Collaborative Study of Precision Characteristics of the AOAC Method for Crude Fat in Meat and Meat Products

1977 ◽  
Vol 60 (3) ◽  
pp. 600-608
Author(s):  
Julio D Pettinati ◽  
Clifton E Swift
Keyword(s):  
Food Industry ◽  
Collaborative Study ◽  
Meat Products ◽  
Alternative Methods ◽  
Laboratory Sample ◽  
Aoac Method

Abstract A collaborative study of determination of fat by AOAC method 24.005(a) or (b) was conducted to gain more knowledge regarding its characteristics of precision. Twelve analysts in meat and food industry laboratories each performed 4 determinations on 7 samples containing 3.4–48% fat. The following characteristics of precision of the method were established: Variation between duplicate determinations was 0.3% fat; within-laboratory repeatability on separate days was 0.3% fat for samples containing up to 27% fat and 0.7% for samples containing 48% fat; variation among laboratories, including variation due to laboratory-sample interaction, was 0.4% fat; and reproducibility, which includes variations of determinations on a sample by different analysts using different sets of equipment in different laboratories, was 0.6% fat. This information is especially useful for comparative evaluations of alternative methods of fat determination.

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.

Gravimetric Determination of Moisture and Ash in Meat and Meat Products: NMKL Interlaboratory Study

1992 ◽  
Vol 75 (6) ◽  
pp. 1016-1022 ◽  
Author(s):  
Kurt Kolar
Keyword(s):  
Collaborative Study ◽  
Meat Products ◽  
Drying Method ◽  
Fresh Meat ◽  
Constant Weight ◽  
Mean Values ◽  
Significant Difference ◽  
Aoac Method ◽  
Repeatability And Reproducibility

Abstract Fourteen laboratories participated in a collaborative study of gravimetric methods for determination of moisture and ash in meat and meat products. The determination of moisture by drying without sand at 102-105C for 16-18 h and to constant weight was compared with the official NMKL method using drying with sand to constant weight. The incineration was performed at 550°C. The method was tested on 16 blind duplicate samples of fresh meat and meat products ranging in moisture content from 44.1 to 74.8 g/100 g, and in ash content from 1.0 to 5.4 g/100 g. Drying without sand for 16-18 h and to constant weight gave no significant difference. Therefore, the labor-intensive drying to constant weight is not necessary to obtain reliable results. In comparison with the official NMKL method based on drying with sand, the mean values, repeatability, and reproducibility of the drying method without sand for 16-18 h agree very well. Therefore, there is no reason to retain the more complicated and labor-intensive sand drying method. The conditions of the proposed method differ only slightly from the conditions used in the official AOAC method, 950.46 B(a). The collaborative results for the determination of both moisture and ash gave estimates for precision according to the HORRAT values

Collaborative Study of an Automated Method for the Determination of Nitrogen in Meat Products

1974 ◽  
Vol 57 (4) ◽  
pp. 838-840
Author(s):  
Walter M Gantenbein ◽  
Jon L Schermerhorn ◽  
Elmer George
Keyword(s):  
Room Temperature ◽  
Collaborative Study ◽  
Meat Products ◽  
Automated System ◽  
Average Standard Deviation ◽  
Colorimetric Measurement ◽  
Automated Method ◽  
Average Coefficient ◽  
Aoac Method

Abstract An automated method for nitrogen in meat products was studied collaboratively. Samples were solubilized in sulfuric acid (1 + 1) , cooled to room temperature, and presented to an automated system. Digestion, dilution, and colorimetric measurement of the nitrogen were performed automatically. Samples were also analyzed by the official final action AOAC method, 24.010. Eight collaborators representing 6 laboratories participated in the study. Each participant analyzed 9 different samples in duplicate. Results of the study were satisfactory with an average range of 0.5% protein, average standard deviation of ±0.21%, and average coefficient of variation of 1.20%. The method was found to be as accurate as 24.010 and applicable to meat and meat products containing 0.8–4.0% nitrogen (5.0–25% protein). It has been adopted as official first action.

Enzymatic-Ultraviolet Method for Measuring Lactose in Milk: Collaborative Study

1984 ◽  
Vol 67 (3) ◽  
pp. 637-640 ◽  
Author(s):  
David O Biltcliffe ◽  
Dick H Kleyn ◽  
J Richard Trout ◽  
◽  
D Azzara ◽  
...  
Keyword(s):  
Food Industry ◽  
Collaborative Study ◽  
Skim Milk ◽  
Gravimetric Method ◽  
T Test ◽  
Enzymatic Method ◽  
Commercial Laboratory ◽  
Aoac Method ◽  
Standard Deviations

Abstract Collaborators in 8 dairy and food industry laboratories performed one lactose determination on each of 8 unknown samples of milk, lowfat milk, or skim milk, as 3 pairs of blind duplicates. Two known samples were provided to gain experience prior to analysis of the unknown samples. All of the above samples were also analyzed for lactose content by the official AOAC gravimetric method (16.507) by a commercial laboratory. From the overall mean of results on all samples, determinations by the enzymatic method averaged 0.49% lower than by the AOAC method. This difference was significant by the t-test (P = 0.05), which indicated a lack of agreement between the compared methods in determining lactose content. Standard deviations were similar for the 3 sets of blind duplicates which ranged between 3.67 and 4.55% lactose content. F-values revealed that variations between means obtained by laboratories differed significantly as compared with variations within laboratory means. The method has been adopted official first action.

