Rapid Methods for Differentiating Reactivated from Residual Phosphatase in Milk and Cream: Collaborative Study

1979 ◽  
Vol 62 (4) ◽  
pp. 822-827
Author(s):  
Gopala K Murthy ◽  
James T Peeler
Keyword(s):  
Magnesium Chloride ◽  
Collaborative Study ◽  
Control Sample ◽  
Rapid Test ◽  
Magnesium Acetate ◽  
Visual Methods ◽  
Test Results ◽  
Milk Samples ◽  
Colorimetric Test ◽  
Photoelectric Colorimeter

Abstract Three methods for differentiating reactivated from residual phosphatase in milk and cream were collaboratively tested using both magnesium acetate and magnesium chloride for reactivating phosphatase. The methods evaluated were the modified Scharer rapid test, the rapid colorimetric test, and the Rutgers method. Nine collaborators tested 6 unknown milk samples containing reactivated and/or residual phosphatase, and 16 collaborators tested 6 unknown cream samples containing reactivated and/or residual phosphatase. Results indicated that use of magnesium acetate in place of magnesium chloride for reactivating phosphatase improved test results. Visual tests (modified Scharer rapid and Rutgers) predicted correct results when the samples contained high levels of reactivated or residual phosphatase. In borderline cases where the reactivated phosphatase contents of the undiluted control sample and the diluted sample containing Mg were very close, the test results of the visual methods were significantly different from 100% correct results at the α = 0.05 level. Use of a photoelectric colorimeter or its equivalent for measuring the absorbance in conjunction with the modified Scharer rapid test improved results considerably. The modified Scharer rapid test was adopted official first action.

Collaborative Study of Rapid Methods for Alkaline Phosphatase in Milk and Cream

1979 ◽  
Vol 42 (10) ◽  
pp. 800-803 ◽  
Author(s):  
G. K. MURTHY ◽  
J. T. PEELER
Keyword(s):  
Alkaline Phosphatase ◽  
Limit Of Detection ◽  
Collaborative Study ◽  
Colorimetric Method ◽  
Skim Milk ◽  
Rapid Test ◽  
Raw Milk ◽  
Colorimetric Test ◽  
Photoelectric Colorimeter

Determination of alkaline phosphatase activity in milk and cream by the modified Scharer rapid test with use of photoelectric colorimeter for measuring absorbance was collaboratively studied. Milk samples (skim milk. milk and cream) with and without added raw milk were sent to 12 collaborators to be tested by (a) the modified Scharer rapid test using commercial standards and phenol standards for comparing colors, (b) the rapid colorimetric test and (c) the Rutgers method. The latter method was used for comparison only. In the modified Scharer rapid test, based on the category of standards, 73.3% of the samples using the commercial standards and 71.6% of the samples using phenol standards were correctly diagnosed. When the scoring was based on positive or negative, 98.4 and 92.6% of the samples were correctly diagnosed. Results with the phenol standards were significantly lower than those observed with the commercial standards. There were no false-positive results, as all incorrect readings were below limit of detection. Most of the errors occurred when the expected value was 1.0 μg phenol/ml. Results were 100% correct for the Rutgers method, but there are only two choices for this method, and they correspond to positive or negative. Compared to the theoretical values, data obtained by the colorimetric method ranged from 1.5 to 18.1% high, with a coefficient of variation of 4.4 to 13.4%. These variations were assumed satisfactory considering the levels at which phosphatase was tested.

