To establish a method for the rapid determination of 6 kinds of biogenic amines in fermented milk by pass-through solid-phase extraction coupled with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS).

After extraction with a 2% formic acid/acetonitrile solution, samples were purified using an Oasis PRiME HLB solid-phase extraction cartridge to efficiently remove interferences such as proteins and phospholipids. Chromatographic separation was performed on a hydrophilic interaction chromatography column. Mass spectrometric detection was carried out in multiple reaction monitoring mode, and quantification was achieved by the internal standard method.

The method was validated and demonstrated good linearity (r²≥0.996)for the 6 kinds of biogenic amines within a certain concentration range, the limits of detection were 0.20 µg/kg–1.80 µg/kg,the limits of quantitation were 0.67–6.00 µg/kg. Spiked recoveries were 76.0%–117.8%, with relative standard deviations below 13%. Analysis of commercial fermented dairy samples revealed that tyramine was the predominant biogenic amine, with concentrations ranging from 0.80 to 1.70 mg/kg, while safety-risk-associated biogenic amines such as histamine were detected at extremely low levels or were not detected.

The established method,by incorporating the Oasis PRiME HLB purification strategy, effectively resolves the critical issue of phospholipid interference in dairy products. It features advantages such as simple and rapid sample preparation, high sensitivity and strong anti-interference capability. The method is suitable for the high-throughput determination of multiple biogenic amines in fermented dairy products, providing robust technical support for the quality control and safety risk assessment of these products.

To construct a standard fingerprint of monosaccharides in edible bird’s nest by gas chromatography-mass spectrometry (GC-MS), and identify the adulteration of edible bird’s nest.

Taking edible bird’s nest as the research object, 34 batches of monosaccharides in edible bird’s nest from different suppliers were analyzed by GC-MS. And a standard fingerprint of monosaccharides in edible bird’s nest was established using the“similarity evaluation system of traditional Chinese medicine chromatographic fingerprint”. The fingerprint was used to identify adulteration models of tremella fuciformis polysaccharide, yellow gelatin, pectin, gellan gum, carrageenan and agar with adulteration amounts of 1%, 5%, 10%, 20%, 30%, 40% and 50%, respectively.

Edible bird’s nest contains 5 kinds of monosaccharide components: fucose, mannose, galactose, acetylglucosamine and acetylgalactosamine, with an average relative mass ratio of 1:1.5:8.4:6.6:4.1, and the total sugar content ranging from 18.75 g/100 g to 23.92 g/100 g, through similarity evaluation, the similarity of 34 batches of edible bird’s nests was more than 99.5%, meeting the requirements of fingerprint similarity evaluation. Taking a similarity of 99.8% as the identification standard for edible bird’s nests, when the adulteration level ranges from 1% to 50%, the fingerprint adulteration model could effectively predict the adulteration level and achieve adulteration identification.

This study analyzes the monosaccharide composition of edible bird’s nest and established a GC-MS-based standard monosaccharide fingerprint and adulteration model. This approach enables effective identification of common adulterants and quantification of adulteration ratios, offering data and technical support for market supervision.

To investigate the characteristics of pesticide residue contamination in commercially available vegetables in Shaanxi Province and assess the dietary risk of local residents through vegetable consumption.

Based on the monitoring data of 25 kinds of pesticide residues in 765 samples of 8 major categories of commercially available vegetables from 10 cities in Shaanxi Province from 2022 to 2024, the pesticide residue contamination was investigated from different aspects such as different pesticide varieties, different vegetable species, different regional distributions and utilization of multiple pesticides. Acute and chronic dietary intake risk assessment (DIRA) was conducted and the overall risk level was determined through the index of food safety (IFS).

The 23 kinds of pesticide residues were detected in vegetable samples, with an overall detection rate of 58.17% and an exceeding rate of 2.35%. Prohibited and restricted pesticides were detected in 24 samples, among which dimethoate, omethoate and phorate were found to exceed the maximum residue limits upon detection. The detection rate of individual indicators ranged from 0.13% to 25.49% and the exceeding rates ranged from 0.13% to 0.65%. Leafy vegetables (74.31%) had the highest detection rate and the co-use of multiple pesticides was the most prominent. Exceedance samples were found in leafy vegetables (4.74%), bulb vegetables (3.51%) and fruit vegetables(3.01%). The extreme values of detection in the Shannan region were relatively high and the Guanzhong region contributed 72.22% of the exceedance cases in the province. The percentage of acute reference dose (%ARfD) of omethoate was 399.67%, while the %ARfD and percentage of acceptable daily intake (%ADI) of the other evaluated pesticides were all less than 100%. The IFS of each individual pesticide was less than 1 and the mean index of food safety () of vegetables was less than 1.

