Food Proficiency Testing Program Round 36 Whole Milk Powder

Transcription

1 -- REPORT NO. 796 Food Proficiency Testing Program Round 36 Whole Milk Powder December 01 ACKNOWLEDGMENTS PTA wishes to gratefully acknowledge the technical assistance provided for this program by Dr R Hutchinson and Ms R Ryan, Global Proficiency Ltd (New Zealand). Thanks also to Mrs S Giannoulidis, Global Proficiency Pty Ltd (Australia), who arranged for the supply of the samples and Global Proficiency Ltd (New Zealand) for the production of the samples. COPYRIGHT PROFICIENCY TESTING AUSTRALIA 01 PO Box 7507 Silverwater NSW 18 AUSTRALIA

2 -3- CONTENTS 1. FOREWORD 1. FEATURES OF THE PROGRAM 1 3. FORMAT OF THE APPENDICES 4. STATISTICAL DESIGN OF THE PROGRAM 5. OUTLIER RESULTS 3 Table A: Summary Statistics for All Tests 4 Table B: Summary of Statistical Outliers 5 6. PTA AND TECHNICAL ADVISERS' COMMENTS 5 Table C: Method of Measurement Uncertainty Estimation REFERENCES 15 APPENDICES APPENDIX A Summary of Results Moisture A1.1 - A1.3 Total Nitrogen A.1 - A.3 Fat A3.1 - A3.3 Ash A4.1 - A4.3 APPENDIX B Homogeneity and Stability Testing B1.1 APPENDIX C Instructions to Participants C1.1 - C1. Results Sheet C.1

3 -1-1. FOREWORD This report summarises the results of a proficiency testing program involving the analysis of whole milk powder samples. It constitutes the thirty-sixth round of an ongoing series of programs involving chemical analysis of foodstuffs. Proficiency Testing Australia (PTA) conducted the testing program in November 01. The aim of the program was to assess laboratories' ability to competently perform the nominated tests. The Program Coordinator was Dr M Bunt. The Technical Advisers were Dr R Hutchinson and Ms R Ryan, Global Proficiency Ltd (New Zealand). This report was authorised by Mrs F Watton, PTA Quality Business Development Manager.. FEATURES OF THE PROGRAM (a) A total of 1 laboratories participated in the program, all of which returned results for inclusion in the final report. Laboratories from the following states and countries participated: NSW VIC WA 1 QLD MALAYSIA 1 THAILAND 1 INDONESIA 1 PAKISTAN To ensure confidential treatment of results, each laboratory was allocated a unique code number. All reference to participants in this report is by allocated code numbers. (b) The results reported by participants are presented in Appendix A. (c) (d) Laboratories were provided with two samples of approximately 100 g of whole milk powder, labelled PTA 1 and PTA. Participants were requested to determine the levels of: Moisture; Total Nitrogen; Fat; and Ash. Laboratories were required to perform all tests using the routine test methods which would normally be used to test customer supplied samples.

4 -- (e) (f) Laboratories were requested to perform the tests according to the Instructions to Participants provided and to record the results, along with an estimate of their measurement uncertainty (MU) for each result, on the accompanying Results Sheet, which was distributed with the samples. Copies of these documents appear in Appendix C. Prior to sample distribution, seven samples were analysed for homogeneity by Global Proficiency Ltd (New Zealand). An additional three samples were analysed for stability by Global Proficiency Ltd (New Zealand). Based on the results of this testing, the homogeneity and stability of the samples was established (see Appendix B). 3. FORMAT OF THE APPENDICES (a) Appendix A is divided into four sections (A1-A4). These sections contain the analysis of results reported by laboratories for Moisture, Total Nitrogen, Fat and Ash. Each section contains, where appropriate: i) a table of results reported by laboratories, with estimates of their MUs; ii) a table of calculated z-scores and methods used; iii) a listing of the summary statistics; iv) ordered z-score charts; and v) a Youden diagram of laboratories results for the sample pair. (b) (c) Appendix B contains details of the homogeneity and stability testing. Appendix C contains copies of the Instructions to Participants and Results Sheet. 4. STATISTICAL DESIGN OF THE PROGRAM A uniform pair statistical design was chosen for this program. Samples PTA 1 and PTA were identical samples for Moisture, Total Nitrogen, Fat and Ash.

