Objective:To examine the individual and synergistic anti-listcrial effect of nisin and leaf essential oil of Metasequoia glyptostroboides(M.glyptostroboides) against one of the leading foodhorne pathogens Listeria mon...Objective:To examine the individual and synergistic anti-listcrial effect of nisin and leaf essential oil of Metasequoia glyptostroboides(M.glyptostroboides) against one of the leading foodhorne pathogens Listeria monocytogenes(L.monocytogenes) ATCC 19116 in milk samples.Methods:The whole(8%),low(1%) and skim(no fat content) milk samples were inoculated with L.monocytogenes ATCC 19116 along with leaf essential oil of M.glyptostroboides or nisin alone as well in eomhinations.Results:In this study,the leaf essential oil at the concentrations of 2% and 5% revealed strong anti-listerial effect against L.monocytogenes ATCC 19116 in all categories of milk samples.Nisin at the concentrations of 250 and 500 IU/mL displayed a strong inhibitory effect against ATCC 19116 as compared to the control group.Additionally,synergistic combinations of leaf essential oil(1%) and nisin(62.5,125.250 and 500 IU/mL) also had a remarkable anti-listerial synergism in all the tested milk samples including whole,low and skim milk after 14 days.Conclusions:As a major finding,the leaf essential oil of M.glyptostroboides might he a useful candidate for using in food industry to control the growth of foodhorne pathogenic bacteria as confirmed by its potent anti-listerial Synergistic effect with nisin against L.monocytogenes ATCC 19116 in different milk samples.展开更多
The aim of this study is a present of a simple solvothermal synthesis approach to preparation of Cu-based magnetic metal organic framework(MMOF)and subsequently its application as sorbent for ultrasound assisted magne...The aim of this study is a present of a simple solvothermal synthesis approach to preparation of Cu-based magnetic metal organic framework(MMOF)and subsequently its application as sorbent for ultrasound assisted magnetic solid phase extraction(UAMSPE)of ampicillin(AMP)from cow milk samples prior to high performance liquid chromatography-Ultraviolet(HPLC-UV)determination.Characteristics of prepared MMOF were fully investigated by different techniques which showed the exclusive properties of proposed sorbent in terms of proper functionality,desirable magnetic property and also high specific surface area.Different influential factors on extraction recovery including sorbent dosage,ultrasonic time,washing solvent volume and eluent solvent volume were assessed using central composite design(CCD)based response surface methodology(RSM)as an operative and powerful optimization tool.This is the first report for determination of AMP using MMOF.The proposed method addressed some drawbacks of other methods and sorbents for determination of AMP.The presented method decreases the extraction time(4 min)and also enhances adsorption capacity(250 mg/g).Moreover,the magnetic property of presented sorbent(15 emu/g)accelerates the extraction process which does not need filtration,centrifuge and precipitation procedures.Under the optimized conditions,the proposed method is applicable for linear range of 1.0-5000.0 μg/L with detection limit of 0.29 μg/L,satisfactory recoveries(≥95.0%)and acceptable repeatability(RSD less than 4.0%).The present study indicates highly promising perspectives of MMOF for highly effective analysis of AMP in complicated matrices.展开更多
Cyromazine（CYR） was determined in milk samples using copper（HI） chelate-Triton X-100 chemiluminescence（CL） system associated with flow-injection（FI） in KOH medium. The relative CL intensity for CYR concentrati...Cyromazine（CYR） was determined in milk samples using copper（HI） chelate-Triton X-100 chemiluminescence（CL） system associated with flow-injection（FI） in KOH medium. The relative CL intensity for CYR concentration was linear over the range of 5×10^-4-10μg/mL（R2=0.9990, n=11） with injection rate of 160 h-1 and the relative standard deviation（RSD, n=4） of 1.2%-2.6%. The limit of detection（LOD） for signal-to-noise ratio of 3 was 1.5×10^4μg/mL. The influences of key chemical and physical parameters, some major fresh water ions at their maximum admissible concentrations and a number of pesticides were examined as potential interferences. The concentrations of CYR in spiked milk samples were successfully determined by the proposed method and the results were in good agreement with that of the previously reported HPLC method, having recovery range of （92% a=4%）-（106% a：2%）. The possible CL reaction mechanism for copper（m） chelate-Triton X-100-CYR was also briefly discussed.展开更多
To ensure the quality and safety of pure milk,detection method of typical preservative-potassium sorbate in milk was researched in this paper.Hyperspectral imaging technology was applied to realize rapid detection.Inf...To ensure the quality and safety of pure milk,detection method of typical preservative-potassium sorbate in milk was researched in this paper.Hyperspectral imaging technology was applied to realize rapid detection.Influence factors for hyperspectral data collection for milk samples were firstly researched,including height of sample,bottom color and sample filled up container or not.Pretreatment methods and variable selection algorithms were applied into original spectral data.Rapid detection models were built based on support vector machine method(SVM).Finally,standard normalized variable(SNV)-competitive adaptive reweighted sampling(CARS)and SVM model was chosen in this paper.The accuracies of calibration set and testing set were 0.97 and 0.97,respectively.Kappa coefficient of the model was 0.93.It could be seen that hyperspectral imaging technology could be used to detect for potassium sorbate in milk.Meanwhile,it also provided methodological supports for the rapid detection of other preservatives in milk.展开更多
