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.

Objective To establish a method for the determination of the migration of 9,9-bis(methoxymethyl)fluorene in plastic food contact materials and articles by gas chromatography-mass spectrometry. Methods The water-based food simulants were extracted by n-hexane, and the chemical alternative solvents (95% ethanol and isooctane) were directly injected, and the olive oil simulants were extracted with acetonitrile and then injected, and the samples were analyzed by gas chromatography-tandem mass spectrometry and quantified by external standard method. Results A method for the determination of 9,9-bis(methoxymethyl)fluorene in plastic food contact materials was established. The limit of detection was 0.01 mg/kg or mg/L, the limit of quantification was 0.03 mg/kg or mg/L, the recovery rates were 80.0%-110.0%, and the relative standard deviations were 1.2%-6.0% (n=6). The actual samples of 10 kinds of polypropylene (PP) food contact materials were determined by this method, and the detection rate was 10%, and the detection concentration was 0.12 mg/kg. Conclusion The method is sensitive, has high recovery and accuracy, and the limit of detection can meet the requirements of regulations, and can be used for the practical testing of the migration of 9,9-bis(methoxymethyl)fluorene in polypropylene (PP) food contact materials.

Objective To establish and optimize a method for the determination of perchlorate (ClO₄^-) migration in food contact plastic products by large volume injection-ion chromatography (IC). Methods Water, 3% acetic acid (m:V), 4% acetic acid (V:V), 10% ethanol (V:V), 20% ethanol (V:V), 50% ethanol (V:V), and 95% ethanol (V:V) were selected as food simulants, and the isocratic elution was performed with a mixture of 14 mmol/L anhydrous sodium carbonate and 20% acetonitrile (volume fraction) as mobile phases, with an injection volume of 800 μL and a flow rate of 1.0 mL/min. The separation was performed on a Metrosep A Supp 4 ion chromatography column (250 mm× 4.0 mm, 9.0 μm) and a Metrosep A Supp RP Guard guard column (50 mm×4.0 mm, 9.0 μm) at a column temperature of 30 ℃ with a conductivity detector for the determination and the quantification of the extract by the external standard method. Results The method validation results showed that the method was linear with the linear correlation coefficient of the standard working curve greater than 0.995. The limit of detection was 0.15 μg/kg, the limit of quantification was 0.50 μg/kg, and the recoveries were 83.2%~99.1%, and the precision was 2.7%~9.1% (n=6). Conclusion The method is reliable, convenient, sensitive, has good separation effects, and suitable for the determination of perchlorate migration in food contact plastic 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.

Objective To establish an automatic, fast and high-resolution detection method for 5 kinds of common pathogenic bacteria in aquatic products, and improve the efficiency and accuracy of detecting pathogenic microorganisms in aquatic products. Methods Genes of owpW, tlh, invA, femA, and prfA from Vibrio cholera, Vibrio parahaemolyticus, Salmonella, Staphylococcus aureus, and Listeria monocytogenes were amplified by multiple polymerase chain reaction (PCR). PCR products were used as templates for single nucleotide extention and molecular weight of the extended probes was detected on the mass spectrometer. The molecular weight of probes for genes owpW、tlh、invA、femA and prfA were 4848, 5435, 5890, 6560 and 7096 Da. The molecular weights of the extended probes were 5119 Da (plus A), 5697 Da (plus T), 6137 Da (plus C), 6822 Da (plus T) and 7383 Da (plus G), respectively. This finally determined system was verified by reproducibility test, specificity test, sensitivity test and detection test of artificially contaminated aquatic samples. Results Using a sample of mixed DNA from 5 kinds of different bacteria as a template for nucleic acid mass spectrometry detection, the corresponding 5 kinds of probes could be extended simultaneously with an extension efficiency greater than 80%. The above 5 kinds of bacteria would not be detected in samples using interfering bacteria as templates. The sensitivity for detecting Salmonella, Staphylococcus aureus, Listeria monocytogenes, Vibrio parahaemolyticus, and Vibrio cholerae could reach 150, 350, 160, 130, and 180 CFU/mL, respectively. Conclusion This method demonstrates good reproducibility, specificity, and sensitivity, and has a high degree of automation, which can meet the detection needs of the above 5 kinds of microorganisms in aquatic products simultaneously.

