Water resources are an important foundation for Chinese national economy and social development, and water quality and environmental monitoring are of great significance for ensuring water resource security and water environment protection. Microbial detection technology, as a fast, accurate, and sensitive water quality monitoring method, has been widely applied in the field of water quality monitoring in China. In order to improve the effectiveness of microbial detection and enhance the monitoring of water quality and environment in China, this article will adopt literature review and practical research methods to analyze the commonly used microbial detection technologies and compare their advantages and disadvantages, aiming to provide scientific basis for water quality and environmental protection in China.

Grain and oil safety is related to the foundation of the safety of the entire food chain, and the testing of grain and oil institutions provides important technical support for government supervision. Quality control lies at the core of institutional testing, which not only ensures the accuracy and reliability of testing data, but also provides basic guarantee for establishing a scientific and sound testing system in testing institutions. This paper summarizes the main methods, monitoring links, and analyzes existing problems and challenges of quality control in grain and oil testing institutions. It proposes four suggestions for improving the further effectiveness of quality controlto provide reference for peers.

Objective Compare the performance differences of threeprotein content determination kits (Lowry method of Aimei, BCA method ofKangwei, and BCA method of Thermo Fisher) in detecting micro $\left({0 \sim {20\mu}\mathrm{g}/\mathrm{{mL}}}\right)$ protein. Select the mostaccurate and reliable reagent kit for the detection of trace proteinsamples. Methods Use these three test kits to detect micro proteincontent, compare their accuracy, sensitivity, linearity andrepeatability, and evaluate their equivalence. Results The recoveryrates of the three test kits for detecting trace amounts $\left({{1.25}\sim {20\mu}\mathrm{g}/\mathrm{{mL}}}\right)$ of protein were all withinthe range of 75%~120%, demonstrating qualified accuracy; Thermo FisherBCA meets the acceptable precision range (RSD $\leq 6\%$ ) in the range of ${2.5\mu }\mathrm{g}/\mathrm{{mL}}$ to ${20\mu }\mathrm{g}/\mathrm{{mL}}$ ,while Aimei Lowry and Kangwei BCA meet the acceptable precision range(RSD $\leq 6\%$ ) in the range of ${5\mu }\mathrm{g}/\mathrm{{mL}}$ to ${20\mu }\mathrm{g}/\mathrm{{mL}}$ ,demonstrating good repeatability; the correlation coefficient ${\mathrm{R}}^{2}$ of the standard curvesof the three test kits $\left({0\sim {20}\mathrm{{\mu g}}/\mathrm{{mL}}}\right)$ are all higherthan 0.980 . The linearity of Aimei Lowry is slightly poor, with ${\mathrm{R}}^{2}$ of 0.981 . The linearityof Kangwei BCA is qualified, with ${\mathrm{R}}^{2}$ of 0.991 . The linearityof Thermo Fisher BCA is the best, with ${\mathrm{R}}^{2}$ of 0.993; The abovemethodological validation results indicate that the minimumquantification limits for the sensitivity of the three test kits are ${5\mu }\mathrm{g}/\mathrm{{mL}}$ forthe Aimei Lowry method, ${5\mu}\mathrm{g}/\mathrm{{mL}}$ for the Kangwei BCA method, and ${2.5\mu }\mathrm{g}/\mathrm{{mL}}$ for theThermo Fisher BCA method, respectively; Paired curves of values detectedby three reagent kits for the same series of BSA concentrations andtheir correlation coefficients were all higher than 0.990 . ConclusionThrough experiments, we found that each reagent kit exhibited differentperformance in different concentrations of BSA samples, among which theThermo Fisher BCA method performed the best in terms of accuracy andrepeatability, and there was a certain correlation between these threemethods.

Objective To investigate and analyze the microbial contamination in the production and processing of pre-packaged sauced meat products in Sichuan Province. Methods The total number of bacterial colonies, coliform, Staphylococcus aureus, Listeria monocytogenes, Salmonella and Bacillus cereus were detected in 52 samples from a pre-packaged spiced meat factory in Sichuan province by national standard method. Results The results showed that the meat products were contaminated by Escherichia coli, Staphylococcus aureus, Bacillus cereus and Listeria monocytogenes during the curing process. The detection rate of microorganisms gradually decreased with the process of processing, and high temperature sterilization had a significant effect on reducing the microbial pollution of the final product; By tracing analysis, it was found that the environment and equipment in the raw and cooked area were contaminated by Listeria monocytogenes of the same serotype. Conclusion The factory has a big problem of staff hygiene, raw food area and cooked food area cross-contamination, it is recommended that enterprises strictly control the production environment and personnel hygiene, regular cleaning and disinfection, reduce the pollution of processing environment and equipment, workshop operators and food cross-contamination and raw and cooked food cross-contamination, in order to reduce the risk of product microbial contamination.

The high and low temperature test chamber can provide thecorresponding high and low temperature environment for instruments andmaterials, and its temperature field performance and measurementuncertainty are important indicators that affect the measurement resultsof the temperature test chamber. Through the uncertainty evaluation andinfluence analysis of temperature deviation calibration results, themeasurement performance of high and low temperature test chamber, errorsources and methods to reduce the influence of error are furtherunderstood. According to the calibration method specified in GB/T10592-2023 Technical Conditions for High and Low Temperature TestChamber, select the temperature sensor that meets the measurementrequirements and calibrate the temperature deviation of the high and lowtemperature test chamber. The calibration confirms that the temperaturefield performance of the high and low temperature test chamber meets thetolerance requirement of temperature deviation $\pm {2}^{\circ }\mathrm{C}$ , and themeasurement uncertainty meets the technical index requirement of $1/3$ maximum allowable error. Thetemperature field performance of the high-low test chamber is good, andthe short-branch A-class platinum thermal resistance selected by themeasurement standard meets the calibration requirements and has goodstability.