Rapid Colorimetric Test for Alkaline Phosphatase in Dairy Products

1979 ◽  
Vol 42 (10) ◽  
pp. 794-799 ◽  
Author(s):  
G. K. MURTHY ◽  
R. MARTIN ◽  
U. S. RHEA ◽  
J. T. PEELER
Keyword(s):  
Alkaline Phosphatase ◽  
Dairy Products ◽  
Rapid Test ◽  
Raw Milk ◽  
Visual Observation ◽  
Visual Methods ◽  
Visual Examination ◽  
Colorimetric Test ◽  
Photoelectric Colorimeter ◽  
Hydrolysis Of

The Scharer rapid test for measuring alkaline phosphatase activity in milk and milk products was modified to include a photoelectric colorimeter in place of visual observation of color. Dairy products containing various amounts of added enzyme (3–15 μg phenol/ml or g) were prepared for analysis as per standard methods and analyzed by the rapid colorimetric test. A linear relationship was found between the percent of raw milk added and the enzyme activity with a correlation coefficient (r) range of 0.963 to 1.000. Hydrolysis of the substrate (disodium phenyl phosphate) by the surviving enzyme in different dairy products was similar. Recovery of the added enzyme varied, depending on the nature of the product. The method is quantitative, reproducible, and can be used as a rapid confirmatory procedure. Similarly, this method was applied to differentiating residual and reactivated enzyme in milk, cream and buttermilk. Compared to the Scharer rapid and the Rutgers visual methods, this test was more reliable in borderline cases because it eliminated the bias encountered in visual examination. A method was developed to analyze alkaline phosphatase in casein.

Collaborative Study of Alkaline Phosphatase Activity in Filter Paper Disks Impregnated with Skim Milk: Positive Control Sample

1982 ◽  
Vol 45 (2) ◽  
pp. 112-114 ◽  
Author(s):  
G. K. MURTHY ◽  
J. T. PEELER
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Alkaline Phosphatase Activity ◽  
Filter Paper ◽  
Room Temperature ◽  
Collaborative Study ◽  
Control Sample ◽  
Skim Milk ◽  
Positive Control ◽  
Colorimetric Test

The rapid colorimetric test was used in a collaborative study to determine alkaline phosphatase activity in filter paper disks impregnated with skim milk then dried and stored for several months at room temperature. Five samples of filter paper disks (0 to 6 μg phenol/disk) in duplicate were sent to six collaborators for analysis. Computations of analytical and analyst errors showed variations of 22.2 to 48.8%. Most of the variations were due to differences among analysts, but some were partly due to differences in the slopes of the calibration curves (a = 0.05 level) they prepared at the time of analysis. Collaborator's performance was evaluated by comparing % correct results that were positive (negative) with the expected results. About 95% of the samples were correctly analyzed.

scholarly journals Delvotest SP for Detection of Cloxacillin and Sulfamethoxazole in Milk: IDF Interlaboratory Study

1998 ◽  
Vol 81 (5) ◽  
pp. 978-990 ◽  
Author(s):  
Gertraud Suhren ◽  
Robert Beukers
Keyword(s):  
Antimicrobial Agents ◽  
Small Difference ◽  
Collaborative Study ◽  
Detection Limits ◽  
Test Results ◽  
Response Curves ◽  
Human Errors ◽  
Milk Samples ◽  
Laboratory Test Results ◽  
Limited Experience

Abstract Under the auspices of the International Dairy Federation's Group E503, a collaborative study of the Delvotest SP multiplate microbial inhibitor test was performed to gain information about the detection limits of 2 antimicrobial agents (a β-lactam and a sulfa compound), the variation of test results between users and 2 batches of the test, and the reasons for deviating results. Lyophilized milk samples spiked with various concentrations of cloxacillin or sulfamethoxazole were analyzed. Each substance/concentration combination was tested with each of 2 test batches 14 or 15 times per participating laboratory. Test results were to be read by more than one person and reported on separate forms. Results were obtained from 29 laboratories, which included 5 with no experience and 11 with limited experience with this test. Detection limits for cloxacillin (22.5 or 30 μg/kg, depending on batch) and sulfamethoxazole (45 μg/kg) were established from dose-response curves. A small difference in cloxacillin detection levels between the 2 test batches was observed. Analyses of samples gave almost unanimous results (≥95%). Of deviating results, defined as anomalous results (1.4% of readings), half could be attributed to human errors and half to procedural errors