The pesticide residues in commercially available vegetables in Shaanxi Province show a high detection rate and a low exceeding rate, and the phenomenon of multiple pesticide co-use in leafy vegetables is quite prominent. Except for omethoate, the acute and chronic dietary exposure risks of other pesticides are within acceptable limits. The overall safety risk of vegetables is controllable. The illegal use of prohibited and restricted pesticides and the acute dietary exposure risk of omethoate are the main factors affecting vegetable quality. The findings of this study may provide data support for refining local regulatory strategies and implementing dietary risk warnings for residents.

To investigate the quality and safety status of commercially available seasoned flour products in Yueyang City, in 2025, and to elucidate their quality control practicess and risk characteristics.

A total of 70 batches of commercially available samples were collected from Yueyang City, Hunan Province. The 11 parameters, including acid value, peroxide value, preservatives, sweeteners and microbiological indicators, were analyzed in accordance with national food safety standards. Furthermore, the quality and safety profiles were evaluated in conjunction with packaging forms and shelf-life characteristics.

The market for seasoned flour products exhibited structural characteristic of “lightweight packaging and medium-to-long shelf life”. Pre-packaged products accounted for 64.29% of the total, with specifications of 25–50 g dominating the mainstream market, and products with a shelf life of 150 days representing 72.86%. Traditional preservatives (benzoic acid, sorbic acid, and dehydroacetic acid) were not detected in any samples. However, the issue of excessive sweetener levels was prominent: The unqualified rates for sodium cyclamate and sucralose were 1.43% and 5.71%, respectively. And all the trichlorosucrose unqualified samples were filamentous or rod-shaped products. Microbial contamination was mainly indicated by the total number of colonies, with a detection rate of 38.57% and an unqualified rate of 2.86%.The detection rates of coliform bacteria and mold were both 1.43% and did not exceed the standards. The detected samples were completely consistent with the samples with total colony counts.

The traditional preservatives in the seasoned flour products sell in Yueyang City are well controlled, but the excessive use of sweeteners and the problem of microbial contamination still exist. The product form and the dosage of additives show a potential process correlation.

To investigate the pollution status of 6 kinds of metal elements in different categories of vegetables sold in Xingtai Area, and assess the health risks to the population.

Microwave digestion was performed on 296 vegetable samples purchased from local markets, and the samples were analyzed by inductively coupled plasma mass spectrometry and atomic fluorescence spectrometry. The pollution levels of the 6 kinds of metal elements in the vegetables were evaluated using the single-factor pollution index and the Nemerow comprehensive pollution index. The health risks associated with residents’ dietary intake of these metals were assessed by the target hazard quotient (THQ) and total target hazard quotient (TTHQ) methods.

Chromium had the highest detection rate among the metal elements in vegetables, reaching 85.1%, with an average content of 0.1090 mg/kg and an exceedance rate of 1.7%. Among different categories of vegetables, aquatic vegetables showed the highest metal chromium content, with an average of 0.318 mg/kg and an exceedance rate of 3.7%. Correlation analysis revealed a highly significant positive correlation between chromium and nickel (r=0.629, P<0.01). In addition, pairwise associated relationships were observed between chromium and plumbum (r=0.460), nickel and plumbum (r=0.435),and cadmium and chromium (r=0.403). The Nemerow comprehensive pollution index ranged from 0.011 to 0.636 across the 8 vegetable categories, indicating an overall “excellent” level of metal pollution. Aquatic vegetables exhibited relatively high combined heavy metal risks, with TTHQ values of 1.4571, 1.2359 and 0.9857 for children,young and middle-aged adults and the elderly, respectively.

Metallic elements are detected at relatively high rates in vegetables sold in Xingtai, and aquatic vegetables may pose a certain exposure risk to human health.Meanwhile, children face significantly higher health risks from metal exposure compared with adults.

To establish a compound-specific isotope profiling method by liquid chromatography-high-resolution mass spectrometry (LC-HRMS) for identify caffeine and lovastatin derived from natural extraction, chemical synthesis and bioengineered fermentation in food matrices.