5 -3-5. OUTLIER RESULTS Robust z-scores have been used to assess each laboratory s testing performance. When calculated from single results, z-scores are used to detect excessively large or excessively small results in comparison to the consensus value (the median). Any result with an absolute z-score greater than or equal to 3.0 (i.e or 3.0) is classified as an outlier. Youden two-sample diagrams are presented to highlight laboratory systematic differences. They are based on a plot of each laboratory's pair of results (i.e. sample PTA versus sample PTA 1) and represented by a black spot. These diagrams also feature an approximate 95% confidence ellipse for the bivariate analysis of the results, and dashed lines which mark the median value for each of the samples. All points which lie outside the ellipse are labelled with the laboratory's code number. Note however that these points may not correspond with those identified as outliers. This is because the outlier criteria ( z 3.0) has a confidence level of approximately 99%, whereas the ellipse is an approximate 95% confidence region. The points outside the ellipse on the Youden diagram roughly correspond to those with z-scores greater than.0 or less than -.0. Laboratories which are outside the ellipse but have not been identified as outliers (i.e. have.0 < z < 3.0) are encouraged to review their results. As a guide to the interpretation of these diagrams: (i) (ii) laboratories with significant systematic error components (i.e. betweenlaboratory variation) will usually have results outside the ellipse in either the upper right hand quadrant (as formed by the median lines) or the lower left hand quadrant (i.e. unusually high or low results for both samples); and laboratories with significant random error components (i.e. withinlaboratory variation) will have returned results that are substantially more variable than other participants, and these results will usually lie outside the ellipse in either the upper left or lower right hand quadrants (i.e. an unusually high result for one sample and low for the other). For further details on the calculation and interpretation of robust z-scores and the construction and interpretation of Youden diagrams, please see the Guide to Proficiency Testing Australia (01).

6 -4- Table A: Summary Statistics for All Tests The following table summarises the results submitted by participants for the program. Test Summary Statistics PTA 1 PTA Moisture (% m/m) Total Nitrogen (% m/m) Fat (% m/m) Ash (% m/m) Number of Results 1 1 Median Normalised IQR Uncertainty (Median) Number of Results 1 1 Median Normalised IQR Uncertainty (Median) Number of Results 1 1 Median Normalised IQR Uncertainty (Median) Number of Results 1 1 Median Normalised IQR Uncertainty (Median) Notes: 1. For each test, the results for all test methods were pooled and the summary statistics, above, are for the pooled results.. Summary statistics were calculated for the average result for each sample. 3. The uncertainty of the median was calculated as: π normiqr. n

7 -5- Table B: Summary of Statistical Outliers The following table lists the laboratories (by code number) that obtained outliers for each test. Test Sample PTA 1 Sample PTA Moisture 7, 10 7, 10 Total Nitrogen, 3, 4 Fat 8, Ash, 4, 5-6. PTA AND TECHNICAL ADVISERS COMMENTS Consensus values (medians), derived from participants results, are used as the assigned values in this program. These values are not metrologically traceable to an external reference. The summary statistics, uncertainties of the assigned values and outliers, for each of the tests, are reported in Tables A and B above. Complete details of the statistical analyses appear in Appendix A. 6.1 Return Rate All of the 1 laboratories that participated in the program submitted results for inclusion in the final report. The return rate for all tests is as follows: Moisture 1 out of 1 100% Total Nitrogen 1 out of 1 100% Fat 1 out of 1 100% Ash 1 out of 1 100% 6. Performance Summary One or more statistical outliers were reported by eight of the 1 laboratories (67%) that returned results in this round of the Food program. The previous milk powder round of the Food program was Round 3, conducted in March 010 (see Report No. 660 for more details). For comparison, 14% of the participants in Round 3 of the Food program reported statistical outliers. A total of 96 results were analysed in this round of the program. Of these results, 14 (15%) were outlier results. In Round 3 of the Food program 3% of the total results reported were outlier results (see Report No. 660).

