Accuracy and Precision of Fossomatic 250/300/360 Series of Somatic Cell Counters Compared to Fossomatic 215: Collaborative Study

1994 ◽  
Vol 77 (4) ◽  
pp. 932-938
Author(s):  
David Mckenna
Keyword(s):  
Somatic Cell ◽  
Second Generation ◽  
Collaborative Study ◽  
Somatic Cells ◽  
Cell Counting ◽  
Third Generation ◽  
Counting Method ◽  
Accuracy And Precision ◽  
Aoac Method ◽  
Cell Counter

Abstract AOAC method 978.26, Somatic Cells in Milk—Optical Somatic Cell Counting Method (Fossomatic), using Fossomatic 215 was adopted first action in 1978 and final action in 1984. The method specifying a second-generation cell counter, the Fossomatic 90, was approved final action in 1989. This demonstrates that the method has been well tested and has satisfied all the requirements of the Association. Since then, the manufacturer, Foss Electric, has introduced a third generation of equipment, which is being distributed as 3 different models. These are the Fossomatic 250, Fossomatic 300, and Fossomatic 360. The models differ only in their packaging and the speed at which they perform analyses.

Collaborative Study of an Automated Optical Somatic Cell Counting Method for Raw Milk

1973 ◽  
Vol 56 (4) ◽  
pp. 950-956
Author(s):  
Wesley N Kelley
Keyword(s):  
Standard Deviation ◽  
Somatic Cell ◽  
Collaborative Study ◽  
Sampling Rate ◽  
Raw Milk ◽  
Cell Counting ◽  
Counting Method ◽  
Milk Samples ◽  
Comparison Of Results ◽  
Statistical Results

Abstract A collaborative study was conducted to compare tbe automated optical somatic cell counting method (OSCC) with the direct microscopic somatic cell counting method (DMSCC) for raw milk. Samples were prefixed with formaldehyde and introduced into an Auto-Analyzer system. Dilution, clarification, and cell counting were performed automatically. Eight collaborators participated in the study, analyzing 48 samples in duplicate, using 2 different sampling rates. The results were compared with DMSCC counts reported by 3 different analysts. Statistical results show that the standard deviation for the DMSCC method was 0.1086 and for the OSCC method, at a sampling rate of 30/hr, 0.0911. From comparison of results it appears that the OSCC method is as accurate as, and more precise than, the DMSCC method. The faster sampling rate of the OSCC method (60/hr) has some effect on precision but little effect on accuracy. The method has been adopted as official first action.

Collaborative Study of the Coulter Counter-Chemical Method for Counting Somatic Cells in Raw Milk1

1977 ◽  
Vol 40 (7) ◽  
pp. 456-458 ◽  
Author(s):  
R. E. GINN ◽  
D. R. THOMPSON ◽  
V. S. PACKARD
Keyword(s):  
Standard Deviation ◽  
Somatic Cell ◽  
Somatic Cell Count ◽  
Chemical Method ◽  
Collaborative Study ◽  
Somatic Cells ◽  
Cell Counting ◽  
Milk Samples ◽  
Counting Procedure ◽  
Electronic Counting

Variation between laboratories for Electronic Somatic Cell Counting by the chemical method (ESCC) was evaluated by a collaborative study. Eight laboratories counted somatic cells in 12 milk samples (six replicated samples) by the ESCC method. The somatic cell count for the same milk samples was also evaluated by the Direct Microscopic Somatic Cell Counting procedure (DMSCC) as a comparison for the level of error. The standard deviation of the variation of logarithms of ESCC counts between laboratories was 0.04368. The standard deviation for the variation of logarithms of DMSCC counts between technicians was 0.08617. The corresponding value for the DMSCC analysis of the last set of federal split milk samples was 0.141. An earlier study of electronic counting by the centrifuge method showed a standard deviation of 0.0711.

