Objective To investigate the formula optimization conditions for low-sugar tamarind-coconut oil fruit cake, utilizing tamarind, coconut oil and xylitol as the primary ingredients, and to assess the quality of the final product. Methods The low-sugar tamarind-coconut oil fruit cake was optimized using sensory evaluation, texture, and color difference as indicators through a single-factor orthogonal experimental design. The physical, microbial, mineral element, and flavor characteristics of the finished product were also analyzed. Results The optimal formulation for low-sugar tamarind-coconut fruit cake was: Based on a total product weight of 50 g, tamarind juice 8 g, coconut oil 4 g, carrageenan 0.27 g, konjac powder 0.54 g and xylitol 8 g. Under these optimal conditions, the sensory score of the low-sugar tamarind-coconut oil fruit cake was 94.70 points; the hardness, elasticity, adhesiveness and chewiness were 93.33 g, 2.54 mm, 79.33 g and 2.00 mJ, respectively; the color difference L^*, a^*, b^* were 46.34, 7.13, 13.27 respectively; the total sugar, total acid and amino acid content were 27.18 g/100 g, 0.39 mg/g and 0.25 mg/g, respectively; the content of mineral elements potassium, phosphorus, calcium, and magnesium were 717.95, 62.17, 73.70 and 91.40 mg/kg, respectively, with a ratio of phosphorus to calcium close to 1:1; electronic nose analysis reveals that the aroma of the finished product primarily consists of short-chain alkanes, alcohols, ethers, aldehydes, ketones, aromatic compounds, and sulfides. The sum of contribution rates of the first and second principal components in principal component analysis (PCA) was 98.80%. Conclusion The low-sugar tamarind-coconut oil fruit cake made by this method is nutritious, moderately soft and firm in texture, with uniform color and unique flavor.

Objective To evaluate the safety of a composite beverage made from Ganoderma leucocontextum fermented Pu-erh tea compound beverage. Methods Using the Ganoderma leucocontextum fermented Pu-erh tea compound beverage as the study subject, based on preliminary experiments and related research, the dose was set at 10000 mg/(kg·bw). The classical limit method was employed, with healthy ICR mice selected as the experimental model, and the test substance was administered via oral gavage. The experiment strictly adhered to animal ethics and welfare principles, with precise control of environmental conditions including temperature, humidity and light cycles to ensure the accuracy and reliability of the data. Results After administration of the test substance, no signs of toxicity were observed in any of the ICR mice throughout the observation period. Their behavioral activity remained normal, with glossy fur and vigorous spirits. Regular precise measurements of mouse body weight showed no significant abnormalities in growth trends, and no deaths occurred. Statistical analysis revealed that the acute oral toxicity median lethal dose (LD₅₀) values for both male and female ICR mice were greater than 10000 mg/(kg·bw), with 95% confidence intervals also exceeding 10000 mg/(kg·bw). Conclusion Based on international acute toxicity dose classification standards, the Ganoderma leucocontextum fermented Pu-erh tea compound beverage is classified as practically non-toxic. This indicates that under the experimental conditions of this study, the acute oral intake safety of this composite beverage is high, providing critical safety data support for subsequent product development and market promotion.

Objective To understand the residue status and exposure levels of 6 kinds of quinolone antibiotics in common freshwater fish and shrimp sold in Beijing. Methods The 90 freshwater fish and shrimp products from 40 supermarkets and farmers’ markets in 9 districts and counties of Beijing were randomly sampled for the determination of 6 kinds of quinolone antibiotics in fish and shrimp meat by liquid chromatography-tandem mass spectrometry. The exposure risk of quinolone antibiotic residues in fish and shrimp to residents of 10 gender/age groups was assessed by the index of food safety (IFS). Results The 4 kinds of quinolone antibiotics were detected in 90 fish and shrimp samples. The detection rate for pefloxacin, ofloxacin, enrofloxacin and ciprofloxacin were 1.11% (1/90), 1.11% (1/90), 26.67% (24/90) and 6.67% (6/90). There were excessive samples of pefloxacin, ofloxacin and enrofloxacin detected, with an exceedance rate of 1.11% (1/90), 1.11% (1/90) and 5.56% (5/90) respectively. Norfloxacin and lomefloxacin were not detected in all samples. The IFS of quinolone antibiotics ranged from 0.040-0.067 in the general-case scenario and from 0.170-0.283 in the worst-case scenario, which was much less than 1. Conclusion The detection of quinolone in freshwater fish and shrimp sold in Beijing is dominated by enrofloxacin and ciprofloxacin, and the health risk of 6 kinds of quinolone antibiotics to human beings is at a safe level in this study, which provides regional data support for the assessment of the quality of aquatic products and the revision of food safety standards.

