Objective To study on the improvement of incubation time and plate load capacity for molds enumeration. Methods Mold quality control samples were tested according to GB 4789.15—2016 National food safety standard-Food microbiological examination-Enumeration of moulds and yeasts, with additional colony counting performed on the second day of incubation. The plate size was increased from 90 mm to 150 mm, and statistical analysis was employed to assess the differences between colony counts and the reference value of the quality control samples. Results Significant discrepancies were observed between the fifth-day counting result at the critical dilution (1:10) and the reference value. A sharp decline in colony counts was noted when the colony-forming units exceeded 30 CFU per 90 mm plate, which was defined in this study as the maximum load capacity of mold plates under acceptable accuracy. By adopting 150 mm plates with a 2-day incubation period, the original load capacity was overcome, yielding counting results that aligned well with the reference value. Under these optimized conditions, the linear coefficient of determination (R²) between sample means and dilution factors improved from R²₉₀=0.614 to R²₁₅₀=0.998. Conclusion The optimized testing conditions effectively addressed the issues of colony overgrowth and poor linearity in mold plate count experiments, thereby enhancing the accuracy of test results.

Objective To investigate the distribution of 26 kinds of metal elements (Pb, Cd, Hg, As, Cr, Al, Mn, Cu, Ba, V, Se, Sb, Ni, Sn, Li, B, Zn, K, Na, Ca, Mg, Fe, Sr, Mo, Co, Rb) and assess the dietary risk with cereals in Handan City. Methods A total of 51 cereal samples (wheat and maize) were analyzed for 26 kinds of metal elements using inductively coupled plasma mass spectrometry (ICP-MS). Statistical analysis was performed on the detection results, and nutritional and exposure risk assessments were conducted for macro- and trace elements using the individual pollution index, target hazard quotient, carcinogenic risk, and estimated daily intake. Results The method demonstrated good linearity, high accuracy, and sensitivity. Among the 26 kinds of metal elements, 24 kinds of metal elements were detected in the cereal samples, except for Hg and Li. Principal component analysis and correlation analysis revealed interspecies differences between wheat and maize, as well as distinct correlations among different elements. The contamination levels of 5 kinds of heavy metals (Pb, Cd, Hg, As, Cr) were within safe limits. The target hazard index of 19 kinds of metal elements and the carcinogenic risk index for Pb were significantly below threshold levels, indicating no health risks, but the carcinogenic risk assessment for As suggested potential health risks. Nutritional assessment showed that the cereals were rich in K and Mg, but low in Na. However, Cr exposure reached nearly 300% of the adequate daily intake, indicating a significant health concern. Conclusion The established method is effective for multi-element analysis in cereals. This research findings provide updated dietary intake assessment of multi-elements of Handan adult consumers. The dietary assessment indicates that intake of cereals in Handan City poses no significant health risks, but particular attention should be paid to Cr and As contamination.

Objective To establish a method for the determination of 9 kinds of organic acids (oxalic acid, tartaric acid, quinic acid, malic acid, lactic acid, citric acid, fumaric acid, succinic acid and gallic acid) in fruits and vegetable crisps by liquid chromatography-high resolution mass spectrometry (LC-HRMS). Methods The samples were cleaned up by a SAX solid-phase extraction column. The samples were eluted with 0.1% formic acid in water and methanol as mobile phases and separated on an Eclipse Plus C₁₈ column (4.6 mm×250 mm, 5 μm), and monitored in electron spray ionization (ESI)- mode and quantified by external standard method. Results The calibration curves for 9 kinds of organic acids showed good linearity in the concentration range of 50-5000 ng/mL. The correlation coefficients (r) were all greater than 0.9991, the limits of detection (LODs) were in the range of 1-10 ng/mL, the limits of quantitation (LOQs) were in the range of 10-50 ng/mL, the spiked recoveries were in the range of 96%-98%, and the relative standard deviations (RSDs) were in the range of 1.5%-4.9%. Among them, lactic acid [(16.16±0.30) mg/g] and citric acid [(15.53±0.11) mg/g] were the main organic acids in the fruit and vegetable crisps, and their content was significantly higher than those of other organic acids. In contrast, tartaric acid [(1.29±0.11) mg/g] and oxalic acid [(1.56±0.25) mg/g] were found at lower levels. Conclusion The method is simple, rapid, and accurate and can be used for the qualitative and quantitative determination of organic acids (oxalic acid, tartaric acid, quinic acid, malic acid, lactic acid, citric acid, fumaric acid, succinic acid and gallic acid) in fruit and vegetable crumbles as well as other food.

Objective To assess the risks of pesticide residues of animal-derived foods in commercial market. Methods The 146 kinds of pesticides were determined in 460 batches of animal foods by gas chromatography-tandem mass spectrometry. The risk of pesticide residues detected in animal foods was evaluated by food safety index (IFS) method and dietary risk assessment model. Results The overall detection rate of the sample was 48.9%, and a total of 24 kinds of pesticides were detected, primarily insecticides, with low and moderate toxicity being the main characteristic. Among the detected samples, the number of detected pesticides was the highest in aquatic products, followed by eggs, livestock meat and poultry meat. Among the detected pesticides, the largest number of pesticides were detected in aquatic products, followed by livestock meat, poultry meat and eggs. The pesticides in aquatic products were mostly hexaflumuron, pendimethalin, DDT, dimethoate, trifluralin, thifluzamide and carbaryl. While the livestock meat was mainly diphenylamine, ethoprophos and boscalid, the poultry was mainly boscalid, and the eggs were mainly fipronil. The results of IFS showed that the average safety index ($\overline{\text{IFS}}$) of all pesticides was 0.000001-0.010021, which was far less than 1. The overall safety status of all pesticides in animal foods was acceptable. The results of dietary risk assessment indicated that acceptable daily intake (%ADI) of each detected pesticide in the 4 types of animal-derived foods were far less than 100%, and the hazard quotient (HQ) and hazard index (HI) were far less than 1. The risk level of these pesticide residues of animal foods was within the acceptable range. Conclusion There are pesticide residues in animal-derived foods. Although the overall risk of pesticide residues detected in animal-derived foods is relatively low and within an acceptable range, however, samples and pesticides with high detection rates should be the focus of supervision to ensure the safety of animal-derived foods in the future.