Fossomatic Method of Somatic Cell Counting in Milk: Collaborative Study

1978 ◽  
Vol 61 (4) ◽  
pp. 779-784
Author(s):  
Richard D Mochrie ◽  
Robert J Monroe
Keyword(s):  
Somatic Cell ◽  
Collaborative Study ◽  
Cell Counting ◽  
Th Cells ◽  
Linear Coefficient ◽  
Fresh Milk ◽  
Cell Counts ◽  
Local Standard ◽  
Fully Automatic ◽  
Cell Counter

Abstract Fossomatic, a fully automatic, fluoro-optoelectronic somatic cell counter, was evaluated in 6 laboratories. One set of 6 duplicate milk samples, fresh and preserved, was read with instruments as routinely calibrated to each laboratory’s direct microscopic somatic cell counts (DMSCCs), i.e., local standard. A second set was read after standardizing the instrument to a 3-sample common standard (DMSCC) shipped to each collaborator. Cell levels of the unknowns ranged from 371 to 2301 thousand (th)/ml by DMSCC, with an s per sample of 14.8% and s of a level mean of 1.8%. Fossomatic values averaged 1014 compared to 1031 th cells/ml by DMSCC, had homogeneous variance for duplicates within laboratories (s = 4.0%), and had an error per observation of 6.2%. The linear coefficient of 0.9966±0.0039 (for fresh milk and common standard) for the Fossomatic values regressed on DMSCC gave an excellent and unbiased estimate of the cell concentration in a milk sample. A small bias was evident in only 5 of 24 linear regressions (fresh or preserved within each standard) where slopes differed significantly from 1. All 5 were on values derived from a local standard with maximum biases of +18% and —28% (at a 1 million level). Preserved milk had slightly lower (P < 0.01) cell concentrations than fresh milk but only by 3.6% at 1 million. Although condition X level was significant (P < 0.01), the 6 cell levels differed by a magnitude of only 27— 45 th cells/ml. Between-laboratory variation (the component was 4.6%) and laboratory X level interaction were both significant, but their contributions to error were small. The spread in laboratories at any cell level was about 12% and the error of estimate for a sample sent to 2 laboratories was 6.8%. Although interactions were significant with this precise method, they were not of such a magnitude as to invalidate cell count estimates in practice. The Fossomatic method has been adopted as official first action.

Improved Automated Optical Somatic Cell Counting Method for Raw Milk: Collaborative Study

1978 ◽  
Vol 61 (6) ◽  
pp. 1328-1334
Author(s):  
Wesley N Kelley
Keyword(s):  
Standard Deviation ◽  
Somatic Cell ◽  
Collaborative Study ◽  
Sampling Rate ◽  
Raw Milk ◽  
Cell Counting ◽  
Counting Method ◽  
Milk Samples ◽  
Counting Procedure ◽  
Statistical Results

Abstract A collaborative study was conducted to compare the improved automated optical somatic cell counting procedure (OSCC II) with the direct microscopic somatic cell counting method (DMSCC) in raw milk. Samples were prefixed with formaldehyde and introduced into an Auto- Analyzer system. Dilution, clarification, and cell counting were performed automatically. Five collaborators participated in the study; they analyzed 48 samples in duplicate, using 2 different sampling rates. The results were compared with DMSCC counts reported by 3 different analysts. Statistical results show that the standard deviation for the DMSCC method is 0.0825 and for the OSCC II, at a sampling rate of 80/hr, 0.0434. When results are compared, the OSCC II procedure is as accurate as, and is significantly more precise than, the DMSCC method. The faster sampling rate of the OSCC II at 120/hr has some effect on precision but little effect on accuracy. The method has been adopted as official first action.

