Rapid and Accurate Quantification of Viable Lactobacillus Cells in Infant Formula by Flow Cytometry Combined with Propidium Monoazide and Signal-Enhanced Fluorescence In Situ Hybridization.

Lactobacillus is an important member of the probiotic bacterial family for regulating human intestinal microflora and preserving its normalcy, and it has been widely used in infant formula. An appropriate and feasible method to quantify viable Lactobacilli cells is urgently required to evaluate the quality of probiotic-fortified infant formula. This study presents a rapid and accurate method to count viable Lactobacilli cells in infant formula using flow cytometry (FCM). First, Lactobacillus cells were specifically and rapidly stained by oligonucleotide probes based on a signal-enhanced fluorescence in situ hybridization (SEFISH) technique. A DNA-binding fluorescent probe, propidium monoazide (PMA), was then used to accurately recognize viable Lactobacillus cells. The entire process of this newly developed PMA-SEFISH-FCM method was accomplished within 2.5 h, which included pretreatment, dual staining, and FCM analysis; thus, this method showed considerably shorter time-to-results than other rapid methods. This method also demonstrated a good linear correlation (R2 = 0.9994) with the traditional plate-based method with a bacterial recovery rate of 91.24%. To the best of our knowledge, the present study is the first report of FCM combined with PMA and FISH for the specific detection of viable bacterial cells.

Rapid and accurate quantification of viable Bifidobacterium cells in milk powder with a propidium monoazide-antibiotic fluorescence in situ hybridization-flow cytometry method.

Due to its beneficial effects on human health, Bifidobacterium is commonly added to milk powder. Accurate quantification of viable Bifidobacterium is essential for assessing the therapeutic efficacy of milk powder. In this study, we introduced a novel propidium monoazide (PMA)-antibiotic fluorescence in situ hybridization (AFISH)-flow cytometry (FC) method to rapidly and accurately quantify viable Bifidobacterium cells in milk powder. Briefly, Bifidobacterium cells were treated with chloramphenicol (CM) to increase their rRNA content, followed by staining with RNA-binding oligonucleotide probes, based on the AFISH technique. Then, the DNA-binding dye PMA was used to differentiate between viable and nonviable cells. The PMA-AFISH-FC method, including sample pretreatment, CM treatment, dual staining, and FC analysis, required approximately 2 h and was found to be better than the current methods. This is the first study to implement FC combined with PMA and an oligonucleotide probe for detecting Bifidobacterium.

Soil urease functional stability to Hg pollution: An ecotoxicological perspective.

Mercury (Hg) is a persistent soil pollutant, and its toxicity can be evaluated using soil enzyme indicators. However, a thorough understanding of how the enzyme resists and remains resilient to Hg stress is essential, as it significantly impacts the accuracy of toxicity assessments. Therefore, it is worthwhile to understand the functional stability of urease in soil under Hg pollution. This study compares the effects of Hg at different concentrations and exposure times on soil urease. Results indicate that soil urease activity was enhanced in the first two hours under low levels of Hg pollution, decreased after six hours of acute Hg pollution, and reached its maximum reduction in 24 hours. The urease in fluvo-aquic soil, with higher soil organic matter showed higher resistance to Hg acute pollution than that in red soil. Over a longer aging process, soil urease activity gradually recovered with time. Hormesis effects were observed in red soil under high Hg stress after 30 days, showing the strong resilience of urease enzyme function to Hg pollution. The ecological dose, ED10, (the Hg concentration causing a 10% reduction in soil urease activity) ranged from 0.09 to 0.59 mg kg-1 under short-term exposure, and was lower than that under a longer aging process (0.28 to 2.71 mg kg-1). Further, aging reduced the Hg ecotoxicity due to decreased Hg availability and the resilience of soil urease activity. This indicates that the risk of Hg pollution estimated by soil urease as an indicator depends on exposure time and enzyme stability. These factors need consideration in heavy metal pollution assessments using soil enzymes.

Silencing P25, HC-Pro and Brp1 of Potato Virus (Viroid) Using Artificial microRNA Confers Resistance to PVX, PVY and PSTVd in Transgenic Potato.