As the world's largest producer and consumer of meat products, its consumption structure, industry development and food safety issues significantly shape both its domestic consumer market and global trade patterns. The increase in per capita disposable income of Chinese residents has promoted the diversified development of the consumption structure of meat and meat products, the progress of food technology and industry system has promoted the development of the industry towards product diversification, technological perfection and process systematization, and gradually formed a standard system pattern with mandatory standard system as the core and recommended standard system as the main body. Although China's meat and meat products industry has developed for many years with a relatively complete standard system and industrial pattern, there are still problems such as insufficient coordination of standards and lagging revision and review cycles. The diversification of consumption and industrial structure has led to increasingly prominent food safety issues. This review systematically summarized the urban and rural consumption characteristics of meat and meat products in China, as well as their standard system and industry development. It comprehensively analyzed the risks of the entire chain of meat and meat products from breeding to processing, and proposed suggestions for the problems existing in their development process to promote the healthy and stable development of China's meat and meat products industry.

Objective To establish a method for the determination of 5 kinds of drugs (atropine, procaine, scopolamine, anisodamine and lidocaine) in lard and pork by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Methods The pretreatment conditions and instrument parameters were optimized. HLB Pro solid-phase extraction cartridges were used for purification, with 1 mL of 30% acetonitrile and 1 mL of pure acetonitrile for elution. The residues of the 5 kinds of veterinary drugs in lard and pork were determined under the following conditions: 5 kV capillary voltage, 540 °C desolvation gas temperature at 13 L/min, 2 L/min nebulizer gas flow, 1.2 L/min cone gas flow, and multiple reaction monitoring mode. Results The calibration curves of the 5 kinds of drugs showed good linearity in the mass concentration range of 0.1-10.0 ng/mL, with correlation coefficient (r²)>0.9950. The limits of quantitation ranged from 0.013 to 0.142 µg/kg. Recoveries were between 84.72% and 106.24%, and precision (n=6) ranged from 0.45% to 7.32%. No target drug residues were detected in the tested pork and lard samples. Conclusion This study establishes a detection method based on a domestically produced LC-MS/MS system and HLB Pro solid-phase extraction columns, providing a cost-effective and reliable solution for the efficient screening of the 5 kinds of veterinary drug residues in pork and lard.

Objective To investigate the differences in mineral element content between sole fish and basa fish and establish an authenticity identification method. Methods Inductively coupled plasma mass spectrometry were employed to determine 25 kinds of mineral elements in 29 sole fish samples and 24 basa fish samples. Principal component analysis were performed using SPSS 25.0 software on the measurement results, and comparative analysis were conducted on mineral element contents among 3 kinds of different genera of sole fish. Results The total mineral element content in sole fish were significantly higher than that in basa fish. Na, K and Ca were identified as the primary mineral elements in both species, with Sr, As, Mn, Fe and Zn serving as secondary elements. Notably, Sr, As, Mn and Fe were detected exclusively in sole fish but absent in basa fish. Significant differences were observed in 9 kinds of elements: Mg, Ti, Zn, As, K, Ca, Na, Mn, and Fe. Principal components of sole fish within the same genus exhibited relative clustering, with marked differences in 7 kinds of elements: V, Mn, B, Ba, Fe, As and Sr. Conclusion Mineral element analysis can effectively distinguish sole fish from basa fish for authenticity verification.

Objective To explore the effects of ultrasonic synergistic enzymatic hydrolysis on the antioxidant activity and structure of donkey milk casein, optimize the process parameters of composite treatment, and analyze the promotion mechanism of ultrasonic pretreatment on the enzymatic hydrolysis process. Methods Using donkey milk casein as raw material, the ultrasonic parameters (200 W, 20 min, 6 s/6 s intermittency ratio) were optimized by single factor experiment, the neutral protease and trypsin (the mass ratio was 2:1) were screened, and the enzymatic hydrolysis conditions were optimized by response surface method (enzyme addition amount 4.86%, 55.28 °C, pH 7.76). The changes of protein molecular weight, secondary structure and functional groups were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and infrared spectroscopy. The antioxidant indexes such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging rate were determined. Results Ultrasonic synergistic enzymatic hydrolysis resulted in antioxidant ability of 69.77% and a 65.3% increase in Fe³⁺ reducing capacity, which was significantly better than that of the single treatment. The structure showed that the α-helix decreased to 26.70%, the random coil increased to 28.35%, the aromatic amino acids were exposed, the sulfhydryl groups were oxidized to disulfide bonds, and the molecular weight was reduced. The predicted value of the response surface model was in good agreement with the measured value (R²=0.9937). Conclusion The results of ultrasonic pretreatment significantly improves the antioxidant activity by destroying the structure of protein micelles and releasing antioxidant short peptides in synergy with enzymes, which provides a reference process parameter for the production of high value-added donkey milk antioxidant products, which is helpful to promote the development of donkey milk industry and improve the economic value of donkey milk.

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.