Comparison of Methods for Determining Sodium in Fertilizers

1981 ◽  
Vol 64 (3) ◽  
pp. 704-708
Author(s):  
Luis F Corominas ◽  
Víctor M Boy ◽  
Pedro Rojas
Keyword(s):  
Phosphate Rock ◽  
Collaborative Study ◽  
Ammonium Oxalate ◽  
Selective Electrode ◽  
Accuracy And Precision ◽  
Flame Emission ◽  
Aoac Method ◽  
Aoac Official ◽  
Aas Method

Abstract The AOAC official first action method, 2.147-2.150, for flame emission spectrophotometry (FES) determination of sodium in fertilizers was compared with the atomic absorption spectrophotometric (AAS) method and the sodium selective electrode (SSE) method. Ammonium oxalate, which was previously compared with water, H2SO4, HC1, and HNO3, was used to extract the sample for all 3 methods. Three synthetic NPK samples, 3 commercial samples (urea, normal superphosphate, and neutrophos), 1 phosphate rock, and 2 Magruder check samples were used for the study. Statistically significant differences were obtained in averages for most of the samples, but few differences were found in standard deviations. The AAS method showed the best accuracy and precision. Accuracy of the AOAC method is acceptable. The SSE method showed the highest deviations from the theoretical values. A collaborative study is recommended to compare the AOAC with the AAS method.

Optical Somatic Cell Counting and Total Protein Analysis in a Dairy Herd Improvement Program1

1977 ◽  
Vol 40 (10) ◽  
pp. 671-675 ◽  
Author(s):  
N. WANG ◽  
G. H. RICHARDSON
Keyword(s):  
Somatic Cell ◽  
Total Protein ◽  
Potassium Dichromate ◽  
Somatic Cells ◽  
Dairy Herd ◽  
Cell Counting ◽  
Ambient Conditions ◽  
Fresh Milk ◽  
Cell Counts ◽  
Cheese Industry

Milk sample preparation for Optical Somatic Cell Counter II operation was simplified by using a diluter to add fixative, mix, and dilute samples. Potassium dichromate preservative tablets produced a mean increase of 7,000 in somatic cell counts in fresh milk. Samples held at 20–23 C beyond 2 days or at 4–7 C beyond 4 days showed a reduction in somatic cell count. The mean somatic cells in 3 Holstein herds tested over a 6-month period was 3.8 × 105/ml. A 22-month survey of 52.6 thousand Utah Dairy Herd Improvement samples which were shipped under ambient conditions and then held at 5 C until tested, indicated 75% below 400,000 and 2.7% above 1.6 million somatic cells/ml. Casein, noncasein protein, total protein, fat and milk weight data were also obtained on the three herds. Multiple correlations were obtained. The best correlations suggested that testing for total protein and somatic cells in a central laboratory would estimate casein and noncasein protein. Such tests are most valuable for the cheese industry.

COLLABORATIVE STUDY OF CONFIRMATORY TESTING PROCEDURES FOR SOMATIC CELLS IN MILK

1971 ◽  
Vol 34 (6) ◽  
pp. 285-288 ◽  
Author(s):  
R. B. Read ◽  
J. G. Bradshaw ◽  
J. T. Peeler
Keyword(s):  
Somatic Cell ◽  
Cell Count ◽  
Experimental Error ◽  
Somatic Cell Count ◽  
Collaborative Study ◽  
Somatic Cells ◽  
Total Variance ◽  
Testing Procedures ◽  
Collaborative Studies ◽  
Coefficients Of Variation

Collaborative studies were done to establish the experimental error (replicate variance) and the among-analyst variance of three modifications of the Direct Microscopic Somatic Cell Count and the Electronic Somatic Cell Count when used in laboratories that test milk routinely. The lowest total variance of logarithms of 0.00639 was obtained with the electronic procedure, followed by 0.00964 for the field counting modification of the Direct Microscopic Somatic Cell Count. The strip-reticle modification of the latter procedure had a total variance of 0.01251, and the Direct Microscopic Somatic Cell Count modification that involves counting all somatic cells on one strip without the use of a reticle had a variance of 0.03041. The coefficients of variation for the experimental error for the Electronic Somatic Cell Count and for the field counting, strip count with reticle, and strip count without reticle modifications of the Direct Microscopic Somatic Cell Count were 8, 17, 14, and 17%, respectively.

