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.