Determination of Alkaline Phosphatase in Casein: Collaborative Study

1981 ◽  
Vol 64 (3) ◽  
pp. 623-627
Author(s):  
Gopala K Murthy ◽  
James T Peeler ◽  
◽  
E E Bone ◽  
B Dickerson ◽  
...  
Keyword(s):  
Alkaline Phosphatase ◽  
Phosphatase Activity ◽  
Collaborative Study ◽  
Magnesium Acetate ◽  
Colorimetric Test

Abstract A collaborative study was made to determine alkaline phosphatase in casein samples by the rapid colorimetric test. Six to eight collaborators tested 10 unknown casein samples containing various amounts of residual phosphatase with and without the addition of magnesium acetate. Results indicated that magnesium acetate significantly increased phosphatase activity. The collaborators correctly analyzed 95% of the samples with the added magnesium acetate. The method has been adopted official first action.

scholarly journals Human Saliva-Mediated Hydrolysis of Eugenyl-β-D-Glucoside and Fluorescein-di-β-D-Glucoside in In Vivo and In Vitro Models

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 172
Author(s):  
Mariusz Dziadas ◽  
Adam Junka ◽  
Henryk Jeleń
Keyword(s):  
Oral Cavity ◽  
Control Sample ◽  
Rapid Test ◽  
Human Saliva ◽  
In Vitro Models ◽  
Microbial Hydrolysis ◽  
Amoxicillin Trihydrate ◽  
Potassium Clavulanate

Eugenyl-β-D-glucopyranoside, also referred to as Citrusin C, is a natural glucoside found among others in cloves, basil and cinnamon plants. Eugenol in a form of free aglycone is used in perfumeries, flavourings, essential oils and in medicinal products. Synthetic Citrusin C was incubated with human saliva in several in vitro models together with substrate-specific enzyme and antibiotics (clindamycin, ciprofloxacin, amoxicillin trihydrate and potassium clavulanate). Citrusin C was detected using liquid chromatography with tandem mass spectrometry (LC-MS/MS). Citrusin C was completely degraded only when incubated with substrate-specific A. niger glucosidase E.C 3.2.1.21 (control sample) and when incubated with human saliva (tested sample). The addition of antibiotics to the above-described experimental setting, stopped Citrusin C degradation, indicating microbiologic origin of hydrolysis observed. Our results demonstrate that Citrusin C is subjected to complete degradation by salivary/oral cavity microorganisms. Extrapolation of our results allows to state that in the human oral cavity, virtually all β-D-glucosides would follow this type of hydrolysis. Additionally, a new method was developed for an in vivo rapid test of glucosidase activity in the human mouth on the tongue using fluorescein-di-β-D-glucoside as substrate. The results presented in this study serve as a proof of concept for the hypothesis that microbial hydrolysis path of β-D-glucosides begins immediately in the human mouth and releases the aglycone directly into the gastrointestinal tract.

scholarly journals Evaluating Presence/Absence of Target Microbes in Microbiological Tests

2000 ◽  
Vol 83 (6) ◽  
pp. 1429-1434
Author(s):  
Robert J Blodgett ◽  
Anthony D Hitchins
Keyword(s):  
Performance Studies ◽  
Collaborative Study ◽  
False Negative ◽  
The Other ◽  
Test Results ◽  
Logistic Curve ◽  
Microbiological Method ◽  
Test Portion ◽  
Method Performance ◽  
Data Set

Abstract A typical qualitative microbiological method performance (collaborative) study gathers a data set of responses about a test for the presence or absence of a target microbe. We developed 2 models that estimate false-positive and false-negative rates. One model assumes a constant probability that the tests will indicate the target microbe is present for any positive concentration in the test portion. The other model assumes that this probability follows a logistic curve. Test results from several method performance studies illustrate these estimates.