Comparison of Traacs 800 Autoanalyzer with Official Methodology for Total and Available Phosphorus in Fertilizer

1989 ◽  
Vol 72 (5) ◽  
pp. 862-867 ◽  
Author(s):  
Peter F Kane ◽  
Anne L Orcutt ◽  
Janet H Huber
Keyword(s):  
Confidence Level ◽  
Continuous Flow ◽  
Second Generation ◽  
T Test ◽  
Available Phosphorus ◽  
Third Generation ◽  
Average Bias ◽  
Significant Difference ◽  
Aoac Method

Abstract A third generation of continuous flow analyzers, the Traacs 800, as configured for total P2O5 in fertilizers, was compared to the traditional gravimetric methodology. A t-test of routine samples gave t = -1.01 with 23 DF, indicating no significant difference at the 95% confidence level. The average bias, gravimetric minus analyzer, was -0.03% P2O5. The instrument configured for available P2Os was also compared to second generation AAII instrumentation. Bias was shown to exist in both instruments, which could be overcome by use of matrix standards. When routine samples were extracted and compared on the 2 instruments using matrix standards, a t-test gave t = —1.54 with 26 DF, indicating no significant difference. The average bias, Traacs minus AAII, was -0.06% P2O5. Official AOAC method status will be pursued for both Traacs methodologies.

Collaborative Study of Accuracy and Precision of Rapid Determination of Fat in Meat and Meat Products by Foss-Let Method

1977 ◽  
Vol 60 (4) ◽  
pp. 853-858 ◽  
Author(s):  
Julio D Pettinati ◽  
Clifton E Swift
Keyword(s):  
Food Industry ◽  
Rapid Determination ◽  
Collaborative Study ◽  
Meat Products ◽  
T Test ◽  
Laboratory Sample ◽  
Accuracy And Precision ◽  
Aoac Method ◽  
Better Than

Abstract Collaborators in 12 meat and food industry laboratories performed 4 fat determinations each on 7 samples of meat and meat products by the rapid (7–10 min) Foss-Let method and compared the results with those obtained by AOAC method 24.005(a) or 24.005(b). From the overall mean of results on all samples, determinations by the Foss-Let method averaged 0.11% fat higher than by the AOAC method. This difference was not significant by the t-test (P = 0.05), which indicated agreement between the compared methods in determining fat content. Precision of the Foss-Let method was equivalent to and generally slightly better than that of the AOAC method. Standard deviations with the Foss-Let method were 0.2 % fat for between-duplicates and for within-laboratory repeatability; 0.4% fat for between-laboratories, including variation due to laboratory-sample interaction; and 0.5% fat for reproducibility between analysts in different laboratories. The Foss-Let method has been adopted as official first action.

Collaborative Study to Determine Effects of Milk Composition on Somatic Cell Counts

1990 ◽  
Vol 53 (1) ◽  
pp. 67-71 ◽  
Author(s):  
J. S. HOGAN ◽  
K. LARRY SMITH ◽  
D. A. TODHUNTER ◽  
P. S. SCHOENBERGER
Keyword(s):  
Somatic Cell ◽  
Protein Content ◽  
Collaborative Study ◽  
Fat Content ◽  
Cell Counting ◽  
Bulk Tank Milk ◽  
Somatic Cell Counts ◽  
Milk Samples ◽  
Cell Counts ◽  
Bulk Tank

Quarter, composite, and bulk tank milk samples were analyzed in a three laboratory collaborative study to determine the relationship of milk fat and protein content with milk somatic cell counts. Milk somatic cell counts were determined by two Coulter counters, a Fossomatic counter, and by direct microscopic somatic cell counting. In general, variability among somatic cell counts measured by different procedures was not related to protein or fat content of milk. The greatest percentage of variation between counts that could be explained by fat content of milk was 20.2% between a Coulter and direct microscopic somatic cell counts. The greatest percentage of variation between counts that could be explained by protein content of samples was 12.9% between a Coulter and Fossomatic counts. Breed of cow from which samples were collected also had little influence on differences among milk somatic cell counts. Differences among milk somatic cell counts due to counting methods did vary among quarter, composite, and bulk tank milk samples.

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