Objective To establish and evaluate the application of direct mercury analysis for the determination of total mercury in food. Methods A direct mercury analysis method was developed based on catalytic pyrolysis-gold amalgamation atomic absorption spectroscopy. By stepwise optimization of pyrolysis temperatures (150 °C/550 °C for low-concentration ranges and 200 °C/650 °C for high-concentration ranges) and carrier gas flow rates (150-200 mL/min), plant-derived samples (e.g., rice, jujube), animal-derived samples (e.g., snakehead, fish meal), and 14 kinds of food samples were analyzed. The method’s detection limit, accuracy, stability and spike recovery were evaluated to assess its performance and matrix applicability. Results The method established dual linear calibration curves of 0-10 ng and 25-200 ng, with correlation coefficients of 0.9993 and 0.9998, respectively. The limit of detection and limit of quantitation were 0.0002 mg/kg and 0.0005 mg/kg, respectively. Spike recoveries ranged from 90% to 116%, the intra-day and inter-day repeatability relative standard deviation was less than or equal to 6.5% and less than or equal to 7.7%, respectively. The method was systematically validated for complex matrices, including plant-derived, animal-derived, and processed foods, with all results complying with the GB 2762-2022 National food safety standard-Limits of contaminants in foods. Conclusion The proposed method eliminates the need for chemical digestion in sample pretreatment, significantly shortens the analytical time, and prevents mercury volatilization losses. It overcomes the limitations of single-matrix analysis and achieves rapid total mercury detection in diverse complex food matrices, thereby providing an efficient and reliable technical solution for food safety risk monitoring and regulatory compliance.

Objective To compare the resistance differences of 18 kinds of bacterial strains and 2 kinds of biological indicators to chlorine-containing disinfectants, hydrogen peroxide and quaternary ammonium compounds. Methods Strains were selected from food, environment and human sources, including gram-negative bacteria, gram-positive bacteria and spore-forming bacteria (6 kinds of strains per category). Species identification was performed using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) and biochemical assays. The 2 kinds of biological indicators, namely Staphylococcus aureus ATCC6538 and Escherichia coli 8099 were used as reference strains. Bacterial suspensions (2.0×10⁸-10.0×10⁸ CFU/mL) were prepared to test their tolerance to sodium hypochlorite (available chlorine 0.00400%-0.00499%), hydrogen peroxide (7.5%), and benzalkonium bromide (3.996 mg/mL). All bacterial strains were treated with disinfectants for 3 minutes. By calculating the killing log value (KL) of disinfectants against different bacterial strains, the differences in resistance of different species of bacterial strains to 3 kinds of disinfectants were compared. Results The bactericidal efficacy ranked as sodium hypochlorite, hydrogen peroxide, benzalkonium bromide. Different species showed significant variations in resistance to disinfectants. Among 3 categories of bacterial strains (gram-negative bacteria, gram-positive bacteria and spore-forming bacteria), there were strains within each category that exhibit higher resistance to disinfectants than 2 kinds of biological indicators. Conclusion Sodium hypochlorite and hydrogen peroxide exhibit superior bactericidal effects compared to benzalkonium bromide. The resistance to disinfectant of bacteria is species-specific and cannot be predicted solely by gram classification. The screening scope for biological indicators should be expanded based on actual needs.

Objective To assess the dietary exposure risk of mycotoxins for Beijing consumers, based on the mycotoxins contamination data during the cold storage period of Castanea mollissima which harvested in Huairou District, Beijing. Methods Castanea mollissima samples were collected from the 4 highest yielding townships in Huairou District. Samples were stored in a cold storage for 1 year and sampled once a month to determine the content of 21 kinds of fungal toxins. Based on the 2002 Beijing residents’ dietary consumption survey data, point estimation method, probability method and cumulative risk assessment modeling method of multiple fungal toxins were used to evaluate the acute and chronic dietary exposure risks of different genders of consumers. Results The estimated daily intake levels of alternariol and alternariol monomethyl ether in some Castanea mollissima samples were higher than 2.5 ng·kg^-1·bw·d^-1. The estimated daily intake levels of tentoxin and tenuzonic acid in all samples during the entire storage period did not exceed 1500 ng·kg^-1·bw·d^-1. The estimated daily intake/tolerable daily intak of nivalenol, fumonisin B₁, total fumonisin and zearalenone were all less than 100. The margin of exposure (MOE) was used to analyze the sterigmatocystin, and the result was greater than 10000. The 2 kinds of different chronic effects were analyzed for ochratoxin A. The cumulative risk assessment of mycotoxins in Castanea mollissima samples showed that some samples had MOE below 100 after storage for about 10 months. Conclusion All varieties of Castanea mollissima samples are no significant risk of mycotoxins to consumers after stored for 9 months in cold storage, and consumers can safely eat them. But multiple mycotoxins are detected simultaneously during the late stage of storage, which may pose health risks to humans. In order to clarify these health risks further, more toxicological data is needed.