Objective To establish a method for the determination of 15 kinds of chemicals illegally added in prefabricated food by ultra performance liquid chromatography-triple quadrupole composite linear ion trap mass spectrometry in multiple reaction monitoring-information dependent acquisition-enhanced product ion (MRM-IDA-EPI) mode combined with pass-through solid phase extraction technology. Methods The samples were extracted with 1% (volume fraction) formic acid in acetonitrile. The extractive solution was purified by pass-through solid phase extraction column Captiva EMR-Lipid, and the purified liquid was separated on a Agilent Poroshell 120 EC-C₁₈ (2.1 mm×100 mm, 1.9 μm) column. The mobile phase was acetonitrile and 5 mmol/L aqueous ammonium acetate containing 0.05% formic acid. The target compounds were detected by MRM-IDA-EPI mode with external standard method. Results The calibration curves of the 15 kinds of compounds were linear in the concentration range within limits with correlation coefficients between 0.9956 and 0.9996. The limits of detection ranged from 0.62-62.50 μg/kg. The average recoveries of 15 kinds of compounds at 3 different levels ranged from 78.33%-109.51% with accuracy of 0.67%-14.02%. Conclusion The method can be applied to the determination of 15 kinds of chemicals illegally added in prefabricated food with its rapidity, high accuracy and high precision, providing support for quality control and market regulation of prefabricated food.

Objective To establish a method for the determination of fluoride ion in tea and tea beverages by activated carbon purification-ion chromatography, and then to study the health risks of tea water and tea beverages. Methods The experiment was carried out by brewing 6 kinds of tea in 2 ways respectively. Method 1: Tea was brewed in a time gradient. Method 2: Add tea once, brew tea with several times and then collect tea. Collect tea by brewing tea with water several times. The tea and tea beverages were purified by activated carbon, filtered by 0.45 μm microporous filter membrane, separated by AS23 ion chromatographic column (4.0 mm×250 mm) with 4.5 mmol/L Na₂CO₃ and 0.8 mmol/L NaHCO₃ solution as leach solution, and tested by ion chromatography. The health risk was assessed by the highest tea fluoride dissolution with method 1, the total tea fluoride dissolution with method 2 and tea fluoride content in tea beverages. Results Under the optimal analysis conditions, the limit of detection of fluoride ions was 0.016 mg/L. In the range of 0.1-5.0 mg/L, the linear relationship was good, the correlation coefficient (r²) was 0.9996, the recovery rates were 94.93%-105.32%, the relative standard deviations were 1.02%-2.13% (n=6). The method detected the amount of fluoride ion dissolved in tea, and found that the dissolution increased continuously with the extension of brewing time and reached the highest value. With the increase of brewing times, the dissolution of fluoride ion in tea increased first, and then the decline trend gradually slowed down. The dissolution rate of fluoride ion in the first 2 brewing times reached more than 65% of total dissolution. Conclusion The method has high sensitivity, good accuracy, simple operation and practical value. Daily intake of tea fluoride in tea and tea beverages obtained from 6 kinds of tea under 2 brewing methods are in line with the daily intake limit of fluoride recommended by China and the World Health Organization. The target hazard quotient (THQ) values are less than 1, and there is no significant health risk to human. It is recommended to reduce tea brewing time, wash tea, and choose high-quality tea to drink tea scientifically and healthily.

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.

Iodine is essential for the synthesis of thyroid hormones in humans, it plays an important role in the prevention and treatment of diseases caused by endemic iodine deficiency disorders and hereditary thyroid dysfunction, eta.. Excessive or deficient iodine intake both have negative effects on human health. Seaweed, as a quality food source rich in iodine, is an ideal natural iodine supplement. With the increasing incidence of thyroid disease, it has led to a rejection of seaweed products with high iodine content, such as Laminaria japonica. A large number of studies show that there is no direct data to suggest that excessive consumption of seaweeds can have adverse effects our body despite the high iodine conten. Therefore, the paper summarized the research progress on morphological distribution of iodine from seaweed, safety evaluation of different forms of iodine, changes of speciation before and after processing, as well as bioavailability of iodine in edible seaweeds. This study provides ideas for evaluating the edible safety of iodine in seaweeds, and also provides scientific evidence for the healthy development of seaweed industry.