8 Moisture Of the 1 laboratories that tested the samples for Moisture, only one laboratory tested using the Australian Standard method, AS Two laboratories tested using AOAC Two laboratories tested using AOAC Seven laboratories tested using other methods. All methods were pooled to analyse the Moisture results. Laboratories 7 and 10 reported outlier results for both samples. Laboratory 5 obtained z-scores >.0 for both samples. Figures AA-1 and AA-, below, show the distribution of results from the methods used for Moisture testing in this round and are included for interest purposes only. Figure AA-1. Spread of results for Moisture proficiency testing of sample PTA 1.

9 -7- Figure AA-. Spread of results for Moisture proficiency testing of sample PTA. The large spread of the results for other methods (Method 5) was due to the variation in the choice of method temperature (70 ºC C). Low temperatures measure free moisture, while high temperatures measure free and bound moisture. The robust CVs of 1.33% and 10.96% for the two samples are higher than the values of 9.40% and 10.7% obtained in Round 3 of the Food program (see Report No. 660). For this round of the program, laboratories were requested to report their MU by repeatability r and/or reproducibility R. Three laboratories reported MU for Moisture by repeatability. Three laboratories reported MU for Moisture by reproducibility. One laboratory reported MU for Moisture by both repeatability and reproducibility. Five laboratories did not provide an estimate of the MU for their Moisture results by either repeatability or reproducibility. Table AA-1. Comparison of reproducibility MU for Moisture calculated from this round with reproducibility MU provided by participants. Reproducibility PTA 1 PTA MU-R (laboratory quoted) Possible significant variation (laboratory codes) 5, 9 5 MU-R (calculated)

10 -8- Table AA-. Comparison of repeatability MU for Moisture calculated from this round with repeatability MU provided by participants. Repeatability PTA 1 PTA MU-r (laboratory quoted) Possible significant variation (laboratory codes) 6, 10, 11 6 MU-r (calculated) Total Nitrogen Four of the 1 laboratories that tested the samples for Total Nitrogen reported using AOAC Two laboratories tested using AOAC 930.9a, including one laboratory that used a modified version of this method. One laboratory tested using AOAC Five laboratories tested using other methods. All methods were pooled to analyse the Total Nitrogen results. Laboratory reported outlier results for both samples. Laboratories 3 and 4 reported outliers for sample PTA. Laboratories 3 and 4 obtained z-scores >.0 for sample PTA 1. Laboratory 1 obtained an z-score >.0 for sample PTA. Laboratory 6 originally reported Protein results instead of Total Nitrogen results. Figures AA-3 and AA-4, below, show the distribution of results from the methods used for Total Nitrogen testing in this round and are included for interest purposes only. Figure AA-3. Spread of results for Total Nitrogen proficiency testing of sample PTA 1.

11 -9- Figure AA-4. Spread of results for Total Nitrogen proficiency testing of sample PTA. For this round of the program, laboratories were requested to report their MU by repeatability r and/or reproducibility R. Three laboratories reported MU for Total Nitrogen by repeatability. Three laboratories reported MU for Total Nitrogen by reproducibility. One laboratory reported MU for Total Nitrogen by both repeatability and reproducibility. Five laboratories did not provide an estimate of the MU for their Total Nitrogen results by either repeatability or reproducibility. Table AA-3. Comparison of reproducibility MU for Total Nitrogen calculated from this round with reproducibility MU provided by participants. Reproducibility PTA 1 PTA MU-R (laboratory quoted) Possible significant variation (laboratory codes) MU-R (calculated) Table AA-4. Comparison of repeatability MU for Total Nitrogen calculated from this round with repeatability MU provided by participants. Repeatability PTA 1 PTA MU-r (laboratory quoted) Possible significant variation (laboratory codes) (11 at margin) MU-r (calculated)