Objective To establish a method for the determination of 9 kinds of pesticide residues in black tea and green tea based on multi-walled carbon nanotubes (MWCNTs) combined with gas chromatography-tandem mass spectrometry (GC-MS/MS). Methods The key parameters were optimized by single factor experiment, including the amount of MWCNTs, ultrasonic extraction time and extraction solvent, and the methodological performance was evaluated, including linear range, detection limit, quantification limit, accuracy and precision. Results The linear relationship of this method was excellent, with correlation coefficients all greater than 0.99. The limits of detection and limits of quantitation were 0.002-0.004 mg/kg and 0.007-0.012 mg/kg, respectively. The recoveries of 9 kinds of pesticides in black tea and green tea were 71.52%-118.80%, and the relative standard deviation were 1.00%-6.92%. Conclusion This study successfully establishes a pesticide residue detection method based on MWCNTs combined with GC-MS/MS, which has the advantages of high sensitivity, high recovery rate and low solvent consumption, and significantly improves the detection efficiency. The actual sample detection shows that this method is suitable for the rapid screening of commercially available tea, and provides reliable technical support for the regulatory authorities.

Objective To establish a method for simultaneous determination of 23 kinds of per-and polyfluoroalkyl substances (PFASs) in food by high efficiency reinforced fat removal bilayer column-ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Methods The sample was extracted and centrifuged, high efficiency reinforced fat removal bilayer column method was adopted for the purification, the sample solution was separated on an Shim-pack GISS Hp 3 μm C₁₈ column using 2 mmol/L ammonium formate and methanol as mobile phase for gradient elution, detected by tandem mass spectrometry with multiple reactions monitoring (MRM), and quantified by internal standard method. Results The 23 kinds of target compounds of PFASs were well retained on the chromatographic column with good linearity in the range of 0.2-50.0 µg/L (r²>0.995). The limits of detection (LODs) and the limits of quantitation (LOQs) about perfluorobutanoic acid (PFBA) and perfluoropentanoic acid (PFPeA) were 0.06 μg/kg and 0.18 μg/kg respectively. LODs and LOQs about the remaining 21 kinds of perfluorinated compounds were 0.03 μg/kg and 0.09 μg/kg, respectively. The recoveries of the 23 kinds of target compounds of 2.0 μg/kg and 10.0 μg/kg spiked levels in the meat, fish and milk matrix ranged from 70.3%-120.0% with relative standard deviations of 1.56%-9.65%. Conclusion This method is easy, fast, accurate and sensitive, which is suitable for the determination of 23 kinds of PFASs in food.

Objective To study the changes of acid value, benzo [a] pyrene, 4 kinds of polycyclic aromatic hydrocarbons (PAH4) and 16 kinds of polycyclic aromatic hydrocarbons (PAH16) content in frying french fries soybean oil/peanut oil at different temperatures and times. Methods The acid value in oils was titrated by anhydrous ether:isopropanol (1:1, V:V) using phenolphthalein as an indicator. The polycyclic aromatic hydrocarbons in samples were saponified by KOH/ethanol, extracted with n-hexane and cleaned-up by solid-phase extraction column, detected by gas chromatography-mass spectrometer. Results With the increase of frying temperature and time, the acid value increased rapidly, and the changes in peanut oil were more sensitive. At the same temperature, both benzo [a] pyrene and PAH4 showed an irregular fluctuating growth with time, and the higher the temperature, the faster the increase. The content of PAH16 rapidly increased with time and temperature, and its changes were more sensitive than those of benzo [a] pyrene and PAH4. Under the same conditions, the increase of benzo [a] pyrene, PAH4 and PAH16 in peanut oil was less than that in soybean oil. Conclusion At the same conditions, PAH16 shows more significant changes compared to benzo [a] pyrene and PAH4, so the limits of PAH16 should be given more attention.

Objective To detect and analyze the content of mineral elements in wines of different varieties and years from the Helan Mountain East Slope region, and construct a model for identifying wine varieties and years based on mineral elements using multivariate statistical analysis methods. Methods Grapes of 5 varieties, namely, Zinfandel, Merlot, Malbec, Cabernet Sauvignon and Marselan, were collected from a winery in Qingtongxia, Ningxia, and were processed into wines using the same method. Wines of the Cabernet Sauvignon variety from 6 years (2018—2023) were collected from a winery in Yongning, Ningxia. The content of 54 kinds of mineral elements including B, Bi, Be, etc. in the wines was determined by inductively coupled plasma mass spectrometry. A model for identifying wine varieties and years was constructed based on the differences in mineral element content among different varieties and years of wines. Results A total of 53 mineral elements were detected in wines of different varieties, and 47 kinds of mineral elements including As and B showed extremely significant differences among varieties (P<0.01). All 54 kinds of mineral elements were detected in wines of different years, and all showed extremely significant differences among years (P<0.01). The correct discrimination rate of the model for identifying wine varieties and years based on Fisher discriminant analysis was 100%. The 9 kinds of mineral elements, namely, As, Cs, Dy, Mo, Na, Sb, U, Yb and Fe, were identified as the differential elements for different varieties of wines, and 11 kinds of mineral elements, namely, Cu, Li, Na, Sb, Tl, U, V, Y, Yb, Ag and Pt, were identified as the differential elements for wines of the same variety from different years. The correct discrimination of wines from the same origin but of different varieties and years was achieved based on mineral elements. Conclusion Mineral elements show significant differences among wines of different varieties and years, and can be used for the identification of wine varieties and years from the same region.