Objective To compare the mold counting effects of potato dextrose agar and rose Bengal agar as 2 types of counting culture medium. Methods Growth rate, specificity, and selectivity were compared between potato dextrose agar and rose Bengal agar culture medium using 20 kinds of standard mold strains and 15 kinds of common foodborne pathogen strains. Additionally, the counting effects of both culture medium were assessed using 36 actual food samples and 174 swab samples from food contact environments in refrigerators. Results The growth rate (PR value) of the 20 kinds of mold strains on both potato dextrose agar and rose Bengal agar culture medium was greater than 0.7, and the selectivity (G value) was less than 1. However, molds on potato dextrose agar culture medium exhibited more typical colony morphology, indicating better specificity than rose Bengal agar culture medium. In the detection of actual samples, the detection rate of potato dextrose agar culture medium was relatively high, showing a significant difference compared to rose Bengal agar culture medium (χ²=13.551, P=0.001). It exhibited a particularly higher detection rate in samples with low contamination (χ²=9.929, P=0.001). However, for highly contaminated samples, rose Bengal agar culture medium was more convenient for counting. Conclusion Using a single culture medium can affect counting results. It is recommended to apply 2 types of culture medium or select an appropriate counting medium based on the contamination level when conducting mold counting tests on food samples.

Objective To analyse the types and content of metabolites in the stems and leaves of Platycodon grandiflorus by ultra performance liquid chromatography-Quadrupole/Orbitrap high-resolution mass spectrometry (UPLC-Q/Orbitrap HRMS). Methods Stems and leaves of two-year-old purple flowered Platycodon grandiflorus from different sources was used as experimental materials. UPLC-Q/Orbitrap HRMS technology was used to analyze the extracts of Platycodon grandiflorus stems and leaves in negative ion mode, using orbitrap for MS1 full scan and data dependent acquisition ion trap for MS2 scan, and screen for differential metabolites of Platycodon grandiflorum stems and leaves from different sources. Results A total of 18 metabolites were detected in the stems and leaves of Platycodon grandiflorum, including 4 flavonoids, 2 alkynyl glycosides, and 12 saponins (1 metabolite that had not been reported). The basic structure of this unknown compound was polygalacic acid-glucose- xylose/arabic glycoside. Through comparative analysis, differences in chemical composition of Platycodon grandiflorus among different sources were discovered. The 6 differential metabolites of Platycodon grandiflorus from China and South Korea and 1 differential metabolite of Platycodon grandiflorus from Yanbian area were screened. Conclusion The comprehensive analysis results indicate that the stems and leaves of Platycodon grandiflorus have rich chemical components, and the stems and leaves of Platycodon grandiflorus from different sources have compound differences, which have high development and utilization prospects, providing theoretical basis for the development and utilization of aboveground resources of Platycodon grandiflorus.

Objective To investigate the extent of lead contamination in commercial foods and assess the health risk from dietary lead intake of the residents in Guangzhou in 2023. Methods In 2023, the 310 samples were collected from 3 food categories in 11 districts of Guangzhou, China. Lead was measured in the samples using inductively coupled plasma mass spectrometry. Dietary exposure to lead was calculated based on the food consumption survey of Guangzhou residents in 2011, and the health risk of the population was evaluated using the margin of exposure (MOE) method. Results Lead was detected in 83.23% of the overall samples, and the over-standard rate was 0%, with an average lead content of 0.040 mg/kg. The highest lead level was found in bivalves, 0.205 mg/kg. The average daily dietary lead exposure of the whole population and all age groups (3-6 years old, 7-17 years old, 18-59 years old, and 60 years old and above) in Guangzhou and the consumers with high dietary exposure of all age groups (95th percentile P₉₅) were: 0.082, 0.120, 0.097, 0.078, 0.081 μg/(kg·d) and 0.225, 0.330, 0.268, 0.206, 0.226 μg/(kg·d). The contribution of rice and rice products, brassica vegetables, and leafy vegetables to dietary lead exposure was relatively significant. The MOE values for lead in residents of all age groups were greater than 1, with the MOE values for minors being lower than those for adults, particularly among high dietary exposure populations. Conclusion In 2023, there is a certain degree of lead contamination in the food items under close watch in the Guangzhou market. The average dietary lead exposure of residents of all age groups is within the acceptable range. However, it is still necessary to pay attention to key food items and take measures to reduce the dietary lead exposure risk for residents in Guangzhou.