Aquatic products, as a significant source of high-quality animal protein, play a crucial role in the fishery economy of China. The aquatic product processing industry not only enhances the prosperity of this sector but also fosters the development of related industries, thereby serving as a vital link in the comprehensive advancement of fisheries. The standard system for aquatic product processing serves as the foundational institution for ensuring the high-quality development of China’s fishery industry. Enhancing the construction of the aquatic product processing system, refining the standard system, and fostering the healthy development of the aquatic product processing industry hold immense significance in safeguarding the quality and safety of aquatic products in China. This paper examined the current status of the standard system for aquatic product processing in China and proposes ideas, principles, and frameworks for its establishment. It was recommended that emphasis be placed on the coordinated development of an integrated industrial chain processing standard system while prioritizing quality evaluation methods for aquatic products. Furthermore, it was essential to expedite the formulation of standards encompassing general applicability, product quality grading and detection methodologies, processing quality control management and traceability protocols, storage and preservation practices, as well as cold chain logistics. These efforts aim to facilitate effective alignment between standards across both upstream and downstream segments of the industrial chain and provide standardized support for fostering sustainable growth within China’s aquatic product processing industry.

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 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.

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 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 understand the exposure of tetrodotoxin in wild and farmed shellfish in coastal cities of Zhejiang Province in 2022. Methods Used stratified random sampling method, liquid chromatography tandem mass spectrometry was used to determine tetrodotoxin in the samples, combined with the Report on nutrition and chronic disease status of Chinese residents (2015) and the 2014 National physical fitness monitoring bulletin to investigated the dietary intake of residents. Using the point assessment method recommended by the World Health Organization/Food and Agriculture Organization of the United Nations for Assessment of dietary exposure to chemicals in food, the level of tetrodotoxin in the diet of residents in several coastal cities in Zhejiang Province was evaluated. Results The content of tetrodotoxin in shellfish varied greatly, mainly concentrated in rainbow cherry clams and striped snails, with a detection rate of 14.7% and a maximum of 5220.00 μg/kg. The average content of tetrodotoxin was 167.30 μg/kg. When children under 10 years old consumed less than 15 g, adolescents aged 10-20 years old consumed less than 40 g, and adults over 20 years old consumed less than 60 g at once, their acute dietary exposure level was in an acceptable and safe state; the acute risk index for ingesting other shellfish was much lower than 100, indicated that the population’s exposure level was in a safe state. Conclusion The overall acute dietary exposure level of shellfish was in a safe state, and the content of tetrodotoxin in striped snails is extremely high. Eating striped snails is extremely unsafe and shall be regulated.

Objective To study the tissue distribution and metabolic regulation of diazepam (DZP) in Carassius auratus after feeding with positive bait containing DZP. Methods Carassius auratus was selected as the study object and exposed to DZP-enriched bait through gavage, and tissue samples including scales, skin, muscle, plasma, gills, intestines, liver, gallbladder, gonads, and brain were collected at specific intervals ranging from 1 h to 456 h post-exposure. High performance liquid chromatography coupled with tandem high-resolution mass spectrometry was employed to detect DZP and its metabolites—nordazepam (NZP), temazepam (TZP), and oxazepam (OZP)—in these tissues, analyze their distribution and metabolic patterns. Results Following exposure to DZP-enriched bait, DZP rapidly accumulated in Carassius auratus tissues, with substantial residues persisting for up to 456 h. The highest concentrations were primarily found in the gonads, liver and gallbladder, with the gonads consistently showing elevated levels. NZP and TZP emerged as the primary metabolites. Conclusion DZP predominantly exists in its prototype form in Carassius auratus and tends to accumulate in the gonads. The prolonged metabolic cycle of DZP and its metabolites in Carassius auratus indicates potential food safety and health risks for consumers of aquatic products caught with DZP-containing bait.