12 Fat Twelve laboratories tested the samples for Fat. The Australian Standard method, AS , was used by three laboratories. Three laboratories tested using AOAC Two laboratories tested using AOAC One laboratory tested using AOAC Three laboratories tested using other methods. All methods were pooled to analyse the Fat results. Laboratory 11 reported outliers for both samples. Laboratory 8 reported an outlier for sample PTA 1. Laboratory 7 obtained z-scores >.0 for both samples. Figures AA-5 and AA-6, below, show the distribution of results from the methods used for Fat testing in this round and are included for interest purposes only. Figure AA-5. Spread of results for Fat proficiency testing of sample PTA 1.

13 -11- Figure AA-6. Spread of results for Fat proficiency testing of sample PTA. The robust CVs of 5.00% and 5.00% for the two samples are lower than the values of 6.33% and 3.3% obtained in Round 3 of the Food program (see Report No. 660). For this round of the program, laboratories were requested to report their MU by repeatability r and/or reproducibility R. Three laboratories reported MU for Fat by repeatability. Three laboratories reported MU for Fat by reproducibility. One laboratory reported MU for Fat by both repeatability and reproducibility. Five laboratories did not provide an estimate of the MU for their Fat results by either repeatability or reproducibility. Table AA-5. Comparison of reproducibility MU for Fat calculated from this round with reproducibility MU provided by participants. Reproducibility PTA 1 PTA MU-R (laboratory quoted) Possible significant variation (laboratory codes) MU-R (calculated) Table AA-6. Comparison of repeatability MU for Fat calculated from this round with repeatability MU provided by participants. Repeatability PTA 1 PTA MU-r (laboratory quoted) Possible significant variation (laboratory codes) MU-r (calculated)

14 Ash Of the 1 laboratories that tested the samples for Ash, only one laboratory tested using the Australian Standard method, AS Four laboratories tested using AOAC Four laboratories tested using AOAC Three laboratories tested using other methods. All methods were pooled to analyse the Ash results. Laboratories, 4 and 5 reported outliers for sample PTA 1. There were no outliers reported for sample PTA. Laboratory 4 obtained an z-score >.0 for sample PTA. Figures AA-7 and AA-8, below, show the distribution of results from the methods used for Ash testing in this round and are included for interest purposes only. Figure AA-7. Spread of results for Ash proficiency testing of sample PTA 1.

15 -13- Figure AA-8. Spread of results for Ash proficiency testing of sample PTA. The robust CVs of 1.35% and 1.85% for the two samples are higher than the values of 0.87% and 0.95% obtained in Round 3 of the Food program (see Report No. 660). For this round of the program, laboratories were requested to report their MU by repeatability r and/or reproducibility R. Three laboratories reported MU for Ash by repeatability. Three laboratories reported MU for Ash by reproducibility. One laboratory reported MU for Ash by both repeatability and reproducibility. Five laboratories did not provide an estimate of the MU for their Ash results by either repeatability or reproducibility. Table AA-7. Comparison of reproducibility MU for Ash calculated from this round with reproducibility MU provided by participants. Reproducibility PTA 1 PTA MU-R (laboratory quoted) Possible significant variation (laboratory codes) - - MU-R (calculated) Table AA-8. Comparison of repeatability MU for Ash calculated from this round with repeatability MU provided by participants. Repeatability PTA 1 PTA MU-r (laboratory quoted) Possible significant variation (laboratory codes) 11 margin 11 margin MU-r (calculated)

