Objective To establish a method for the determination of migration of isosorbide in isosorbide modified polyethylene terephthalate (PET) products by gas chromatography-flame ionization detector (GC-FID). Methods The effects of different chromatographic conditions on the separation of isosorbide were investigated. HP-5 was selected as the separation column and 260 ℃ was selected as the injection port temperature. The effects of different pretreatment methods on the extraction of isosorbide from food simulants were investigated. The olive oil food simulant was extracted with methanol, purified with n-hexane and filtered before analyzed. The 95% ethanol and isooctane simulants were directly analyzed by the machine after filtered. Other food simulants were diluted with methanol and then directly analyzed by the machine. The external standard method was used for quantification. Results Isosorbide had a good linear relationship in the range of 2.5-40.0 mg/L (aqueous food simulants), 0.6-10.0 mg/L (substitute simulants) and 1.5-25.0 mg/kg (fatty food simulants), and the correlation coefficient was above 0.995. The limit of detection of this method for the migration of isosorbide was 0.8 mg/kg (aqueous food simulants), 0.2 mg/kg (substitute simulants) and 0.5 mg/kg (fatty food simulants). The limit of quantification was 2.5 mg/kg (aqueous food simulants), 0.6 mg/kg (substitute simulants) and 1.5 mg/kg (fatty food simulants). The spiked recoveries were 92.0%-112.3%, and the relative standard deviation was 0.2%-4.3% (n=6). Conclusions This method has good linearity, high precision, sensitivity and accuracy, and can meet the detection requirements of isosorbide migration in modified PET products.

Objective To study the effects of methyl-β-cyclodextrin (M-β-CD) on removing cholesterol from fish oil. Methods Cholesterol removal rate and fish oil recovery rate were used as key indicators to screen suitable materials for removing cholesterol from fish oil from β-cyclodextrin (β-CD) and its derivatives. The optimal cholesterol removal process conditions were determined through orthogonal experiments, and the quality of fish oil before and after cholesterol removal was compared. Results M-β-CD was the best material for removing cholesterol from fish oil. The optimal process conditions of M-β-CD removal of cholesterol in fish oil were as follows: M-β-CD dosage of 30%, temperature of 50 ℃, time of 15 min. The cholesterol removal rate was 51.34%, and the fish oil recovery rate was 84.84% under these conditions. When cholesterol was removed under the optimal process conditions, the acid value, peroxide value, and anisidine value of fish oil significantly decreased (P<0.05), while the iodine value did not change significantly (P>0.05). The content of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) significantly increased (P<0.05), the proportions of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA) were 31.33%, 16.81%, and 51.86% of the total lipid content, respectively, with no significant changes observed among them (P>0.05). Conclusion The treatment of fish oil with M-β-CD not only efficiently removes cholesterol but also enhances the quality, making it a promising method for cholesterol removal from fish oil.

Objective To compare three domestic and foreign Cronobacter detection methods, for verifying the actual detection performance of three standard methods: GB 4789.40—2016 National standard for food safety food-Microbiology tests Cronobacter spp. (Enterobacter sakazakii) test, GB 4789.40—2024 National standard for food safety food-Microbiology tests Cronobacter test and ISO 22964—2017 Food chain microbiology-Horizontal detection methods for Cronobacter spp. Methods Three standard methods were used to detect Cronobacter in 403 samples collected from 2020 to 2022, including infant formula, cereal-based infant supplements, corn ingredients, and raw and supplemental ingredients of infant formula, and to test Cronobacter isolates for drug susceptibility. Results The total contamination rate of Cronobacter in 403 samples was 17.9% (72/403), and the contamination rates of corn raw material, cereal-based infant supplement and infant formula were 37.3% (38/102), 23.4% (33/141) and 1.0% (1/100), respectively. Although there was no significant difference in the total detection rate among the three standard methods (χ²=3.601, P=0.170), 41.5 ℃ could effectively improve the detection rate compared with 44 ℃ (χ²=18.813, P=0.000). The resistance rate of 72 strains of Cronobacter was 55.6% (40/72), among which the resistance rates of cefazolin, ampicillin, and amoxicillin/clavulanic acid were 52.8% (38/72), 5.6% (4/72), and 1.4% (1/72), respectively. Conclusion This study shows that GB 4789.40—2024 has reached the level of the international relevant methods, providing data support for the mutual recognition of the test results of GB 4789.40 and ISO 22964 methods. Cronobacter has high resistance to cefazolin, which should be avoided when choosing antibiotics for clinical treatment.

