In the economic shellfish farming on coastal mudflats in China, the Sinovovacula constricta occupies an important position. In recent years, due to the rapid urbanization and industrialization in China, marine pollution has threatened the living environment of Sinovovacula constricta. Polluted Sinovovacula constricta can accumulate toxins in their bodies, which can be transmitted through the food chain and ultimately endanger human health. Therefore, the food safety issue of Sinovovacula constricta has received widespread attention. With the continuous improvement of the transportation network and the gradual maturity of the live-keeping technology system, more and more Sinovovacula constricta are being sent to inland areas, expanding the consumer market. Therefore, Sinovovacula constricta must undergo purification treatment before entering the circulation process. As consumers' demands for the taste and quality of fresh Sinovovacula constricta continue to increase, the purification and live-keeping processes of Sinovovacula constricta have become particularly important. This article reviewed the current research progress in the purification methods of Sinovovacula constricta in China, the advantages and limitations of different purification processes, the influences of environmental parameters on purification, and live-keeping technologies, providing a reference for in-depth research on the purification and live-keeping technologies of Sinovovacula constricta.

Objective To evaluate and determine the key volatile aroma components of Jinzhuguo Pyrus. Methods Head space-solid phase microextractio (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) were used to separate and identify the volatile aroma components in the peel, pulp and juice of Jinzhuguo Pyrus. The odor activity value (OAV) was determined by combining the odor threshold to evaluate the contribution of various aroma components. Results The results indicated that the common key flavor compounds in the peel, pulp and juice of Jinzhuguo Pyrus were ethyl n-hexanoate, ethyl butyrate, ethyl octanoate and nonal. The unique key flavor compounds in the peel samples were hexyl butyrate (OAV 2.34), ethyl cromarate (OAV 1.93) and dammasone (OAV 675) in the peel, pulp and juice samples, respectively. The relative content of volatile aroma components in peel, pulp and juice was 88.19%, 76.46% and 39.94%, respectively. Conclusion The OAV of Jinzhuguo Pyrus juice is higher, while it is lower in pulp and peel, making them more suitable for making processed products.

Objective To study the characteristics of volatile flavor substances in beef jerky products processed by different processing methods. Methods Beef was processed by different processing methods (15 kinds of curing, bacterial curing, air-drying, etc.), and analyzed by headspace solid-phase microextraction combined with comprehensive two-dimensional gas chromatography-time of flight mass spectrometry. Results The differential metabolites in 15 kinds of samples were detected. Among them, during the pickling process of Staphylococcus xylosus, Lactobacillus plantarum and Pediococcus pentosaceus, the significant differential metabolites included 12 kinds of sugars, acids and esters. The cured beef processed by air-drying method and the cured beef with bacteria produced 8 kinds of extremely significant different metabolites such as maltose, decanoic acid and orotic acid after air-drying. More than 11 kinds of differential metabolites including naphthalene, 3-hydroxy-DL-norvaline, L-menthone, n-decanoic acid, D-pinobiose and myristic acid were detected in the cured beef processed by normal baking than in the cured beef processed by vacuum baking. The metabolic pathways involved in vacuum baking were citric acid cycle, alanine, aspartic acid and glutamic acid metabolism, and the metabolic pathways involved in baking were amino sugar and nucleotide sugar metabolism. Conclusion In this study, the changes of volatile flavor substances in beef jerky products with different processing methods are analyzed, which provide methodological guidance for improving the quality and taste of air-drying beef.

Objective To study the effect of n-3 polyunsaturated phosphatidylserine on the anti-apoptotic ability of rat hippocampal neuron cells (RHNC). Methods An apoptosis model using RHNC as the target and phorbol acetate (PMA) as the inducer was established. Using docosahexaenoic acid (DHA)/eicosapentaenoic acid (EPA) phosphatidylserine (DHA/EPA-PS) as a protective agent, the morphology of cells at different stages of apoptosis was observed under a laser confocal microscope after staining with acridine orange. The effect of n-3 polyunsaturated phosphatidylserine, represented by DHA/EPA-PS, on the anti-apoptotic ability of RHNC was studied at the cellular level through the Annexin V-FITC/PI double staining experiment. Results An RHNC apoptosis model with a PMA concentration of 10.0 mg/L and an action time of 24 hours was established. The 15.0 mg/L DHA/EPA-PS showed the best cell pre protection effect, with an apoptosis rate of 11.46%±4.11%. Early and mid-stage apoptotic cells were fewer and did not produce late stage apoptotic cells. Cells pre protected with 15 mg/L DHA/EPA-PS exhibited intact morphology and nuclear membrane, and their protrusions were not affected by PMA. Conclusion n-3 polyunsaturated phosphatidylserine, represented by DHA/EPA-PS, has certain anti-apoptotic ability against RHNC. The study provides good data support for future research on the biological activity of phosphatidylserine.