Colorimetric Determination of Hydroxyproline as Measure of Collagen Content in Meat and Meat Products: NMKL Collaborative Study

1990 ◽  
Vol 73 (1) ◽  
pp. 54-57 ◽  
Author(s):  
Kurt Kolar
Keyword(s):  
Collaborative Study ◽  
Colorimetric Method ◽  
Meat Products ◽  
Acid Oxidation ◽  
Colorimetric Determination ◽  
Mean Values ◽  
Collaborative Studies ◽  
Freeze Dried ◽  
Analytical Result

Abstract A colorimetric method for the determination of hydroxyproline as a measure of collagen in meat and meat products has been collaboratively studied in 18 laboratories. The method includes hydrolysis with sulfuric acid, oxidation with chloramine- T, and formation of a reddish purple complex with 4- dimethylaminobenzaldehyde. Five frozen and 3 freeze-dried samples were tested, ranging in content from 0.11 to 0.88% and from 0.39 to 4.0% hydroxyproline, respectively. The mean values of 2 identical samples were 0.245 and 0.251 %. The average recovery from a spiked sample was 96.1 %. The hydroxyproline content of a known sample (a mixture of 2 samples in the ratio 5:2) was calculated to 1.42%, which agrees well with the analytical result, 1.40%. In comparison with other collaborative studies, based on the ISO analytical method, the repeatability and reproducibility of this method agree well with the other results. This method was accepted as an official NMKL method by all national Committees, and has been adopted official first action by AOAC as an NMKLAOAC method.

Collaborative Study of the Quantitative Gas-Liquid Chromatographic Determination of Fusel Oil and Other Components in Whisky

1972 ◽  
Vol 55 (3) ◽  
pp. 549-556
Author(s):  
J H Kahn ◽  
E T Blessinger
Keyword(s):  
Ethyl Acetate ◽  
Collaborative Study ◽  
Chromatographic Determination ◽  
Official Method ◽  
Fusel Oil ◽  
Fusel Alcohols ◽  
Aoac Method ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic

Abstract Fifteen chemists participated in a collaborative study for the quantitative pas-liquid chromatographic determination of the individual fusel alcohols and ethyl acetate in whisky. Two levels of congeners represented by 4 coded samples of whisky were analyzed by using t h e proposed method, employing a glycerol-1,2,6-hexanetriol column, and the official AOAC method, 9.063-9.065. Since isobutyl and the atnyl alcohols comprise by far the greatest part of fusel oil, their determination is of major importance to the total fusel oil content . Statistical analyses show that the proposed method is superior to the AOAC method for the determination of these alcohols, whereas the official method is superior for the determination of ethyl acetate and n-propyl alcohol. In general, collaborators employing modern instrumentation preferred the proposed method over the AOAC method. The former method also separates and permits the quantitative measurement of active amyl and isoamyl alcohols. The proposed method has been adopted as official first action as an alternative to 9.063–9.065 for the determination of higher alcohols and ethyl acetate in whisky.

Sulfuric Acid/Hydrogen Peroxide Digestion and Colorimetric Determination of Phosphorus in Meat and Meat Products: Collaborative Study

1991 ◽  
Vol 74 (1) ◽  
pp. 22-26 ◽  
Author(s):  
David K Christians ◽  
Thomas G Aspelund ◽  
Scott V Brayton ◽  
Larry L Roberts
Keyword(s):  
Hydrogen Peroxide ◽  
Sulfuric Acid ◽  
Collaborative Study ◽  
Meat Products ◽  
Colorimetric Determination ◽  
Pork Sausage ◽  
Relative Standard ◽  
Significant Difference ◽  
Standard Deviations

Abstract Seven laboratories participated In a collaborative study of a method for determination of phosphorus in meat and meat products. Samples are digested In sulfuric acid and hydrogen peroxide; digestion Is complete In approximately 10 mln. Phosphorus Is determined by colorimetric analysis of a dilute aliquot of the sample digest. The collaborators analyzed 3 sets of blind duplicate samples from each of 6 classes of meat (U.S. Department of Agriculture classifications): smoked ham, water-added ham, canned ham, pork sausage, cooked sausage, and hamburger. The calibration curve was linear over the range of standard solutions prepared (phosphorus levels from 0.05 to 1.00%); levels in the collaborative study samples ranged from 0.10 to 0.30%. Standard deviations for repeatability (sr) and reproducibility (sR) ranged from 0.004 to 0.012 and 0.007 to 0.014, respectively. Corresponding relative standard deviations (RSDr and RSDR, respectively) ranged from 1.70 to 7.28% and 3.50 to 9.87%. Six laboratories analyzed samples by both the proposed method and AOAC method 24.016 (14th Ed.). One laboratory reported results by the proposed method only. Statistical evaluations Indicated no significant difference between the 2 methods. The method has been adopted official first action by AOAC.

