The effect of the number of sample units tested on the precision of microbial colony counts

Food Microbiology

Volumn 28, Issue 6, 2011, Pages 1211-1219

  Jarvis, Basil ^a   Hedges, Alan J ^b  

^a Ross Biosciences Ltd   (United Kingdom)

^b UNIVERSITY OF BRISTOL   (United Kingdom)

Author keywords

Analytical microbiology; Iterative resampling; Measurement uncertainty; Replication; Sample size; Sample units; Statistical modelling

Indexed keywords

ARTICLE; BACTERIAL COUNT; FOOD CONTAMINATION; FOOD CONTROL; METHODOLOGY; SAMPLE SIZE; STANDARD;

COLONY COUNT, MICROBIAL; FOOD CONTAMINATION; FOOD MICROBIOLOGY; SAMPLE SIZE;

EID: 79957936970     PISSN: 07400020     EISSN: 10959998     Source Type: Journal    
DOI: 10.1016/j.fm.2011.04.008     Document Type: Article

References (30)

1. Anon. Proposed Draft Revised Guidelines on Measurement Uncertainty 2009, Codex Alimentarius Commission, Rome, Italy, CX/MAS 09/30/9.
2. Chernick M.R. Bootstrap Methods: A Guide for Practitioners and Researchers 2008, John Wiley and Sons Inc, NJ, USA.
3. Cho E. The variance of sample variance for a finite population. ASA Sect. Surv. Res. Methods (JSM) 2004, 3345-3350.
4. Cho E., Cho M.J. Variance of sample variance. ASA Sect. Surv. Res. Methods (JSM) 2008, 1291-1293.
5. Corry J.E.L., Jarvis B., Hedges A.J. Minimising the between-sample variance in colony counts on foods. Food Microbiol. 2010, 27:598-603.
6. Corry J.E.L., Jarvis B., Passmore S., Hedges A.J. A critical review of measurement uncertainty in the enumeration of food microorganisms. Food Microbiol. 2007, 24:230-253.
7. Davey H.M., Kell D.B. Flow Cytometry and cell Sorting of heterogeneous microbial populations: the importance of single-cell analyses. Microbiol. Rev. 1996, 60:641-696.
8. Davidson A.C., Hinkley D.V. Bootstrap Methods and Their Application. Cambridge Series in Statistical and Probabilistic Mathematics, No 1 1997, University Press, Cambridge, UK.
9. De Bièvre P. Measurement uncertainty is not synonym of measurement repeatability or measurement reproducibility. Accredit.Qual. Assur. 2008, 13:61-62.
10. Commission Regulation (EC) No 2073/2005 of 15 November 2005 on microbiological criteria for foodstuffs. Off. J. Eur. Union 2005, L338:1-26. EU.
11. Feinberg M., Sohier D., David J.F. Validation of an alternative method for counting Enterobacteriaceae in foods based on accuracy profile. J. Assoc. Off. Analyt. Chem. Int. 2009, 92:527-537.
12. Gonzalez-Barron U., Kerr M., Sheridan J.J., Butler F. Count data distributions and their zero-modified equivalents as a framework for modelling microbial data with a relatively high occurrence of zero counts. Int. J. Food Microbiol. 2010, 136:268-277.
13. Hays W.L. Statistics 1994, Harcourt Brace College Publishers, USA, Fort Worth. fifth ed..
14. Horwitz W. Protocol for the design, conduct and interpretation of method performance studies. Pure Appl. Chem. 1995, 67:331-343.
15. Jarvis B., Corry J.E.L., Hedges A.J. Estimates of measurement uncertainty from proficiency testing schemes, internal laboratory quality monitoring and during routine enforcement examination of foods. J. Appl. Microbiol. 2007, 103:462-467.
16. Jarvis B., Hedges A.J., Corry J.E.L. Assessment of measurement uncertainty for quantitative methods of analysis: Comparative assessment of the precision (uncertainty) of bacterial colony counts. Int. J. Food Microbiol. 2007, 116:44-51.
17. Jarvis B. Statistical Aspects of the Microbiological Examination of Foods 2008, Academic Press, London. second ed.
18. Jones P.C.T., Mollinson J.E., Quenouille M.H. A technique for the quantitative estimation of soil microorganisms. J. Gen. Microbiol. 1948, 2:54-69.
19. Kenney J.F., Keeping J.S. Mathematics and Statistics 1951, Pt 2, Van Nostrand, Princeton, N J, p 164. second ed.
20. Kilsby D.C., Baird-Parker A.C. Sampling programmes for the microbiological analysis of food. Society of Applied Bacteriology Symposium Series 1983, Vol. 11:309-315. T.A. Roberts, F.A. Skinner (Eds.).
21. Kilsby D.C., Pugh M.E. The relevance of the distribution of micro-organisms within batches of food to the control of microbiological hazards from foods. J. Appl. Bacteriol. 1981, 51:345-354.
22. Legan J.D., Vandeven M.H., Dahms S., Cole M.B. Determining the concentration of microorganisms controlled by attributes sampling plans. Food Control 2001, 12(3):137-147.
23. Lin J.T. Approximating the cumulative chi-square distribution and its inverse. J. Roy. Stat. Soc. Ser. D 1988, 37:3-5.
24. Lyn J.A., Ramsay M.H., Wood R. Optimised uncertainty in food analysis: application and comparison between four contrasting analyte-commodity combinations. Analyst 2002, 127:1252-1260.
25. Lyn J.H., Ramsey M.H., Wood R. Multi-analyte optimisation of uncertainty in infant food analysis. Analyst 2003, 128:379-388.
26. Lyn J.A., Ramsey M.H., Coad D.S., Damant A.P., Wood R., Boon K.A. The duplicate method of uncertainty estimation: are eight targets enough?. Analyst 2007, 132:1147-1152.
27. Manley B.F.J. Randomisation, Bootstrap and Monte Carlo Methods in Biology 2007, Chapman Hall/CRC, London. third ed..
28. Ramsay M.H., Lyn J.H., Wood R. Optimised uncertainty at minimum overall cost to achieve fitness-for-purpose in food analysis. Analyst 2001, 126:1777-1783.
29. Reinders R.D., De Jonge R., Evers E.G. A statistical method to determine whether micro-organisms are randomly distributed in a food matrix, applied to coliforms and Escherichia coli O157 in minced beef. Food Microbiol. 2003, 20:297-303.
30. Simon J.L. Resampling: The New Statistics 1997, (last accessed 18/02/11). http://www.resample.com/content/text/index.shtml.