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.

Pathogenic bacteria has always been a hot topic of social concern, which is one of the important factors to harm food safety and public health. Rapid and accurate detection of pathogenic bacteria is of great significance to people’s health and social stability. In recent years, due to the drawbacks of traditional methods such as cumbersome process, low sensitivity and single detection type, researchers have developed various fluorescence sensors for rapid and accurate detection of pathogenic bacteria through reasonable modification of nanoclusters by various means. This paper focused on the physical and chemical properties of gold nanoclusters, summarized the latest research progress of gold nanoclusters for pathogenic bacteria detection from the perspective of direct and indirect reaction from the different modes of action of gold nanoclusters and target bacteria, and discussed and prospects the shortcomings and possible development directions of gold nanoclusters in the future. The aim is to provide reference for the rapid detection of pathogenic bacteria by gold nanoclusters.

Cronobacter spp. is a group of foodborne opportunistic pathogens widely present in the natural environment, characterized by their ability to tolerate desiccation and high osmolarity, enabling them to survive for extended periods in dried milk powder. Infant formula products may become contaminated during production, transportation, storage, and even during the reconstitution process. Infection with Cronobacter spp. can lead to severe illnesses such as bacteremia, meningitis, necrotizing enterocolitis in infants, and may result in serious neurological sequelae or even death. Therefore, establishing efficient and accurate detection methods for Cronobacter spp. is crucial for preventing and controlling these diseases, and holds significant importance in ensuring the quality and safety of infant formula products. Currently, the main detection methods for Cronobacter spp. include traditional culture-based methods, molecular biology methods, and immunological methods, with numerous studies in recent years reporting various degrees of improvement and optimization based on these methods. This article systematically reviewed the principles, advantages, and disadvantages of the various detection methods currently available for Cronobacter spp., aiming to provide a reference for further research in this field and for the optimization and updating of national standards and industry standards.

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 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 growth heterogeneity of different serotypes of Vibrio parahaemolyticus (VP) under different culture conditions, and to establish growth prediction models for epidemic strains (O3:K6, O10:K4). Methods Seventeen VP strains of different serotypes were selected as the research objects, and different culture conditions were set, including salinity (0.5%-10.0%), pH (3.0-11.0) and temperature (16-50 ℃). The modified Gompertz model was used to establish the primary growth model. The optimal growth range was determined by comparing the maximum OD value (Y_max), the Lag time (λ) and maximum specific growth rate (μ_max). The second-order response surface growth model was established by Design-Expert 13 software. Results There was growth heterogeneity among VP strains. The coefficient of variation for differences in growth parameters μ_max and Y_max between VP strains at salinity levels of 1.0%-3.0%, pH of 7.0-9.0, and temperatures of 20-40 ℃ was lower than that under other culture conditions. The growth ability of the epidemic strains (serotype O3:K6, O10:K4) was significantly greater than that of other serotypes when the salinity was 7.0%, the pH was 10.0, and the temperature was 16 ℃, with a statistically significant difference (P<0.05). The determination coefficients of the first-order growth models fitted under different salinity and temperature were greater than 0.98, and the correlation coefficients under different pH were greater than 0.9. The second-order response surface growth model was significant (P<0.05), and the determination coefficient was greater than 0.94. Conclusion There is growth heterogeneity among VP strains, but in certain extreme conditions, there are more obvious growth differences between different serotypes. The modified Gompertz model and the second-order response surface growth model can be used to analyze and predict the growth of VP under different experimental conditions, which can provide reliable and safe prediction for the growth trend of VP.