Cryoscopy of Milk: Effect of Variations in the Method

1966 ◽  
Vol 49 (3) ◽  
pp. 511-515 ◽  
Author(s):  
R W Henningson
Keyword(s):  
Statistical Analysis ◽  
Sample Size ◽  
Freezing Point ◽  
Collaborative Study ◽  
Sample Temperature ◽  
Milk Samples ◽  
Two Samples ◽  
Temperature Rate

Abstract Bath level, sample temperature, rate of stirring, degree of supercooling, sample size, sample isolation, and refreezing of the sample were the variables in the thermistor cryoscopic method for the determination of the freezing point value of milk chosen for study. Freezing point values were determined for two samples of milk and two secondary salt standards utilizing eight combinations of the seven variables in two test patterns. The freezing point value of the salt standards ranged from –0.413 to –0.433°C and from –0.431 to –0.642°C. The freezing point values of the milk samples ranged from –0.502 to –0.544°C and from –0.518 to –0.550°C. Statistical analysis of the data showed that sample isolation was a poor procedure and that other variables produced changes in the freezing point value ranging from 0.001 to 0.011°C. It is recommended that specific directions be instituted for the thermistor cryoscopic method, 15.040–15.041, and that the method be subjected to a collaborative study.

scholarly journals Influenza colloidal gold method and blood routine tests combination for rapid diagnosis of influenza: a decision tree-based analysis

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Xiaoguang Li ◽  
Jing Chen ◽  
Fei Lin ◽  
Wei Wang ◽  
Jie Xu ◽  
...  
Keyword(s):  
Decision Tree ◽  
Predictive Value ◽  
Colloidal Gold ◽  
Influenza A ◽  
Clinical Manifestations ◽  
Rapid Test ◽  
Test Results ◽  
Tree Model ◽  
Routine Blood ◽  
Test Result

AbstractRapid influenza diagnosis can facilitate targeted treatment and reduce antibiotic misuse. However, diagnosis efficacy remains unclear. This study examined the efficacy of a colloidal gold rapid test for rapid influenza diagnosis. Clinical characteristics of 520 patients with influenza-like illness presenting at a fever outpatient clinic during two influenza seasons (2017–2018; 2018–2019) were evaluated. The clinical manifestations and results of routine blood, colloidal gold, and nucleic acid tests were used to construct a decision tree with three layers, nine nodes, and five terminal nodes. The combined positive predictive value of a positive colloidal gold test result and monocyte level within 10.95–12.55% was 88.2%. The combined negative predictive value of a negative colloidal gold test result and white blood cell count > 9.075 × 109/L was 84.9%. The decision-tree model showed the satisfactory accuracy of an early influenza diagnosis based on colloidal gold and routine blood test results.

scholarly journals Evaluating the bacterial culture technique by Polymerase chain reaction for the diagnosis of Brucella abortus in milk of cows suspected with brucellosis.

2016 ◽  
Vol 40 (1) ◽  
pp. 5-8
Author(s):  
Bashar Sadeq Noomy
Keyword(s):  
Polymerase Chain Reaction ◽  
Brucella Abortus ◽  
Bacterial Culture ◽  
Culture Technique ◽  
Test Results ◽  
Chain Reaction ◽  
Culture Techniques ◽  
Milk Samples ◽  
Polymerase Chain ◽  
Pcr Test

      The aim of this study is to determine the sensitivity of bacterial culture technique in the detection of Brucella abortus in milk samples of aborted cows. Sixty samples of milk were collected from aborted cows during a period which did not exceed two months after the abortion. All of them were positive for rose bengal test. Results showed that Brucella abortus was isolated from 7 out of 60 (11.6%) from the milk of aborted cows, while PCR test showed that 32 out of 60 (53.3%) milk sample contained Brucella abortus. The specificity of culture techniques was 10%, but its sensitivity was only 21.8%. Beside the cautions in dealing with live Brucella abortus (as culture), it is also less sensitive than PCR, though it is better to use PCR technique in the diagnosis of brucellosis in aborted cows milk.

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