Objective To investigate the key factors that may influence plasmin activity during the production of ultra high temperature (UHT) milk. Methods An enzyme-linked immunosorbent assay (ELISA) was employed to assess and analyze the effects of various factors on plasmin activity throughout the UHT milk production process. The specific factors examined included the degree of mastitis in cows, somatic cell count in milk, vaccination status, changes in feeding conditions, centrifugation processes, pasteurization preheating conditions, microfiltration techniques, and UHT preheating conditions. Results At the raw milk stage, a significant positive correlation was observed between plasmin activity levels in bovine milk and both the severity of bovine mastitis and somatic cell counts. However, no significant correlation was found regarding vaccination status or changes in feed type. During UHT milk production, centrifugal sterilization resulted in a slight increase in plasmin activity; pasteurization preheating at 55 ℃ proved most effective at inhibiting this increase. Microfiltration reduced plasmin activity by approximately 10%. Additionally, varying UHT preheating conditions led to an overall increase in enzyme activity; however, under treatment at 90 ℃ for 5 seconds, a condition yielding only a minimal increase of 1.52%, the rise remained relatively low. Conclusion For pasture, it is essential to focus on managing cows with mastitis and monitoring those milk with abnormal somatic cell counts. At the processing stage, implementing appropriate preheating conditions for pasteurization and UHT can effectively inhibit increases in plasmin activity within milk. Furthermore, incorporating microfiltration can serve as an additional strategy to reduce such enzymatic activities. This study provides a scientific foundation for further research aimed at controlling elevations of plasmin activity in UHT milk.

Objective To explore the factors affecting protease activity in raw milk. Methods Used raw milk and milk samples before and after different processing techniques as samples, acid, alkali and neutral protease activities were determined based on the Folin phenol method. The effects of different regions, seasons, ranch temperatures, somatic cell numbers, number of psychrophilic bacteria, and behavioral stress on protease activity in milk samples were analyzed at the ranch and process levels, and the effects of different processing techniques on product protease activity were analyzed. Results The contribution rate of protease activity changes at the ranch level was in the following order: Season (resulting in temperature changes)>highest temperature on the ranch>region>number of psychrophilic bacteria>number of somatic cells. In the comparison of protease inactivation rates under different treatment processes, the 4 treatment processes had the following order of protease inactivation rate: Ultra-high temperature treated (UHT) preheating treatment (90 ℃, 5 s)>pre heat treatment before sterilization (70 ℃, 5 s)>reverse osmosis (RO)>centrifugal sterilization. Conclusion The main influencing factor at the ranch level is the seasonal temperature changes that affect protease activity, simultaneously using preheating treatment before sterilization at the process level can achieve a protease inactivation rate of over 50%.

Objective To evaluate the edible safety of marine aquaculture Monostromanitdum along the coast of Naozhou Island. Methods Using 4 kinds of different collection times of Monostromanitdum as research objects, microwave digestion, inductively coupled plasma mass spectrometry, and atomic fluorescence spectroscopy were used to analyze the content of 5 kinds of heavy metals, Cr, As, Pb, Hg, and Cd, in Monostromanitdum samples, and microbial indicators were determined. Using acute oral toxicity experiments on mice, the food safety of Monostromanitdum was evaluated by analyzing indicators such as drinking water, diet, body weight, organ coefficient, mortality rate, and appearance of mice. Results The content of Cr, As, Pb, and Hg in the sample far exceeded the food safety content specified by the national standard, with the maximum being 29.20, 12.12, 3.59 and 3.70 times the limit values, respectively. The total number of bacterial colonies in the samples exceeded 50 CFU/g. The mice in the group administered with Monostromanitdum by gavage showed signs of death, with organ coefficients increasing in all organs except for the liver, and the appearance changes consistent with heavy metal poisoning. Conclusion There are safety risks associated with consuming unprocessed Monostromanitdum, and the safety of direct consumption is relatively low.

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 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 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.