, and gradually decompose into monosaccharides, and the taste changes from sour to sweet without a tingling sensation. Conclusion This experiment establishes a scoring standard for the characteristics of nine steamed and nine processed Polygonatum sibiricum, in order to provide a basis for the quality identification and construction of quality standards for nine steamed and nine processed Polygonatum sibiricum.

Fermented vegetables are considered one of the most nutritious and beneficial foods for health. The research in the microbial community structure is a great significance to explore the dominant strain resources and improve the flavor quality of fermented vegetables. This paper summarized the application of the next-generation sequencing technology on microbial community of fermented vegetables. Some analysis methods were emphatically introduced involving with microbial community succession, Alpha diversity analysis, Beta diversity analysis, functional annotation (Kyoto Encyclopedia of Genes and Genomes metabolic pathway annotation, cluster of orthologous group annotation, gene ontology annotation), network and correlation analysis of environmental factors. Based on the research progress, this paper suggests implement combined application among the next-generation sequencing technology and multiple omics technology including transcriptomics, proteomics, metabolomics. The correlation between microbial function with color, flavor and texture of fermented vegetables should be investigated. The new strain resources with fermenting high-quality vegetables should be screened and obtained. It provides a theoretical basis for the transformation of traditional fermented vegetables to standardization, industrialization and modernization in China.

Objective To construct a method for rapid detection of chromium (VI) in drinking water on a paper-based microfluidic chip. Methods The paper chips were manufactured by directly drawing on filter paper with a modified gel pen filled with alkylketene dimmer solution and then dried. The chromium (VI) was detected on the paper chips. Parameters influencing the chromium (VI) determination were investigated, including concentration of sulfuric acid solution and diphenyl carbamide solution, reaction time, and temperature. Results In this study, the linear range of chromium detection was 0~0.20 mg/L, the detection limit was 0.0036 mg/L, and the recovery rate was 97.7%~109.0%. It had wide linear range, high sensitivity and good repeatability. Conclusion The method has the advantages of simple operation and the accurate detection result, does not require expensive and complex large instruments, and has adaptability to simultaneous detection of multiple samples and on-site real-time detection.

Objective To establish subsequently the real-time quantitative polymerase chain reaction (PCR) method that could quickly and accurately identify Cronobacter sakazakii, and design specific primer probes based on the DNA gyrB subunit gene. Methods The target gene sequences were searched and downloaded from National Center for Biotechnology Information (NCBI), sequence comparison was performed using DNAMAN, and primer probes were designed by Primer Express software. This established real-time quantitative PCR method was validated through specificity tests, absolute sensitivity tests, relative sensitivity tests and anti-interference tests. The 40 common pathogenic bacteria standard strains were selected for specificity validation. Results The results of multi-dimensional specificity validation showed that the method was able to specifically detect Cronobacter sakazakii, and there was no non-specific amplification for other closely related Cronobacter and common pathogenic bacteria in food. DNA detection sensitivity was 0.0100 ng/μL, while relative sensitivity was 10³ CFU/mL. The anti-interference experiment results showed that mixing interfering bacteria and their DNA with Cronobacter sakazakii DNA and Cronobacter sakazakii did not significantly affect the detection results, indicating that this method had good anti-interference ability. Conclusion The primer probes designed in this study are specific, rapid, sensitive and anti-interference for the detection of Cronobacter sakazakii in food samples under real-time fluorescence PCR method. It can provide technical support for detection of Cronobacter sakazakii in the future.

Objective To compare the changes in muscle nutritional components and quality indicators of Trionyx sinensis at different stages of ecological purification breeding. Methods Nutritional parameters such as morphological index and protein, fat, amino acid and fatty acid in muscle and skirt were measured during the 0th, 15th and 30th d of purification, and the nutritional and quality changes of Trionyx sinensis were compared with the textural and structural characteristics. Results With the extension of ecological purification breeding time, the crude fat of Trionyx sinensis showed a trend of rapid decline followed by a slight increase, while the crude protein showed a trend of initial increase followed by a decrease. The total amino acid content showed a decreasing trend. In the entire ecological purification breeding process, there were significant changesin the crude protein and crude fat content in the muscles of Trionyx sinensis (P<0.05), as well as in the moisture and ash content of their skirts. There were significant differences in the content of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids before and after purification (P<0.05), and the content of saturated fatty acids and polyunsaturated fatty acids increased at 15 days. Except for valine and proline, all other amino acids decreased, and there was a significant decrease in cysteine, lysine, glutamate, histidine, aspartic acid, glycine, and alanine in the purified muscles after 30 days compared to the untreated ones (P<0.05). In the whole texture mode, the hardness, adhesion and mastication of the muscle of Trionyx sinensis purified for 15 days were significantly improved (P<0.05) compared with that of the muscle before purification. Conclusion Compared with traditional pond aquaculture of Trionyx sinensis, the crude protein content, essential amino acids, and total umami amino acids are significantly increased, and the optimal purification time is 15 d. Ecological purification breeding can improve the quality of Trionyx sinensis and better meet the needs of consumers. It is a purification breeding method worth applying in production practice, which is conducive to increasing the supply of high-quality and cost-effective Trionyx sinensis and providing research data for improving the quality of high-quality aquatic products.

Objective To establish a method for simultaneous determination of 317 kinds of pesticide residues in pomelo flowers by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) coupled with QuEChERS extraction. Methods Pomelo flowers samples were extracted with acetonitrile and salted with extraction salt pack, cleaned up by ethylenediamine-N-propylsilane silica gel (PSA) and graphitized carbon blank (GCB), the analytes were separated on an ACQUITY UPLC HSS T3 column to achieve the separation within 30 min. The 317 kinds of pesticides were detected in electron spray ionization with positive ion mode and electron spray ionization with negative ion mode with multiple reaction monitoring (MRM) mode and quantified by matrix matching curve external standard method. Results The 317 kinds of pesticides in pomelo flowers showed good linearity with correlation coefficients (r) greater than 0.995 within the range of 2.0-200.0 µg/L, and the limits of quantification were 0.002-0.010 mg/kg, the average recoveries at 3 spiked levels were 74.3%-120.3%, and the relative standard deviations were 0.36%-10.00%. Conclusion The method is simple, rapid, accurate and sensitive, can meet the rapid detection requirements of 317 kinds of pesticides in pomelo flowers and provide reliable data support for further standardizing for edible safety evaluation of pomelo flowers.