Objective This article mainly introduces three methods for measuring pitting depth: metallographic method, micrometer method and microscopy method, and discusses their differences in different pitting conditions and their influence on the measurement results. Methods Pitting pits on the surface of carbon steel and stainless steel were respectively measured by using these three measuring methods. and the measured results were analyzed and discussed. Results By comparing the measurement results, we can see that the metallographic method is more accurate, but it is destructive. The micrometer method is only suitable for wide and shallow pitting pits. The microscope method is not only suitable for wide and shallow pitting pits, but also for the small pit bottom. Conclusion (1) For wide and shallow pitting pits, metallographic method, micrometer method and microscopic method are applicable and the results are consistent; (2) For the small pitting pit at the bottom, metallography and microscopy are more suitable and the results are consistent; (3) When the corrosion depth is measured by metallographic, microscope and micrometer methods, the thickness reduction caused by uniform corrosion should be taken into account and the results should be corrected, especially in the case of more obvious uniform corrosion.

Objective To establish a spectrophotometric evaluationmethod for determining sulfur dioxide uncertainty in formaldehydeabsorption fluid. Methods According to JJF 1059-2012, Evaluation andrepresentation of measurement Uncertainty, establish a mathematicalmodel to calculate each uncertainty component and synthetic uncertainty. Results The uncertainty introduced by repeated measurement is 0.27%; thestandard curve preparation is 0.40%; the standard curve drawing andfitting is 0.20%; the instrument measurement is 0.35%; the syntheticrelative standard uncertainty is 0.63%, and the extended uncertainty is ${0.008}\mathrm{{mg}}/\mathrm{L}$ . Conclusion This method is suitable for measuring the uncertaintyassessment of sulfur dioxide in formaldehyde absorption fluid.

Objective To understand the sanitary condition of secondarywater supply in jinan railway area and provide scientific basis forrailway departments to improve secondary water supply. Methods Accordingto ( Standard test method for drinking water $\}$ , we sampled and tested the waterquality. On the basis of $《$ Hygienic specification for facilities of secondary water supply》, weanalyzed the data about engineering acceptance and daily detection waterquality. Results Daily detection of secondary water supply qualifiedrate was ${82.69}\%$ , higher thanengineering acceptance of secondary water supply qualified rate ${65.77}\%\left({P <{0.05}}\right)$ .Acoording to the daily detection qualified rate analysis of secondarywater supply, the qualified rate of water supply from living area,passenger station, well of the train track and train water tank wasdecreased successively. The difference of the qualification rate amongthe sampling locations is statistically significant $\left({P <{0.05}}\right)$ ; Thequalified rate in each month is all above ${74}\%$ . The qualified rate in March,April, June and September is below 80%.Soil microbial indicators anddisinfectant indicators qualified rate trend consistent with allindicators qualified rate trend. The qualified rate of ex-factory waterwas ${90.54}\%$ , which was higherthan ${81.19}\%$ of peripheral water $\left({P <{0.05}}\right)$ . Theunqualified soil microbial indicators and disinfectant indicators arethe main factors causing the unqualified secondary water supply. Conclusion The qualified rate of secondary water supply in jinan railwayarea is higher than other water supply types, but there are hiddendangers in the health situation. The supervision of secondary watersupply should have further strengthen.

Objective To investigate the distribution of hepatitis Bvirus (HBV) genotypes and drug resistance mutation sites in Kaifengarea. Methods A total of 200 hepatitis B surface antigen (HBsAg)positive patients were selected from Kaifeng area from January 2018 toDecember 2020. The genotype of the patients was detected by genesequencing technology, and the test results were statistically analyzed.Nucleoside analogues (NAs) resistance gene loci in serum HBV-DNA of 200untreated patients were analyzed. Results Among 200 HBsAg positivepatients in Kaifeng area, 179 cases were genotype C, accounting for ${97.8}\%,4$ cases were genotype B,accounting for ${2.2}\%$ , and no B+Cor other types were detected. Among the 200 patients, 26 were detectedNAs gene drug resistance mutation sites, and the detection rate of drugresistance mutation sites in patients with gene $\mathrm{C}$ was higher than that inpatients with gene B. Conclusion Hepatitis B surface antigen positivepatients in Kaifeng area of HBV genotype mainly $\mathrm{C}$ type, B type is less, no othergenotype was detected. The detection rate of NAs resistance sites ingenotype C was higher than that in genotype B. A total of 9 differentcombinations of NAs drug-resistant mutation sites were detected, mainlyunit point mutation.

Based Perchlorate is a new type of pollutant in drinkingwater, which is harmful to human health. The newly promulgated“Standards for Drinking Water Quality”(GB 5749-2022) has been listed asan expanded indicator. The uncertainty of determination of perchloratein drinking water by ion chromatography was evaluated, and the factorsaffecting the accuracy of the result were determined. On the StandardTest Method for Drinking Water Part 5: Inorganic Nonmetallic Indicators(GB/T 5750.5-2023), the perchlorate in drinking water was measured byion chromatography, and the uncertainty introduced in each step wasanalyzed and calculated. And evaluate its expanded uncertainty. Theperchlorate concentration in drinking water was ${0.101}\mathrm{{mg}}/\mathrm{L}$ and theextended uncertainty was ${0.005}\mathrm{{mg}}/\mathrm{L}\left({k =2}\right)$ . The measurement uncertainty is mainly introducedfrom six aspects, namely, the standard material itself, the preparationof standard working fluids, the preparation of series of standardworking fluids, the determination of sample repeatability, the recoveryrate and the main equipment. The most important factor affecting thetotal uncertainty is the uncertainty introduced in the preparationprocess of standard series working fluids.