Objective To develop a rapid method for detecting Salmonella, Escherichia coli O157, Listeria monocytogenes, Staphylococcus aureus, and Vibrio parahaemolyticus using multiplex polymerase chain reaction (PCR) and capillary electrophoresis technology. Methods Specific multiplex PCR primers were designed using conserved pathogenic genes of 5 kinds of foodborne pathogens, and the products were analyzed using capillary electrophoresis imaging. By optimizing the PCR reaction and electrophoresis conditions, a multiplex PCR capillary electrophoresis detection method was established. The specificity and sensitivity were studied as well. Results The specificity of the 5 pairs of primers was acceptable and no non-specific amplification occurred. The optimal primer concentration for multiplex PCR reaction was 0.2 μmol/L, and the optimal annealing temperature was 56.0 ℃. The optimal separation mode for capillary electrophoresis was AM900. The method had a high sensitivity, and the detection sensitivity could reach 5×10^-3 ng/μL. Conclusion The multiplex PCR capillary electrophoresis method for detecting 5 kinds of foodborne pathogens established in this study is simple for operation with high specificity and sensitivity, and can be very practical in detection of foodborne pathogens.

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 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 analyze the changes in microbial content of fresh cut Citrullus lanatus of different varieties over time under normal temperature and refrigeration storage conditions. Methods The 30 batches of 420 samples of the more popular of Kirin, Sweet King, and Black Beauty Citrullus lanatus, were selected as the research objects. After being divided and stored at room temperature and refrigerated conditions for 2, 4, 6, 8, 10, 12, and 24 hours, microbial item detection was carried out to obtain the total bacterial count, coliform count, mold and yeast count, and Staphylococcus aureus microbial contamination. Results The total bacterial count, coliform count, mold and yeast count of the three fresh cut Citrullus lanatus increased with storage time. After being stored at room temperature for 8, 10 and 12 hours, the total bacterial count of Kirin, Sweet King, and Black Beauty Citrullus lanatus exceeded 10⁵ CFU/g, the coliform count exceeded 100 CFU/g after 8 hours, and the total number of mold and yeast count exceeded 100 CFU/g after 10 hours, under refrigeration conditions, the average total bacterial count of Kirin, Sweet King, and Black Beauty Citrullus lanatus stored for 8 hours exceeded 10⁴ CFU/g; the coliform count, total number of molds and yeasts all exceeded 100 CFU/g after 10 hours of storage. Staphylococcus aureus was detected after 4 hours of storage at room temperature and 6 hours of refrigeration, with a total detection rate of 32.86%. Conclusion Fresh cut Citrullus lanatus pose an increased safety risk due to microbial contamination after being stored at room temperature for 8 hours. Consumers should consume them as soon as possible after purchase and store them at low temperatures if necessary.

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 study the suitability of different varieties of Dioscorea esculenta for vacuum frying. Methods Nineteen varieties of Dioscorea esculenta widely cultivated in China were taken as raw materials. Six quality indexes of fried Dioscorea esculenta chips, namely the yield rate, sensory score, breaking force, adhesiveness, color difference, oil content and flavor, were measured, and difference analysis was carried out. Correlation analysis, principal component analysis, stepwise regression analysis methods were applied to explore the model fitting degree and the significance of the regression model. K-means clustering analysis method was used to preliminarily divide the processing suitability of the 19 Dioscorea esculenta varieties. Results Differences were found in the shape, size and color of fried Dioscorea esculenta chips among the 19 Dioscorea esculenta varieties, and correlations existed among the indexes. Taking the yield rate of Dioscorea esculenta (X₁), color difference value L^* (X₂), sensory score (X₃), breaking force (X₄), adhesiveness (X₅) and oil content (X₆) as the initial independent variables, principal component analysis could be conducted and a quality evaluation model for fried Dioscorea esculenta chips was constructed, which was Y=1.02-3.37X₁-0.19X₂+0.16X₃+0.18X₄+3.01X₅+2.43X₆. Among the 19 varieties, Zhan Shu 12, Mian Zi 12, Bai Shu, Chuan Zi Shu No. 6 and 317 were suitable for making chips; Yu Shu 27, Xu Yu No. 31, Qian Zi Shu No. 1, Wan Shu No. 5, Xiang Shu 98, Yu Shu 17, Zi Yun Hong Shu, Yu Shu 198, Qian Shu No. 8, Shang Shu 19, Kao Shu, Yu Shu 9 and Long Shu 9 were basically suitable for making chips; while Tong Shu No. 2 was not suitable for making chips. Conclusion The research results can be referred to when the Dioscorea esculenta industry in China selects specific varieties for chip processing.