Tricholoma matsutake is a high-quality edible wild fungi in China, rich in a variety of nutritional constituents. Research shows that Tricholoma matsutake contains Tricholoma matsutake polysaccharides, Tricholoma matsutake proteins, Tricholoma matsutake polyphenols, sugar alcohols and other nutrients, high nutritional value, delicious taste, with the promotion of intestinal peristalsis, antioxidant, activation of the immune system, anticancer, antihypertension, antidiabetic and other efficacy, is known as “King of Fungi”. The principal production regions of Tricholoma matsutake in China is divided into the southwest region, such as Sichuan Province, Yunnan Province and other places, as well as the northeastern region, such as Heilongjiang Province, Jilin Province. Due to the different genetic backgrounds and growth environments of different production areas, the types and content of nutrients contained in Tricholoma matsutake are also different. Tapping into the nutritional quality characteristics of local Tricholoma matsutake is the basis for developing local specialty Tricholoma matsutake industry and creating regional brands. This paper systematically summarized and compared the main nutritional characteristics of the Tricholoma matsutake produced in the main producing regions of China. In general, the total fat content of the matsutake mushrooms in the producing regions was lower and the protein content was higher, among which the amino acid and crude fiber contents were higher in the southwestern producing region, while the northeastern producing region had lower fat content and higher average protein content. This review will provide new ideas and theoretical basis for the development of specialty food and health food of Tricholoma matsutake in each production area in China.

Objective To establish an efficient method for assessing the authenticity of Citrus reticulata Blanco honey. Methods High performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was utilized for the qualitative and quantitative analysis of plant compounds present in Citrus reticulata Blanco honey. The authenticity of commercially available Citrus reticulata Blanco honey was evaluated by integrating characteristic components with HPLC fingerprints. Results A total of 6 kinds of components were identified in Citrus reticulata Blanco honey, namely caffeine, cis,trans-abscisic acid, 5-methoxybrevosin, pinocembrin, kaempferol and chrysin. Caffeine exhibited a relatively high concentration, with an average content of 9.45 mg/kg. Thus, it was regarded as a characteristic component of Citrus reticulata Blanco honey. The authenticity assessment of 6 kinds of Citrus reticulata Blanco honeys available on the market revealed that 4 brands exhibited superior quality, one brand might be adulterated with other components, and one brand could potentially be counterfeit Citrus reticulata Blanco honey. Conclusion This study presents a novel methodology that synergistically combines characteristic component profiling with HPLC-fingerprinting technology for authenticity assessment of Citrus reticulata Blanco honey. This study provides a theoretical foundation for grading Citrus reticulata Blanco honey and enhancing its added value.

Objective To explore the contents of 7 kinds of elements in agricultural products in a certain area in North China plain, including lead (Pb), cadmium (Cd), mercury (Hg), arsenic (As), tin (Sn), nickel (Ni) and chromium (Cr), and evaluate the safety risks of dietary ingestion. Methods The samples were pretreated by microwave digestion, and the contents of 7 kinds of heavy metals in 611 agricultural products collected in the certain area from 2022 to 2024 were determined by inductively coupled plasma mass spectrometry (ICP-MS). Index (P_i), Nemero comprehensive pollutant index (P_N) and target hazard quotient/total target hazard quota (THQ/TTHQ) were used to evaluate the pollution levels of heavy metals in agricultural products. Results All elements except Hg were detected in the agricultural products. Among them, the content of Pb and Cr in individual samples exceeded the limit values specified in GB 2762—2022 National food safety standard-Limits of contaminants in foods (Pb≤0.2 mg/kg, Cr≤0.5 mg/kg). The overall content levels of the 7 kinds of elements were relatively low, and their order in the agricultural products was Ni (0.192 mg/kg)>Cr (0.040 mg/kg)>Pb (0.017 mg/kg)>Sn (0.011 mg/kg)>As (0.009 mg/kg)>Cd (0.005 mg/kg), the heavy metal content of agricultural products in different types and regions was quite different, and the THQ/TTHQ of all agricultural products was less than 1, and the P_i and P_N were less than 1. Conclusion The quality and safety of agricultural products in the study area are in good condition, and the level of heavy metal pollution is relatively low. However, there may be potential heavy metal exposure risks in some individual villages and towns in the southeastern part, and the dietary exposure risks for children are greater than those for adults.

Objective To investigate the feasibility of using the adenosine triphosphate (ATP) bioluminescence method for detecting the colonies number in chilled meat, and compare its performance with the national standard plate count method. Methods Effects of different concentrations of Triton X-100 and adenosine triphosphate double (Apyrase) on the remove of ATP from the somatic cells of chilled meat were determined. The colonies number in the chilled meat was measured using both the ATP bioluminescence method and the national standard plate count method, and the reproducibility of the ATP bioluminescence method was evaluated. Results The optimal concentrations of Triton X-100 and Apyrase for ATP removal from the somatic cells of chilled meat were found to be 0.2% and 0.10 U/mL, respectively, with the best ATP removal effect observed at these concentrations. The results of the ATP bioluminescence method and the national standard plate count method demonstrated a strong linear relationship, with a correlation coefficient (r²) of 0.9871. The ATP bioluminescence method indicated good reproducibility, and the results were stable and reliable. Conclusion This study further validates the applicability of ATP bioluminescence method for the quick detection of colonies number in chilled meat, demonstrating its advantages over the national standard plate count method.