Objective To investigate the drug resistance, biofilm formation ability, and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) isolated from food and clinical samples. Methods A total of 21 MRSA strains isolated from commercial food and 30 MRSA strains isolated from clinical cases in a Class 3 Grade A hospital in Shaanxi from 2019 to 2020 were tested for drug susceptibility, MLST, spa, SCCmec typing, and biofilm formation ability. The phylogenetic analysis of strains from different sources was performed based on SNP by whole genome sequencing. Results The resistance rates of 51 MRSA strains to penicillin, oxacillin, erythromycin, clindamycin, tetracycline, and other antibiotics exceeded 50%. Penicillin and oxacillin exhibited the highest resistance rates (100%), followed by erythromycin, clindamycin, and tetracycline with resistance rates of 98.04%, 96.08%, and 52.94% respectively. The ST59-t437-IVa(2B) molecular type was predominant among 21 food MRSA strains and 30 clinical MRSA strains, accounting for 52.38% (11/21) and 36.67% (11/30), respectively. Among the 21 food-borne MRSA strains, 38.09% (8/21) exhibited the capacity for biofilm formation, while all 30 clinical MRSA strains demonstrated biofilm-forming ability. The phylogenetic analysis revealed that ST59-t437-IVa(2B) constituted the primary evolutionary lineage of MRSA strains isolated from both food and clinical samples, with some strains from these two sources falling within the same evolutionary branch. Conclusion The drug-resistant types and rates of drug resistance in MRSA strains isolated from both food and clinical sources exhibited a high degree of consistency in this study. Moreover, the biofilm formation ability was found to be stronger in clinical MRSA isolates compared to those derived from food-borne sources. Additionally, close genetic relationships were observed between certain MRSA strains obtained from both food and clinical samples, highlighting the significance of further research and attention towards the risk posed by food-borne MRSA.

Objective To delve into the influences of slightly acidic electrolyzed water (SAEW) and ultra-high pressure (UHP) on the bactericidal potency of Panax notoginseng tubers, and quantification of synergistic bactericidal effect, constructing bactericidal model. Methods Fresh Panax notoginseng was selected as the raw material, with independent variables encompassing SAEW available chlorine concentrations (25, 30, 35 mg/L), solid-liquid ratios (1:20, 1:30, 1:40 g/mL), treatment durations (4, 6, 8 min), and pressures (200, 300, 400 MPa). The number of deceased Escherichia coli on the surface of Panax notoginseng tubers was set as the response value. A response surface methodology was adopted to optimize these treatment parameters and establish a coordination range for parallel SAEW-UHP treatments while quantifying their synergistic effects, verified the prediction accuracy of the model. Results Revealed that based on single-factor experiments, SAEW-UHP parallel technology was better than single technology in bactericidal effect, the optimal sterilization process parameters for the SAEW-UHP parallel technology lie within a solid-liquid ratio range of 1:26.90-1:33.34 g/mL, available chlorine concentrations range of 29.03-35.00 mg/L, treatment durations range of 5.27-6.83 min, pressure range of 295.57-400.00 MPa and the material-to-liquid ratio was set at 1:31.28 g/mL, with an electrolyzed water concentration was set at 34.25 mg/L, treatment duration was set at 6.79 min, and the pressure was set at 400.00 MPa, the synergistic effect predicted by the model reached its maximum, yielding a peak quantification value of 1.87 lg(CFU/mL). Conclusion This research quantitatively elucidates the augmented sterilization efficacy conferred by the SAEW-UHP parallel technology, utilized the smallest dosage and the lowest processing intensity to achieve the best bactericidal effect, which furnishing a theoretical underpinning for fresh produce storage strategies, offering novel approaches to green processing, and providing a guarantee for food microbial safety.