Virus infection is the key constraint to potato cultivation worldwide. Especially, coinfection by multiple viruses could exacerbate the yield loss. Transgenic plants expressing artificial microRNAs (amiRNAs) have been shown to confer specific resistance to viruses. In this study, three amiRNAs containing Arabidopsis miR159 as a backbone, expressing genes targeting P25, HC-Pro and Brp1 of potato virus X (PVX), potato virus Y (PVY) and potato spindle tuber viroid (PSTVd), were constructed. amiR-159P25, amiR-159HCPro and amiR-159Brp1 were cloned into the plant expression vector pCAMBIA1301 with a CaMV35S promoter, producing the p1301-pre-amiRP25-HCPro-Brp1 vector. Twenty-three transgenic plants (Solanum tuberosum cv. 'Youjin') were obtained by Agrobacterium tumefaciens-mediated transformation, and ten PCR-positive transplants were chosen for further analysis. Quantitative real-time PCR results indicated that 10 transgenic plants could express amiRNAs successfully. Southern blotting hybridization proved that amiR-159P25-HCPro-Brp1 had integrated into potato genome in transgenic lines. Viral (viroid) challenge assays revealed that these transgenic plants demonstrated resistance against PVX, PVY and PSTVd coinfection simultaneously, whereas the untransformed controls developed severe symptoms. This study demonstrates a novel amiRNA-based mechanism that may have the potential to develop multiple viral resistance strategies in potato.

Positively Charged Microplastics Induce Strong Lettuce Stress Responses from Physiological, Transcriptomic, and Metabolomic Perspectives.

Microplastics (MPs) can enter plants through the foliar pathway and are potential hazards to ecosystems and human health. However, studies related to the molecular mechanisms underlying the impact of foliar exposure to differently charged MPs to leafy vegetables are limited. Because the surfaces of MPs in the environment are often charged, we explored the uptake pathways, accumulation concentration of MPs, physiological responses, and molecular mechanisms of lettuce foliarly exposed to MPs carrying positive (MP+) and negative charges (MP-). MPs largely accumulated in the lettuce leaves, and stomatal uptake and cuticle entry could be the main pathways for MPs to get inside lettuce leaves. More MP+ entered lettuce leaves and induced physiological, transcriptomic, and metabolomic changes, including a decrease in biomass and photosynthetic pigments, an increase in reactive oxygen species and antioxidant activities, a differential expression of genes, and a change of metabolite profiles. In particular, MP+ caused the upregulation of circadian rhythm-related genes, and this may play a major role in the greater physiological toxicity of MP+ to lettuce, compared to MP-. These findings provide direct evidence that MPs can enter plant leaves following foliar exposure and a molecular-scale perspective on the response of leafy vegetables to differently charged MPs.

Rapid and Multiplexed Detection of Single Cells of Salmonella, Escherichia coli O157, and Shigella flexneri in Ground Beef by Flow Cytometry.

Salmonella, Escherichia coli O157, and Shigella flexneri are typical foodborne pathogens in ground beef, which can cause severe infection even when present as a single cell. Flow cytometry (FCM) methods are widely applied in the rapid detection of pathogens in food products. In this study, we report an FCM-based method for detecting single cells of Salmonella, E. coli O157, and S. flexneri in 25 g ground beef samples. We fluorescently labeled specific antibodies that could effectively identify bacterial cells, prepared single-cell samples by serial dilution, and optimized the pre-enrichment time. The results showed that 7 h of pre-enrichment is appropriate for sensitive single-cell detection by FCM. Finally, we evaluated this method in artificially contaminated and retail beef samples. This study outlines a novel highly sensitive FCM-based method to detect Salmonella, E. coli O157, and S. flexneri in beef samples within 8 h that can be applied to the rapid and multiplexed detection of foodborne pathogens.

Rapid Detection of Single Viable Escherichia coli O157 Cells in Fresh Lettuce and Strawberry by Immunomagnetic Flow Cytometry in Combination with Pre-Enrichment.

Enterohemorrhagic Escherichia coli are an important pathogen causing food poisoning. The rapid detection of viable E. coli O157 in vegetables and fruits at single-cell level is critical because of the low infective dose of this pathogen. In this study, an immunomagnetic flow cytometry (IMFC)-based method was developed to detect E. coli O157 in lettuce and strawberries inoculated with 1 CFU/25 g. This method developed immunomagnetic (IM)-beads to capture E. coli O157 cells. The pre-enrichment of E. coli O157 and IM-bead separation rapidly increased the concentration of cells to a detectable range for flow cytometry. Compared with the plate-based method, the diagnostic sensitivity and specificity of the IMFC-based method were 100% in 166 samples, including 100 artificially contaminated samples, 60 retail samples, and six O157-positive samples for proficiency testing. The developed IMFC-based method was found to be effective in detecting E. coli O157 at single-cell level in 25 g of lettuce or strawberry with relatively shorter associated time to results of 5.7 h. Therefore, the IMFC-based method could improve detection efficiency and also make early warnings in a short time.