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 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.

In recent years, Actinidia industry has developed rapidly in China. The Actinidia plant area and production both rank the first all over the world. The standardization of Actinidia production are becoming higher. But it lacks competitiveness in quality and trade, can not meet the domestic and international market demand for high-quality Actinidia. Therefore, perfecting the quality and safety standard system of Actinidia in our country will be an important method to improve the market competitiveness. This article systematically sorts out China’s current Actinidia quality and safety standards, summarizes the quality and safety of each link of Actinidia before, during and after production, analyzes the current situation of China’s Actinidia quality standard system construction, as well as the main problems, and puts forward suggestions for the construction of the whole process of Actinidia quality and safety control system, in order to promote the high quality development of China’s Actinidia industry.

Objective Microorganisms are significant factors affecting food safety. Contamination of food by microorganisms can lead to spoilage and deterioration, resulting in substantial economic losses. Moreover, many microorganisms possess pathogenicity, and the toxins they secrete are the main cause of foodborne diseases. Therefore, microbiological testing of food has important sanitary and social significance. With the development of the food industry, traditional plate separation methods, due to their long detection times and complex operations, are increasingly unable to meet the current demand for rapid testing. microbiological test tablets are a new type of detection tool, with the advantages of easy operation, no need for culture medium preparation, and space-saving in detection. In recent years, researchers have conducted extensive studies on test tablets for different microorganisms. This article organizes these studies, thoroughly combs the composition and principles of test tablets, analyzes their advantages and existing problems, and has certain theoretical value and practical guidance significance. It is hoped to provide some ideas for the research of microbiological test tablets.

Objective To compare the differences in spectral characteristics and monocyte immune effects for bacterial endotoxin from different sources. Methods Ultraviolet absorption spectrum and three-dimensional fluorescence spectrum were used to identify excipients (polyethylene glycol 8000 and α-lactose) and biological impurities (protein and nucleic acid) in 5 kinds of control standard endotoxin. Biological contamination was further confirmed by the detection of Toll-like receptors (TLRs) in HL-60 cells. The monocyte activation test was used to compare the release of the inflammatory cytokines interleukin 6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) caused by 5 kinds of endotoxins on HL-60 cells. Results As for control standard endotoxin, absorption peaks related to excipients were observed in ultraviolet absorption spectrum, while fluorescence peaks related to excipients and proteins were shown in three-dimensional fluorescence spectrum. The expression levels of TLRs of HL-60 cells indicated that protein contamination was more significant than nucleic acid contamination. All endotoxins induced improvement in cellular IL-6 and IL-1β gene relative expression levels and their protein mass concentrations in HL-60 cells. However, the TNF-α gene relative expression levels and its protein concentrations were not elevated. Endotoxins from the same or different bacterial strains had significant differences in their ability to induce inflammation under the same endotoxin activities. Conclusion Excipients and protein contamination of endotoxins are identified by spectral detection, while proteins and nucleic acids in biological impurity are confirmed by the TLRs assay of HL-60 cells. Molecular structure of endotoxins, as well as protein contamination influence the ability of endotoxins to induce the release of the inflammatory cytokines.