Objective To Establish a method for simultaneous determination of 11 kinds of caine anesthetics and their 3 kinds of metabolites in aquatic products by QuEChERS-liquid chromatography-tandem mass spectrometry. Methods The samples were extracted by acetonitrile, dehydrated by anhydrous MgSO₄ and NaCl, purified by 100 mg primary secondary amine (PSA), filtered by 0.22 µm organic microporous membrane, and qualitatively and quantitatively determined by liquid chromatography-tandem mass spectrometry. Results The 11 kinds of caine anesthetes and their 3 kinds of metabolites showed a good linear relationship in the mass concentration range of 0.01-5.00 μg/L, and the correlation coefficients (r) were 0.99529-0.99989. The limit of detection (LOD) and the limit of quantification (LOQ) of 11 kinds of caine anesthetics and their 3 kinds of metabolites were 0.05-2.00 µg/kg and 0.15-5.00 µg/kg, respectively. The 3 kinds of substrates, white shrimp, carp and turbinus were performed at 3 levels: 1 times LOQ, 2-2.5 times LOQ and 10 times LOQ. The recoveries of 11 kinds of caine anesthetics and their 3 kinds of metabolites in 3 samples were 71.3%-114.2%, 71.2%-107.0% and 70.4%-104.5%, and the relative standard deviations were 0.7%-11.2%, 0.5%-11.5% and 0.8%-14.2%. The method was used to detect 50 batches of different varieties of aquatic products in the market. The results showed that 4 batches of products were detected with caine anesthetic, and the other 46 batches were not detected, the detection rate was 8%. The detected items were mainly tricaine, benzocaine, m-aminobenzoic acid and p-aminobenzoic acid, the content of which were 5.68-90.80 μg/kg, and the other 10 kinds of compounds were not detected. Conclusions The method is simple and fast, has high sensitivity, accuracy and precision, and can simultaneously determine a variety of caine anesthetics in aquatic products. It is suitable for the determination of batch samples, and has high practical application significance, and can provide powerful technical support for food safety monitoring.

Objective To explore the genes that respond to the synthesis pathway of norovirus binding receptors in Crassostrea gigas under different temperature stress, screen them, and study their cloning and expression patterns. Methods Crassostrea gigas were treated at high temperature (25 ℃) and low temperature (5 ℃), and two tissues of gills and digestive glands were extracted for RNA extracted for transcriptome sequencing and analysis. Selected genes on the synthesis pathway of norovirus binding receptors that responded to temperature treatment as targets, clone, express in prokaryotic cells, and identified by Western blotting. The tissue expression and seasonal expression pattern of the gene were analyzed by quantitative real time-polymerase chain reaction (qRT-PCR). Results The β1,3 galactosyltransferase-like 1 (B3GALT1-like) gene (GenBank LOC117683256) was significantly upregulated in multiple sampling sites in the gill group. The 1089 bp coding sequence (CDS) region of the gene was amplified. After 8 h of induction of 25 ℃, isopropyl beta-D-1-thiogalactopyranoside (IPTG), a protein band of about 84.9 kDa appeared, which was specifically bound to both anti-MBP tag antibody and anti-human B3GALT1 antibody. B3GALT1-like genes was abundantly expressed in gill tissue and was significantly higher at low temperature than at high temperature (P<0.01). Conclusion The expression level of B3GALT1 gene in Crassostrea gigas is affected by temperature, and the expressed protein has similar immunogenicity to human β1,3 galactosyltransferase. The tissue expression and seasonal expression patterns of the B3GALT1 gene are somewhat consistent with the seasonality of norovirus outbreaks. This study provides a foundation for further exploration of the molecular mechanism of seasonal enrichment of norovirus in Crassostrea gigas.

Food origin traceability technology is an important technical means for the effective implementation of food origin traceability and the protection of regional brands and specialty products. China has established a number of food safety standard systems, including “geographical indications of Chinese agricultural products”. There is an increasing demand for food origin discrimination at home and abroad, and the characteristics of volatile organic compounds (VOCs) are closely related to food origin, which can be used to characterize the differences between different products of the same kind of food. Gas chromatography-ion mobility spectrometry (GC-IMS) technology is a new technology developed in recent years for the determination of VOCs, which has the advantages of good separation effect, fast detection speed and high sensitivity, and has the potential to become an effective technical means for origin tracing. This paper introduced the working principle and characteristics of GC-IMS technology, summarized the progress of the application of GC-IMS technology in the origin traceability of animal and plant-derived foods in recent years, and discussed the future development direction of GC-IMS technology, in order to provide technical reference for the continuous expansion of the application of GC-IMS technology in the origin traceability of food.

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 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.