Risk Assessment of Agricultural Plastic Films Based on Release Kinetics of Phthalate Acid Esters.

Plastic films have become an integral part of fruit and vegetable production systems, but their release of phthalate acid esters (PAEs) is a threat to human health. The release kinetics of PAEs and measures of risk are still not well understood. We investigated 50 agricultural films, with concentrations ranging from 2.59 to 282,000 mg kg-1. The seven commercially available film types included were polyvinylchloride (PVC), metallocene polyethylene (mPE), ethylene vinyl acetate (EVA), polyolefin (PO), and three mulch films. Bis(2-ethylhexyl) phthalate (DEHP) was detected in most of films, and its release fitted well into the first-order kinetic model. The release rate of DEHP was negatively related to the film thickness. The potential carcinogenic risks of DEHP in the air of six kinds of plastic greenhouses to human health were estimated. We found that the carcinogenic risks associated with PVC and mPE greenhouse films warrant greater attention. Though EVA, PO greenhouse, and mulch films were lower risk, we advise keeping plastic greenhouses well ventilated during the first month of use to reduce direct human exposure to volatile PAEs.

Strategy for Mitigating Antibiotic Resistance by Biochar and Hyperaccumulators in Cadmium and Oxytetracycline Co-contaminated Soil.

The global prevalence of antibiotic resistance genes (ARGs) is of increasing concern as a serious threat to ecological security and human health. Irrigation with sewage and farmland application of manure or biosolids in agricultural practices introduce substantial selective agents such as antibiotics and toxic metals, aggravating the transfer of ARGs from the soil environment to humans via the food chain. To address this issue, a hyperaccumulator (Sedum plumbizincicola) combined with biochar amendment was first used to investigate the mitigation of the prevalence of ARGs in cadmium and oxytetracycline co-contaminated soil by conducting a pot experiment. The addition of biochar affected the distribution of ARGs in soil and plants differently by enhancing their prevalence in the soil but restraining transmission from the soil to S. plumbizincicola. The planting of S. plumbizincicola resulted in an increase in ARGs in the soil environment. A structural equation model illustrated that mobile genetic elements played a dominant role in shaping the profile of ARGs. Taken together, these findings provide a practical understanding for mitigating the prevalence of ARGs in this soil system with complex contamination and can have profound significance for agricultural management in regard to ARG dissemination control.

Faster Detection of Staphylococcus aureus in Milk and Milk Powder by Flow Cytometry.

A flow cytometry (FCM)-based method was developed for the faster detection of Staphylococcus aureus in milk and milk powder. Viable S. aureus cells were recognized by highly selective, fluorescently labeled antibodies and Propidium Iodide, and then analyzed by FCM. Using a 5-h pre-enrichment period, the method could detect low numbers of S. aureus cells in 6 h, with a limit of detection of 7.50 cells/mL in milk and 8.30 cells/g in milk powder. The established method was compared with the plate-based method using 75 ultra-high-temperature-treated milk samples, 25 pasteurized milk samples, 66 raw milk samples, and 123 milk powder samples. The two methods yielded similar results for the detection of the pathogen in all sample types. The FCM-based method allows effective and faster monitoring of S. aureus contamination and can be applied to the rapid detection of microorganisms in milk and dairy products.

Soil enzyme kinetics indicate ecotoxicity of long-term arsenic pollution in the soil at field scale.