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 investigate the effects of shading and drought on the quality of black tea and white tea in summer and autumn. Methods Light fermented white tea and heavy fermented black tea were processed through multiple experimental settings of shade, drought, and a combination of shade and drought. The 4 groups of black tea and white tea samples were evaluated for sensory quality. Additionally, high performance liquid chromatography (HPLC) and headspace solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) technologies were employed to conduct a comparative analysis of quality components and taste components. Results Shading combined with drought treatment increased the levels of water extracts, free amino acids, umami amino acids such as theanine, sweet amino acids like threonine, alcohols, thereby significantly enhanced the fresh taste of the tea (P<0.05). Concurrently, in black tea, the concentrations of bitter amino acids such as valine, tea polyphenols, catechins were reduced, leading to a marked decrease in the bitterness and astringency of summer and autumn tea (P<0.05). Aroma testing revealed a total of 98 substances in black tea, with alcohols being the most prevalent. The concentration in the shade plus drought group was significantly higher than the drought group (P<0.05). In white tea, 85 substances were identified, with alcohols comprising the largest proportion. Conclusion The findings of this study offer new insights for the production of black and white tea under extreme summer and autumn weather conditions. This approach not only effectively mitigates the bitterness of summer and autumn tea but also enhances the utilization rate of fresh leaves, providing crucial guidance for tea garden production management.

Objective To explore the types and contents of amino acids in Asparagus from different sources. Methods Post-column ninhydrin-derived photometry was established to determine the species and contents of amino acids in Guangxi, Neijiang and southwest winter, and performed data analysis using stoichiometry. Results The average amino acid content in Neijiang was 3.06%, 3.53% in Guangxi, and 5.73% in southwest China. The amino acid composition and content in Neijiang and Guangxi were similar, and the content was uniform among different batches, the amino acid content in southwest and southwest was quite different from the first two sources, and the different batches were quite different. Conclusion This research provides scientific reference for quality evaluation of Asparagus and the study of its authenticity.

Objective To synthesize a Au-Pt bimetallic nanozymes (Au-PtNFs) with oxidase and peroxidase dual-enzyme activity, and apply them in detection of organophosphorus pesticide. Methods The 3 kinds of Au-PtNFs were prepared through seed-mediated method by adjusting the amount of chloroplatinic acid, and their enzyme activities were determined using 3,3’,5,5’-tetramethylbenzidine (TMB) as the substrate. The nanozyme exhibiting the highest enzyme activity was selected and combined with the catalytic effect of acetylcholinesterase to establish a detection method for organophosphorus pesticide. Results The 3 kinds of prepared nanozymes all had flower-like structures, and the particle size enhanced with the increasement of chloroplatinic acid concentration. Steady-state dynamic experiments showed that all bimetallic nanozymes had dual-enzyme activity, and the best enzyme activity was obtained when the concentration of chloroplatinic acid was 5 mmol/L. Absorption at 620 nm exhibited a good linear correlation with the logarithm of chlorpyrifos concentration in the range of 40-90 nmol/L, and the limit of detection was 1.00 nmol/L. The method demonstrated excellent specificity and anti-interference ability, and achieved great recovery rate in real samples. Color value analysis software was used for the detection of chlorpyrifos based on smartphone. The linear range was 30-100 nmol/L and the limit of detection was 1.06 nmol/L. Conclusion The prepared Au-PtNFs exhibiting dual-enzyme activity are effectively utilized for detection of organophosphorus pesticides, which offers a novel perspective for visual detection of organophosphorus pesticides in fruits and vegetables.

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.

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 a highly sensitive analytical method for the determination of advantame in alcoholic beverages by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Methods The wine samples were diluted 10 times with ultrapure water, filtered through a membrane, and then injected. A Kinetex^® Biphenyl 100 Å chromatographic column (100 mm×3.0 mm, 2.6 μm) was used, with water and methanol as the mobile phase for gradient elution and separation. An electrospray ionization source (ESI) was adopted for detection in the positive ion scan multiple reaction monitoring (+MRM) mode, and external standard method was used for quantification. Results Advantame exhibited an excellent linear relationship within the mass concentration range of 0.03 to 40.00 μg/L, with a correlation coefficient of 0.9999. The limit of detection was 0.10 μg/kg, the limit of quantification was 0.30 μg/kg. The average recoveries at the 4 different spiked levels of low, medium-low, medium-high and high were 80.8% to 109.8%, and the relative standard deviation was 2.7% to 12.5% (n=6). Conclusion This method has high detection sensitivity, is simple to operate, accurate and reliable, and can be used for the trace analysis and risk assessment of advantame in alcoholic foods, providing strong technical support for scientific supervision of the alcoholic beverage market.