16 6.7 Measurement Uncertainty -14- For this round of the program, laboratories were requested to report their MU by repeatability r and/or reproducibility R for each test result. The proportion of MU estimates returned for each individual test is as follows: Test Repeatability (r) Reproducibility (R) Moisture 4 out of 1 33% 4 out of 1 33% Total Nitrogen 4 out of 1 33% 4 out of 1 33% Fat 4 out of 1 33% 4 out of 1 33% Ash 4 out of 1 33% 4 out of 1 33% Participants were also asked to describe the method used for estimating their MU. Six laboratories provided this information, which can be found in Table C below. Table C: Method of Measurement Uncertainty Estimation Lab Code Method GUM - bottom up. 5 Proficiency trial data and in-house precision data. 6 Best guess. 7 In-house precision data. 10 Top down (total MU is reported). 11 Eurachem Citac / Guide. Tables AA-1 - AA-8, on the previous pages, contain the range of results reported by the participants for their MU by repeatability and reproducibility, as well as MU-R and MU-r values calculated from the data. These tables also list laboratories that may have significant variation versus their quoted MU values.

17 REFERENCES 1. Guide to Proficiency Testing Australia (01). (This document is located on the PTA website at under Programs / Documents).. AS Methods of chemical and physical testing for the dairying industry - General methods and principles - Determination of total solids and moisture. 3. AS Methods of chemical and physical testing for the dairying industry - General methods and principles - Determination of nitrogen - Reference Kjeldahl method. 4. AS Methods of chemical and physical testing for the dairying industry - General methods and principles - Determination of fat - Gravimetric method. 5. AS Methods of chemical and physical testing for the dairying industry - General methods and principles - Determination of ash.

18 APPENDIX A Summary of Results

19 Section A1 Moisture

20 Lab Code A1.1 Whole Milk Powder Moisture (% m/m) Results and Measurement Uncertainty Sample PTA 1 Sample PTA Result 1 Result MU r (±) MU R (±) Result 1 Result MU r (±) MU R (±) g g Lab Code Whole Milk Powder Moisture (% m/m) Z-Scores and Methods Sample PTA 1 Sample PTA Method Average Z-Score Average Z-Score Code Temp ( o C) Time (hrs) ± overnight ± mins Method Codes 1 = AS = AOAC = AOAC = IDF 6A 0 5 = Other 7

21 A1. Summary Statistics Statistic Sample PTA 1 Sample PTA Number of Results 1 1 Median Norm IQR Uncertainty (Median) Robust CV 1.33% 10.96% Minimum Maximum Range Notes: 1. denotes an outlier (i.e. z-score 3.0).. Z-scores were calculated for the average result for each sample. 3. The Youden diagram on the following page is provided for information only. 4. Laboratory used AOAC for their Moisture testing. 5. Laboratory 3 used Pearson's Chemical Analysis of Food, 8th Edition, p. 466, for their Moisture testing. 6. Laboratory 4 used AOAC for their Moisture testing. 7. Laboratory 6 used HMA for their Moisture testing. 8. Laboratory 7 used TGA for their Moisture testing. 9. Laboratory 10 used AOAC for their Moisture testing. 10. Laboratory 11 used an in-house method for their Moisture testing.

22 A1.3 Moisture (% m/m) - Sample PTA Robust Z-Score Laboratory Code Moisture (% m/m) - Sample PTA Robust Z-Score Laboratory Code Moisture (% m/m) Sample PTA Sample PTA 1

23 Section A Total Nitrogen

24 Lab Code A.1 Whole Milk Powder Total Nitrogen (% m/m) Results and Measurement Uncertainty Sample PTA 1 Sample PTA Result 1 Result MU r (±) MU R (±) Result 1 Result MU r (±) MU R (±) Lab Code Whole Milk Powder Total Nitrogen (% m/m) Z-Scores and Methods Sample PTA 1 Sample PTA Method Code Average Z-Score Average Z-Score Method Codes 6 = AS = AS Appendix A 0 8 = AOAC = AOAC = AOAC = AOAC 930.9a 1 = IDF 0B 0 13 = Other 5