Information on the kinetic characteristics of soil enzymes under long-term arsenic (As) pollution in field soils is scarce. We investigated Michaelis-Menten kinetic properties of four soil enzymes including ß-glucosidase (BG), acid phosphatase (ACP), alkaline phosphatase (ALP), and dehydrogenase (DHA) in field soils contaminated by As resulting from long-term realgar mining activity. The kinetic parameters, namely the maximum reaction velocity (Vmax), enzyme-substrate affinity (Km) and catalytic efficiency (Vmax/Km) were calculated. Results revealed that the enzyme kinetic characteristics varied in soils and were significantly influenced by total nitrogen (N) and total As, which explained 31.8% and 30.7% of the variance in enzyme kinetics respectively. Enzyme pools (Vmax) and catalytic efficiency (Vmax/Km) of BG, ACP and DHA decreased with elevated As pollution, while the enzyme affinity for substrate (Km) was less affected. Redundancy analysis and stepwise regression suggested that the adverse influence of As on enzyme kinetics may offset or weakened by soil total N and soil organic matter (SOM). Concentration-response fitting revealed that the specific kinetic parameters expressed as the absolute enzyme kinetic parameters multiplied by normalized soil total N and SOM were more relevant than the absolute ones to soil total As. The arsenic ecological dose values that cause 10% decrease (ED10) in the specific enzyme kinetics were 20-49 mg kg-1, with a mean value of 35 mg kg-1, indicating a practical range of threshold for As contamination at field level. This study concluded that soil enzymes exhibited functional adaptation to long-term As stress mainly through the reduction of enzyme pools (Vmax) or maintenance of enzyme-substrate affinity (Km). Further, this study demonstrates that the specific enzyme kinetics are the better indicators of As ecotoxicity at field-scale compared with the absolute enzyme parameters.

Soil properties influence kinetics of soil acid phosphatase in response to arsenic toxicity.

Soil phosphatase, which plays an important role in phosphorus cycling, is strongly inhibited by Arsenic (As). However, the inhibition mechanism in kinetics is not adequately investigated. In this study, we investigated the kinetic characteristics of soil acid phosphatase (ACP) in 14 soils with varied properties, and also explored how kinetic properties of soil ACP changed with different spiked As concentrations. The results showed that the Michaelis constant (Km) and maximum reaction velocity (Vmax) values of soil ACP ranged from 1.18 to 3.77mM and 0.025-0.133mMh-1 in uncontaminated soils. The kinetic parameters of soil ACP in different soils changed differently with As contamination. The Km remained unchanged and Vmax decreased with increase of As concentration in most acid and neutral soils, indicating a noncompetitive inhibition mechanism. However, in alkaline soils, the Km increased linearly and Vmax decreased with increase of As concentration, indicating a mixed inhibition mechanism that include competitive and noncompetitive. The competitive inhibition constant (Kic) and noncompetitive inhibition constant (Kiu) varied among soils and ranged from 0.38 to 3.65mM and 0.84-7.43mM respectively. The inhibitory effect of As on soil ACP was mostly affected by soil organic matter and cation exchange capacity. Those factors influenced the combination of As with enzyme, which resulted in a difference of As toxicity to soil ACP. Catalytic efficiency (Vmax/Km) of soil ACP was a sensitive kinetic parameter to assess the ecological risks of soil As contamination.

Catalytic efficiency is a better predictor of arsenic toxicity to soil alkaline phosphatase.

Arsenic (As) is an inhibitor of phosphatase, however, in the complex soil system, the substrate concentration effect and the mechanism of As inhibition of soil alkaline phosphatase (ALP) and its kinetics has not been adequately studied. In this work, we investigated soil ALP activity in response to As pollution at different substrate concentrations in various types of soils and explored the inhibition mechanism using the enzyme kinetics. The results showed that As inhibition of soil ALP activity was substrate concentration-dependent. Increasing substrate concentration decreased inhibition rate, suggesting reduced toxicity. This dependency was due to the competitive inhibition mechanism of As to soil ALP. The kinetic parameters, maximum reaction velocity (Vmax) and Michaelis constant (Km) in unpolluted soils were 0.012-0.267mMh-1 and 1.34-3.79mM respectively. The competitive inhibition constant (Kic) was 0.17-0.70mM, which was lower than Km, suggesting higher enzyme affinity for As than for substrate. The ecological doses, ED10 and ED50 (concentration of As that results in 10% and 50% inhibition on enzyme parameter) for inhibition of catalytic efficiency (Vmax/Km) were lower than those for inhibition of enzyme activity at different substrate concentrations. This suggests that the integrated kinetic parameter, catalytic efficiency is substrate concentration independent and more sensitive to As than ALP activity. Thus, catalytic efficiency was proposed as a more reliable indicator than ALP activity for risk assessment of As pollution.

Using Qmsax* to evaluate the reasonable As(V) adsorption on soils with different pH.