Collaborative Study of the Determination of Phosphorus in Gelatin, Dessert Preparations, and Mixes

1972 ◽  
Vol 55 (3) ◽  
pp. 581-582
Author(s):  
Roger G Burkepile
Keyword(s):  
Collaborative Study ◽  
Official Method ◽  
Standard Samples ◽  
Preliminary Work ◽  
Aoac Method ◽  
Standard Deviations

Abstract A collaborative study of the proposed method for phosphorus in gelatin, dessert preparations, and mixes has been conducted. The present AOAC method for phosphorus in fertilizers, 2.023–2.025(a), was modified for this study. Preliminary work by the Associate Referee involving 4 phosphorus standard samples compared the proposed method with the official final action AOAC method for gelatin, 23.004. Additionally, phosphorus standard spikes in gelatin at the 1 and 10 mg P2O5, levels were determined by the proposed method. The proposed method is faster and more sensitive than the official method and is as accurate. Five collaborators and the Associate Referee analyzed 4 prepared samples containing various levels of phosphorus by the proposed method. The standard deviations varied from 0.005 for a 225 Bloom gelatin containing an average of 0.273% P2O5 to 0.016 for a strawberry-flavored commercial gelatin with added lecithin containing an average of 0.110% P2O5. The proposed method has been adopted as official first action to replace 23.004, which was repealed, official first action.

Determination of Geotrichum Mold in Comminuted Fruits and Vegetables: Collaborative Study

1982 ◽  
Vol 65 (5) ◽  
pp. 1095-1096
Author(s):  
Stanley M Cichowicz ◽  
Ruth Bandler ◽  
◽  
R Bandler ◽  
G Dzidowski ◽  
...  
Keyword(s):  
Crystal Violet ◽  
Fruits And Vegetables ◽  
Collaborative Study ◽  
Green Beans ◽  
Aoac Method ◽  
Tomato Products

Abstract The official AOAC method for determination of Geotrichum mold in canned fruits and vegetables (44.079) requires a series of 3 sieves, Nos. 8, 16, and 230, to separate the packing liquid from the product and the mold from the packing liquid. Although this method has been successful for whole or coarsely chopped products (e.g., green beans, potatoes, carrots, and beets), finely divided products such as fruit purees and tomato products tend to clog the sieves. A method was developed in which the product is centrifuged, diluted by volume, stained with crystal violet, and counted with the sieving steps eliminated. The proposed method was adopted official first action.

scholarly journals Determination of Starch, Including Maltooligosaccharides, in Animal Feeds: Comparison of Methods and a Method Recommended for AOAC Collaborative Study

2009 ◽  
Vol 92 (1) ◽  
pp. 42-49 ◽  
Author(s):  
Mary B Hall
Keyword(s):  
Dry Matter ◽  
Collaborative Study ◽  
Ease Of Use ◽  
Acetate Buffer ◽  
Sample Handling ◽  
Animal Feeds ◽  
Heat Stable ◽  
Replacement Method ◽  
Aoac Method

Abstract Starch is a nutritionally important carbohydrate in feeds that is increasingly measured and used for formulation of animal diets. Discontinued production of the enzyme Rhozyme-S required for AOAC Method 920.40 invalidated this method for starch in animal feeds. The objective of this study was to compare methods for the determination of starch as potential candidates as a replacement method and for an AOAC collaborative study. Many starch methods are available, but they vary in accuracy, replicability, and ease of use. After assays were evaluated that differed in gelatinization method, number of reagents, and sample handling, and after assays with known methodological defects were excluded, 3 enzymaticcolorimetric assays were selected for comparison. The assays all used 2-stage, heat-stable, -amylase and amyloglucosidase hydrolyses, but they differed in the gelatinization solution (heating in water, 3-(N-morpholino) propanesulfonic acid buffer, or acetate buffer). The measured values included both starch and maltooligosaccharides. The acetate buffer-only method was performed in sealable vessels with dilution by weight; it gave greater starch values (26 percentage units of sample dry matter) in the analysis of feed/food substrates than did the other methods. This method is a viable candidate for a collaborative study.

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