25 A. Summary Statistics Statistic Sample PTA 1 Sample PTA Number of Results 1 1 Median Norm IQR Uncertainty (Median) Robust CV 6.03% 3.40% Minimum Maximum Range Notes: 1. denotes an outlier (i.e. z-score 3.0).. Z-scores were calculated for the average result for each sample. 3. The Youden diagram on the following page is provided for information only. 4. Laboratory used AOAC for their Total Nitrogen testing. 5. Laboratory 3 used Pearson's Laboratory Techniques in Food, English Edition, 1973, p. 5, for their Total Nitrogen testing. 6. Laboratory 4 used AOAC for their Total Nitrogen testing. 7. Laboratory 6 used a modified version of AOAC 930.9a for their Total Nitrogen testing. 8. Laboratory 6 originally reported Protein results instead of Total Nitrogen results. 9. Laboratory 9 used Dumas for their Total Nitrogen testing. 10. Laboratory 11 used an in-house method for their Total Nitrogen testing.

26 A.3 Total Nitrogen (% m/m) - Sample PTA Robust Z-Score Laboratory Code Total Nitrogen (% m/m) - Sample PTA Robust Z-Score Laboratory Code Total Nitrogen (% m/m) Sample PTA Sample PTA 1

27 Section A3 Fat

28 Lab Code A3.1 Whole Milk Powder Fat (% m/m) Results and Measurement Uncertainty Sample PTA 1 Sample PTA Result 1 Result MU r (±) MU R (±) Result 1 Result MU r (±) MU R (±) g g Lab Code Whole Milk Powder Fat (% m/m) Z-Scores and Methods Sample PTA 1 Sample PTA Method Code Average Z-Score Average Z-Score Method Codes 14 = AS = AOAC = AOAC = AOAC = IDF 9C 0 19 = Other 3

29 A3. Summary Statistics Statistic Sample PTA 1 Sample PTA Number of Results 1 1 Median Norm IQR Uncertainty (Median) Robust CV 5.00% 5.00% Minimum Maximum Range Notes: 1. denotes an outlier (i.e. z-score 3.0).. Z-scores were calculated for the average result for each sample. 3. The Youden diagram on the following page is provided for information only. 4. Laboratory used AOAC for their Fat testing. 5. Laboratory 3 used Pearson's Chemical Analysis of Food, 8th Edition, p. 467, for their Fat testing. 6. Laboratory 11 used an in-house method for their Fat testing.

30 A3.3 Fat (% m/m) - Sample PTA 1 3 Robust Z-Score Laboratory Code Fat (% m/m) - Sample PTA 3 Robust Z-Score Laboratory Code Fat (% m/m) Sample PTA Sample PTA 1

31 Section A4 Ash

32 Lab Code A4.1 Whole Milk Powder Ash (% m/m) Results and Measurement Uncertainty Sample PTA 1 Sample PTA Result 1 Result MU r (±) MU R (±) Result 1 Result MU r (±) MU R (±) g g Lab Code Whole Milk Powder Ash (% m/m) Z-Scores and Methods Sample PTA 1 Sample PTA Method Average Z-Score Average Z-Score Code Temp ( o C) Time (hrs) Method Codes 0 = AS = AOAC = AOAC = AOAC = Other 3

33 A4. Summary Statistics Statistic Sample PTA 1 Sample PTA Number of Results 1 1 Median Norm IQR Uncertainty (Median) Robust CV 1.35% 1.85% Minimum Maximum Range Notes: 1. denotes an outlier (i.e. z-score 3.0).. Z-scores were calculated for the average result for each sample. 3. The Youden diagram on the following page is provided for information only. 4. Laboratory used AOAC and AOAC for their Ash testing. 5. Laboratory 3 used Pearson's Chemical Analysis of Food, 8th Edition, p. 467, for their Ash testing. 6. Laboratory 11 used an in-house method for their Ash testing.