As a toxic metalloid element, arsenic (As) derived from human activities can pose hazardous risks to soil and water. The bioavailability of arsenic is influenced by its behavior, in particular its adsorption-desorption in the soil environment. The maximum adsorption amount (Qmax) calculated from Langmuir equation is an important parameter to estimate the adsorption capacity of adsorbents. However, the soil is a more complicated system compared with specific adsorbents. Thus, in this study, we tried to find a more reasonable parameter (Qmax*) to evaluate the adsorption capacity of soils. Eighteen Chinese soil samples with different pH were used for adsorption-desorption experiments. The maximum As(V) adsorption capacity calculated through Langmuir fitting for 18 samples were ranged from 50.25 (S13) to 312.50 (S4) mg kg-1. Besides, Qmax was highly related with soil pH. Using the difference value of adsorption amount and desorption amount to indicate the amount of non-electrostatic adsorption of As(V) onto soils, calculated the maximum adsorption amount of non-electrostatic adsorption (Qmax*). The average Qmax* of acidic and neutral soils was 162.18 mg kg-1 whereas that for alkaline soils it was only 79.52 mg kg-1. The result from multiple linear regression analysis showed Qmax* was strongly influenced by Feox and clay contents. Furthermore, hysteresis index (HI) in the As(V) desorption varied from 0.83 (S13) to 1.82 (S6). The results further indicated the risk of secondary pollution originating from the desorption process cannot be ignored.

Soil mineral alters the effect of Cd on the alkaline phosphatase activity.

The toxicity of heavy metals (HMs) to soil enzymes is directly influenced by the status of the enzyme (free vs. immobilized on minerals) and the duration of exposure. However, little information is available on the interaction effect of HMs, mineral, and exposure time on soil enzyme activities. We investigated the interaction mechanism of alkaline phosphatase (ALP) with minerals (montmorillonite and goethite) and the response of free and immobilized ALP to cadmium (Cd) toxicity under different exposure times. The adsorption isotherms of ALP on both minerals were L-type. The maximum adsorption capacity of goethite for ALP was 3.96 times than montmorillonite, although both had similar adsorption constant (K). Goethite showed a greater inhibitory effect on ALP activity than montmorillonite. The toxicity of Cd to free- and goethite-ALP was enhanced with increasing exposure time, indicating a time-dependent inhibition. However, Cd toxicity to montmorillonite-ALP was not affected by the exposure time. The inhibition of Cd to soil enzyme activity is influenced by the properties of mineral complexes and the duration of exposure. A further understanding of the time pattern of HMs toxicity is helpful for accurately assessing the hazards of HMs to soil enzyme activity.

Application of tegafur gimer, docetaxel and carboplatin in head and neck squamous cell carcinoma therapy.

Squamous cell carcinoma, in the clinical manifestation, is a form of cancer derived from lesions of keratinocytes of epidermis or accessories such as sebaceous ducts, hair follicles, sweat glands, etc. The disease is more common in older men, with prone locations at patients' scalp, face, neck and arms and other exposed parts. Head and neck squamous cell carcinoma (HNSCC) causes a serious impact on patients' daily life, making patients suffer from double blow in mental and physical aspects and reducing patients' life quality. To find effective treatment method for HNSCC, our hospital studies clinical effects of combination therapy of tegafur gimer, docetaxel and carboplatin for the disease. By way of grouping research, therapeutic effect of such treatment and adverse reactions were assessed and analyzed. The study clearly and fully confirms effectiveness of combination therapy of tegafur gimer, docetaxel and carboplatin for HNSCC.

Drying-rewetting alters arsenic ecotoxicity: From the perspective of enzyme-based functional diversity.

Drying-rewetting (DW) cycles can significantly influence soil properties and microbial community composition, leading to direct or indirect changes in arsenic (As) toxicity, which inturn affects soil ecological functions. Despite this, there has been insufficient focus on accurately evaluating As ecotoxicity and its impact on soil ecological function under DW conditions. This study seeks to address this gap by examining the effects of DW on As toxicity and the characteristics of soil ecological function, specifically from the perspective of enzyme-based functional diversity. Our results reveal that compared to constant moisture conditions, DW treatment significantly increased the toxicity of As on alkaline phosphatase and ß-glucosidase, with maximum inhibition rates observed at 46.29% and 21.54%, respectively. Conversely, for other tested enzymes including invertase, fluorescein diacetate hydrolase, and dehydrogenase, DW treatment decreased As toxicity, possibly be due to the different stability of these enzymes under varying soil moisture conditions. From an enzyme functional diversity perspective, DW treatment reduced the As toxicity, as evidenced by the reduced inhibition rates and a lower coefficient of variation. In conclusion, DW appears to enhance soil functional resilience against arsenic pollution. These findings contribute to a better understanding of changes in ecological functions in heavy metal-contaminated soils under dynamic environmental conditions, offering insights for improved monitoring and mitigation strategies for metalloids toxicity in natural environments.