Objective To systematically evaluate the differences in overall quality of rice from different regions in Liaoning Province. Methods Using 125 different rice varieties as research objects, the quality of rice from different regions in Liaoning Province was analyzed and comprehensively evaluated through physical and chemical testing methods, using correlation analysis (CA), principal component analysis (PCA), and hierarchical cluster analysis (HCA). Results The order of influence of different varieties and origins of rice on quality indicators was: Retention rate of germ grains>chalky grains rate>chalkiness>milled rice rate>brown rice rate>moisture> ash>protein>brown rice quality>fat>length-width ratio>fiber. Using stepwise regression analysis, the regression equation was obtained as follows: Brown rice rate=4.672×brown rice quality-0.104×chalky grains rate+0.141×chalkiness-0.860×length-width ratio-13.205. PCA extracted 4 principal components with a cumulative variance contribution rate of 80.046%, effectively elucidating all quality information characteristics. The results from HCA were consistent with those obtained from PCA, categorizing the 125 rice varieties into 3 major groups; through comprehensive assessment, the top 3 ranked varieties were identified as Yudao No.17 from Xiqing Village, Shiyuan Town, Dashiqiao City in Yingkou; Ichigo-hime from Zhangjia Village at Xinli Farm in Dawa County, Panjin; and Yanfeng No.47 from Gongxing Village in Tianshui Township, Panshan County, Panjin. Conclusion This study effectively highlights the differences in quality among various regional rices within Liaoning and provides a theoretical basis for breeding programs and product development related to rice germplasm.

Objective To establish a method for the simultaneous determination and risk assessment of multi-class pesticide residues in Cucumis sativus L. and Malus pumila Mill. using QuEChERS-liquid chromatography-tandem mass spectrometry. Methods Fruit and vegetable samples were homogenized using acetonitrile as extraction solvent, sodium chloride and anhydrous sodium acetate as salting-out agent, and the supernatant was taken and purified by primary secondary amines (PSA), graphitized carbon black (GCB) and anhydrous magnesium sulfate reagent, and 7 kinds of pesticides were analyzed in 11 min using an Agilent Poroshell 120 EC-C₁₈ column with gradient elution. The potential health risks associated with the consumption of Cucumis sativus L. and Malus pumila Mill. were assessed by calculating the estimated daily intake the estimated dietary intake (EDI) and hazard quotient (HQ). Results The 7 kinds of pesticides exhibited satisfactory linearity within the range of 5‒500 μg/L, with correlation coefficients more than 0.99. The limits of detection were 0.5‒1.0 μg/kg and the limits of quantification were 2.0‒4.0 μg/kg. The average recoveries ranged from 71.0% to 118.8% at three different spiked levels, with the relative standard deviations ranging from 3.1% to 12.7%. Concurrently, the HQ values of individual pesticides evaluated from the acceptable daily intake (ADI) were found to be less than 1, and their risks were within acceptable limits. Conclusion The method exhibits high accuracy, precision, and sensitivity, and is suitable for the simultaneous determination of multi-class pesticide residues in fruit and vegetable samples. Furthermore, the risk assessment results of this study demonstrated that the health risk to individuals from pesticide residues in Cucumis sativus L. and Malus pumila Mill. is within acceptable limits.

Objective To establish a method for the determination of chlorophyll a and chlorophyll b content in vegetables by convergence chromatography (CC). Methods The Soxhlet extraction method was used for efficient extraction of chlorophyll from vegetables and their products, followed by separation and detection using an ultra-performance convergence chromatography system coupled with a ultraviolet-visible detector. Results Through comparison of the stability of different solvents, petroleum ether was selected as the extraction solvent, and the extraction conditions were optimized. The method was validated with a limit of detection of 0.02 mg/kg, a limit of quantification of 0.06 mg/kg, a linear range of 0.06-800.00 mg/kg, a spike recovery rate of 99%-102%, and a relative standard deviation of 2.2%-14.0% for real samples. The reliability and accuracy of the method were confirmed through precision testing of real samples, including kale, fresh mustard greens, pickled mustard greens, dried pickled mustard greens, steamed dried pickled mustard greens, and boiled dried pickled mustard greens, as well as cross-validation with existing standard methods. Conclusion This study establishes a CC-based method for detecting chlorophyll a and chlorophyll b in vegetables, demonstrating high sensitivity, a wide linear range, good specificity, and precision. The method is not only suitable for laboratory research but also has practical application potential.