34 A4.3 Ash (% m/m) - Sample PTA Robust Z-Score Laboratory Code Ash (% m/m) - Sample PTA 3 4 Robust Z-Score Laboratory Code Ash (% m/m) Sample PTA Sample PTA 1

35 APPENDIX B Homogeneity and Stability Testing

36 B1.1 Homogeneity Testing Prior to distribution, seven samples of whole milk powder were tested for homogeneity by Global Proficiency Ltd (New Zealand). Each sample was tested in duplicate for Total Nitrogen. The results of the homogeneity testing appear in the following table. Whole Milk Powder Total Nitrogen (% m/m) Sample No. Result A Result B Analysis of this data indicated that the samples were sufficiently homogeneous and, therefore, any participant results identified as outliers cannot be attributed to sample variability. Stability Testing Three samples were tested for stability by Global Proficiency Ltd (New Zealand). The results, below, indicated that the samples were sufficiently stable for use in this program. Whole Milk Powder Total Nitrogen (% m/m) Sample No. Result A Result B

37 APPENDIX C Instructions to Participants and Results Sheet

38 C1.1 PROFICIENCY TESTING AUSTRALIA Food Proficiency Testing Program Round 36, November 01 INSTRUCTIONS TO PARTICIPANTS To ensure that the results of this program can be analysed correctly, participants are asked to note carefully: 1) Two samples of whole milk powder (each approximately 100 g), labelled PTA 1 and PTA, have been provided for compositional analysis. These samples are provided in foil laminated sachets and should be stored below 30 C prior to testing. These samples may be tested for some, or all of the following tests, according to each laboratory s requirements. ) The following tests are to be performed on each sample in duplicate and the results reported: Moisture Total Nitrogen Fat Ash 3) The tests may commence as soon as samples are received. Analysts should be aware of analyte stability and perform tests in an appropriate order. 4) Report results on the attached Results Sheet to the specified number of decimal places. Results should not be reported as greater than. or less than., as such data cannot be statistically analysed. 5) Please identify the methods used on the Results Sheet, using the Method Codes listed on Page of these instructions. Laboratories should use the routine test methods which would normally be used to test customer supplied samples. 6) Laboratories are also requested to calculate and report an estimate of measurement uncertainty (MU) for each reported measurement result. All estimates of measurement uncertainty must be given as a 95% confidence interval (coverage factor k ). 7) Return Results Sheets, either by mail, facsimile or to: Mark Bunt Proficiency Testing Australia PO Box 7507 Telephone: ( ) Silverwater NSW 18 Fax: AUSTRALIA mbunt@pta.asn.au All results should arrive at the above address by no later than Tuesday 7 November 01. Results reported later than this date may not be analysed in the final report. Food, Round 36 November 01 Page 1 of 3

39 C1. PROFICIENCY TESTING AUSTRALIA Food Proficiency Testing Program Round 36, November 01 METHOD CODES Analysis Method Code Moisture (% m/m) Total Nitrogen (% m/m) Fat (% m/m) Ash (% m/m) AS AOAC AOAC IDF 6A Other (please specify) AS AS Appendix A AOAC 99.3 AOAC AOAC AOAC 930.9a IDF 0B Other (please specify) AS AOAC AOAC AOAC IDF 9C Other (please specify) AS AOAC AOAC AOAC Other (please specify) Food, Round 36 November 01 Page of 3

40 C.1 PROFICIENCY TESTING AUSTRALIA Food Proficiency Testing Program Round 36, November 01 RESULTS SHEET Laboratory Code: Date Samples Received: Temperature on Arrival: Test Result 1 Result Sample 1 Sample MU (±) r MU (±) R Result 1 Result MU (±) r MU (±) R Date Tested Method Code Moisture* (0.01% m/m) Total Nitrogen (0.01% m/m) Fat (0.01% m/m) Ash** (0.01% m/m) * Please specify the temperature/time of moisture determination: o C/ hours. ** Please specify the temperature/time of ashing: o C/ hours. Report results for Fat as % fat in sample, not as fat in dry matter. Report measurement uncertainty (MU) by repeatability r and/or reproducibility R. All estimates of MU must be given as a 95% confidence interval (coverage factor k ). Please state below the method used to determine the MU (e.g. GUM (bottom up), proficiency trial data, in-house precision data, Horwitz equation, best guess, etc.) Print Name: Signature & Date: Food, Round 36 November 01 Page 3 of 3

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