Locally Enhanced Flow and Electric Fields Through a Tip Effect for Efficient Flow-Electrode Capacitive Deionization.

Low-electrode capacitive deionization (FCDI) is an emerging desalination technology with great potential for removal and/or recycling ions from a range of waters. However, it still suffers from inefficient charge transfer and ion transport kinetics due to weak turbulence and low electric intensity in flow electrodes, both restricted by the current collectors. Herein, a new tip-array current collector (designated as T-CC) was developed to replace the conventional planar current collectors, which intensifies both the charge transfer and ion transport significantly. The effects of tip arrays on flow and electric fields were studied by both computational simulations and electrochemical impedance spectroscopy, which revealed the reduction of ion transport barrier, charge transport barrier and internal resistance. With the voltage increased from 1.0 to 1.5 and 2.0 V, the T-CC-based FCDI system (T-FCDI) exhibited average salt removal rates (ASRR) of 0.18, 0.50, and 0.89 µmol cm-2 min-1, respectively, which are 1.82, 2.65, and 2.48 folds higher than that of the conventional serpentine current collectors, and 1.48, 1.67, and 1.49 folds higher than that of the planar current collectors. Meanwhile, with the solid content in flow electrodes increased from 1 to 5 wt%, the ASRR for T-FCDI increased from 0.29 to 0.50 µmol cm-2 min-1, which are 1.70 and 1.67 folds higher than that of the planar current collectors. Additionally, a salt removal efficiency of 99.89% was achieved with T-FCDI and the charge efficiency remained above 95% after 24 h of operation, thus showing its superior long-term stability.

Potential effects of soil petroleum contamination on decomposition of Artemisia annua plant litter.

The accumulation of petroleum contaminants in phytoremediating plants can significantly impact the decomposition of their litter. However, the mechanisms underlying these effects and the potential influence of the contaminant concentration remain unclear. In this study, litter from Artemisia annua plants grown in soil with varying concentrations of petroleum (0, 15, 30, and 45 g kg-1) was collected. The litter samples were then inoculated with soil microorganisms and subjected to an indoor simulation of decomposition under controlled temperature and humidity conditions. Changes in the chemical properties, activities of decomposition-related enzymes in the litter, and decomposition rates were measured. Additionally, structural equation modeling was employed to analyze the mechanism through which soil petroleum contamination affects litter decomposition. The findings revealed several key points: (1) increasing soil petroleum contamination tended to reduce the concentration of carbon and nitrogen in litter while increasing those of lignin and total petroleum hydrocarbons (TPH). (2) Soil petroleum contamination tended to increase the activities of both total lignocellulases and total nutrient cycling-related enzymes in litter. (3) Soil petroleum contamination might indirectly inhibit the activity of lignocellulases by increasing the concentration of lignin and TPH in litter. However, it might also directly accelerate the activity of these enzymes, resulting in contradictory effects on litter decomposition. (4) Finally, A. annua litter produced in soil contaminated with 15 and 30 g kg-1 of petroleum exhibited significantly lower decomposition rates than that from uncontaminated soil.

The Accurate and Exclusive Quantification of Somatic Cells in Raw Milk with an OPD-Cu2+ System-Based Colorimetric Method.

The somatic cell count (SCC) refers to the number of somatic cells present in each milliliter of raw milk and serves as a crucial indicator of dairy cow udder health and raw milk quality. Traditional SCC detection methods are often time-consuming, expensive, and susceptible to bacterial interference, rendering them unsuitable for the rapid and unbiased assessment of raw milk quality. Consequently, there is an urgent need for a low-cost, accurate, and user-friendly SCC quantification method. Here, a method based on an OPD-Cu2+ system for SCC quantification was developed. It was found that OPD oxidation signals exhibited a linear correlation with SCC. Following optimization, the detection system was established with a Cu2+ concentration of 25 µM, an OPD concentration of 2 mM, and an incubation time of 15 min. Furthermore, the method demonstrated significant resistance to bacterial interference, though it produced weaker signals in response to bacteria. The somatic cell recovery rate in milk after pretreatment was 88.9%, and SCC was quantified accurately within 45 min, with a linear range of 104-106 cells/mL. In summary, the method developed is cost-effective, straightforward, and facilitates precise somatic cell quantification, offering significant practical value and a new approach for SCC detection in raw milk.