Waters XBridge BEH C₁₈ column (250 mm×4.6 mm, 5 μm) coupled with a mild elution gradient was used to moderately broaden the chromatographic elution window of target compounds. A quadrupole-orbitrap mass spectrometer operated at a resolution of 140000 full width at half maximum (FWHM) was used to continuously acquire the complete isotopic peaks of target molecules at no fewer than 20 non-equidistant time points within each chromatographic peak. During data processing, a theoretical correction model was applied to subtract heteroatom isotope contributions. Grubbs’outlier test and the pruned exact linear time (PELT) change-point detection algorithm were then used to quantify intra-peak isotopic heterogeneity and stepwise shifts. Full-elution deconvolution was further used to construct a two-dimensional isotope landscape model of the food matrix.

Caffeine from natural tea sources, chemical synthesis and bioengineered fermentation, as well as lovastatin from natural red-yeast fermentation and pharmaceutical-grade sources, showed distinct baseline isotopic fingerprints. In simulated adulteration systems,when exogenous synthetic substances accounted for 10% of the total target compound, the PELT algorithm accurately detected isotope-ratio change points at the P<0.01 confidence level; When the proportion was greater than or equal to 20%, stepwise transition points were reliably localized. The adulteration proportions back-calculated using the isotope mass-balance model showed relative deviations within ±15%. Over the concentration range of 0.1–10.0 μg/mL, the 5 consecutive days of testing gave an inter-day relative standard deviation of 0.8% for δ¹³C, with a maximum systematic bias of +0.8‰, demonstrating high precision and strong resistance to matrix interference.

The multidimensional isotope-profile time-series method established in this study enables qualitative differentiation between natural and artificially synthesize forms of the same molecule by exploiting chromatographic isotope fractionation without requiring complete chromatographic separation. This approach provides a feasible technical solution for resolving source-identification challenges involving substances with overlapping natural occurrence and artificial addition, and offers a methodological reference for improving food safety regulatory strategies.

To screen the differential metabolites of amino acids during the autolysis process of the Coprinellus micaceus by amino acid targeted metabolomics, and analyze the potential pathways of its autolysis process.

The samples of Coprinellus micaceus were collected, the samples were divided into a control group and an autolysis group, with 6 samples in each group, totaling 12 samples. The 24 kinds of amino acids in the samples were detected by ultra-performance liquid chromatography-tandem mass spectrometry. The sample repeatability and the trend of overall metabolic differences were evaluated through multivariate statistical principal component analysis (PCA). Orthogonal partial least squares discriminant analysis (OPLS-DA) maximizes differences between groups and screens for differential metabolites and the Kyoto encyclopedia of genes and genomes (KEGG)pathway enrichment analysis was conducted for the differential metabolites.

Through PCA and OPLS-DA,the contribution rate of principal component 1 (PC1) was 52.6%, and that of principal component 2 (PC2) was 24.1%.The autolysis group (R) and the control group (W) were completely separated, and the amino acid metabolites of Coprinellus micaceus disseminatus during autolysis showed significant differences. Differential metabolites were screened under the conditions of variable importance projection (VIP)≥1, P<0.05, and |log₂FC|≥0.58. The differential amino acids during the autolysis of Coprinellus micaceus were ornithine downregulated by 2.7-fold, and tryptophan, citrulline and cysteine upregulated by 1.8-fold, 2.5-fold and 1.9-fold, respectively. Cluster analysis results showed significant differences in amino acid metabolites between the autolysis group and the control group.Cysteine, tryptophan, and citrulline were significantly highly expressed in the autolysis group and stably lowly expressed in the control group, while the expression pattern of ornithine was completely opposite to that of the 3 metabolites. Pearson correlation analysis showed that there were extremely significant positive correlations between cysteine, citrulline and tryptophan (P<0.01), while all 3 showed significant negative correlations with ornithine(P<0.05). Enrichment analysis was performed on the significantly different amino acid metabolites. The results showed that the potential core highly enriched pathway in the autolysis of Coprinellus micaceus was the amino acid biosynthesis pathway, the sub-core highly enriched pathway was the biosynthesis of plant secondary metabolites and the moderately enriched pathways included arginine biosynthesis, glycine, serine and threonine metabolism,glutathione metabolism, 2-oxocarboxylic acid metabolism, central carbon metabolism in cancer, aminoacyl-tRNA biosynthesis, D-amino acid metabolism, protein digestion and absorption, and cofactor biosynthesis.

Ornithine, tryptophan, citrulline and cysteine are screen and identify as the key differential metabolites in the autolysis process of Coprinellus micaceus. These 4 kinds of amino acid differential metabolites can synergistically regulate the autolysis process of Coprinellus micaceus through multiple potential pathways. The results of this study can provide data support and scientific basis for the preservation and storage of macrofungi, optimization of processing techniques, and comprehensive development and utilization of resources.