文摘Objective:To examine the individual and synergistic anti-listcrial effect of nisin and leaf essential oil of Metasequoia glyptostroboides(M.glyptostroboides) against one of the leading foodhorne pathogens Listeria monocytogenes(L.monocytogenes) ATCC 19116 in milk samples.Methods:The whole(8%),low(1%) and skim(no fat content) milk samples were inoculated with L.monocytogenes ATCC 19116 along with leaf essential oil of M.glyptostroboides or nisin alone as well in eomhinations.Results:In this study,the leaf essential oil at the concentrations of 2% and 5% revealed strong anti-listerial effect against L.monocytogenes ATCC 19116 in all categories of milk samples.Nisin at the concentrations of 250 and 500 IU/mL displayed a strong inhibitory effect against ATCC 19116 as compared to the control group.Additionally,synergistic combinations of leaf essential oil(1%) and nisin(62.5,125.250 and 500 IU/mL) also had a remarkable anti-listerial synergism in all the tested milk samples including whole,low and skim milk after 14 days.Conclusions:As a major finding,the leaf essential oil of M.glyptostroboides might he a useful candidate for using in food industry to control the growth of foodhorne pathogenic bacteria as confirmed by its potent anti-listerial Synergistic effect with nisin against L.monocytogenes ATCC 19116 in different milk samples.
基金This work was financially supported by Graduate School and Research Council of Yasouj University.
文摘The aim of this study is a present of a simple solvothermal synthesis approach to preparation of Cu-based magnetic metal organic framework(MMOF)and subsequently its application as sorbent for ultrasound assisted magnetic solid phase extraction(UAMSPE)of ampicillin(AMP)from cow milk samples prior to high performance liquid chromatography-Ultraviolet(HPLC-UV)determination.Characteristics of prepared MMOF were fully investigated by different techniques which showed the exclusive properties of proposed sorbent in terms of proper functionality,desirable magnetic property and also high specific surface area.Different influential factors on extraction recovery including sorbent dosage,ultrasonic time,washing solvent volume and eluent solvent volume were assessed using central composite design(CCD)based response surface methodology(RSM)as an operative and powerful optimization tool.This is the first report for determination of AMP using MMOF.The proposed method addressed some drawbacks of other methods and sorbents for determination of AMP.The presented method decreases the extraction time(4 min)and also enhances adsorption capacity(250 mg/g).Moreover,the magnetic property of presented sorbent(15 emu/g)accelerates the extraction process which does not need filtration,centrifuge and precipitation procedures.Under the optimized conditions,the proposed method is applicable for linear range of 1.0-5000.0 μg/L with detection limit of 0.29 μg/L,satisfactory recoveries(≥95.0%)and acceptable repeatability(RSD less than 4.0%).The present study indicates highly promising perspectives of MMOF for highly effective analysis of AMP in complicated matrices.
文摘Cyromazine（CYR） was determined in milk samples using copper（HI） chelate-Triton X-100 chemiluminescence（CL） system associated with flow-injection（FI） in KOH medium. The relative CL intensity for CYR concentration was linear over the range of 5×10^-4-10μg/mL（R2=0.9990, n=11） with injection rate of 160 h-1 and the relative standard deviation（RSD, n=4） of 1.2%-2.6%. The limit of detection（LOD） for signal-to-noise ratio of 3 was 1.5×10^4μg/mL. The influences of key chemical and physical parameters, some major fresh water ions at their maximum admissible concentrations and a number of pesticides were examined as potential interferences. The concentrations of CYR in spiked milk samples were successfully determined by the proposed method and the results were in good agreement with that of the previously reported HPLC method, having recovery range of （92% a=4%）-（106% a：2%）. The possible CL reaction mechanism for copper（m） chelate-Triton X-100-CYR was also briefly discussed.
基金Supported by the National Key Research and Development Program of China(2016YFD0700204-02)China Agriculture Research System(CARS-36)Heilongjiang Post-doctoral Subsidy Project of China(LBH-Z17020)。
文摘To ensure the quality and safety of pure milk,detection method of typical preservative-potassium sorbate in milk was researched in this paper.Hyperspectral imaging technology was applied to realize rapid detection.Influence factors for hyperspectral data collection for milk samples were firstly researched,including height of sample,bottom color and sample filled up container or not.Pretreatment methods and variable selection algorithms were applied into original spectral data.Rapid detection models were built based on support vector machine method(SVM).Finally,standard normalized variable(SNV)-competitive adaptive reweighted sampling(CARS)and SVM model was chosen in this paper.The accuracies of calibration set and testing set were 0.97 and 0.97,respectively.Kappa coefficient of the model was 0.93.It could be seen that hyperspectral imaging technology could be used to detect for potassium sorbate in milk.Meanwhile,it also provided methodological supports for the rapid detection of other preservatives in milk.
