Hostname: page-component-586b7cd67f-g8jcs Total loading time: 0 Render date: 2024-11-24T22:55:30.709Z Has data issue: false hasContentIssue false
  • English
  • Français

Statistical inferences about injury and persistence of environmentally stressed bacteria

Published online by Cambridge University Press:  15 May 2009

Martin A. Hamilton  and
Gary K. Bissonnette
Martin A. Hamilton
Affiliation:
Department of Mathematics
Gary K. Bissonnette
Affiliation:
Department of Microbiology, Montana State University, Bozeman, Montana, U.S.A.
Rights & Permissions [Opens in a new window]

Summary

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

A standard technique for ascertaining the survival characteristics of bacteria after being environmentally stressed is to incubate the bacteria on both selective and non-selective media and count the colonies produced. Based on these colony counts, indexes of injury and persistence of the bacteria are calculated. To compare the stress of two different environments, a persistence ratio is calculated. In this paper, methods of statistical inference concerning these indexes and ratios are presented. These statistical methods use well-known procedures for analysis of binomial data and 2 × 2 table data, and are appropriate when the colony counts follow a Poisson distribution.

Type
Research Article
Information
Journal of Hygiene , Volume 74 , Issue 2 , April 1975 , pp. 149 - 155
Copyright
Copyright © Cambridge University Press 1975

References

REFERENCES

Bissonnette, G. K. (1974). Recovery characteristics of bacteria injured in the natural aquatic environment. Ph.D. Dissertation, unpublished.Google Scholar
Cox, D. R. & Lewis, P. A. W. (1968). The Statistical Analysis of Series of Events, p. 226. Methuen & Co.Google Scholar
Clark, C. W. & Ordal, Z. J. (1969). Thermal injury and recovery of Salmonella typhimurium and its effect on enumeration procedures. Applied Microbiology 18, 332–6.CrossRefGoogle ScholarPubMed
Diem, K. & Lentner, C. (eds) (1970). Scientific Tables. Ardsley, N.Y.: Geigy Pharmaceuticals.Google Scholar
Gart, J. J. (1971). The comparison of proportions: a review of significance tests, confidence intervals and adjustments for stratification. Reviews of the International Statistical Institute 39, 148–69.CrossRefGoogle Scholar
Gart, J. J. (1974 a). The analysis of ratios and cross products of ratios of Poisson variates with applications to incidence rates. Paper presented at the meeting of the American Statistical Association, St Louis, Mo., Aug. 1974.Google Scholar
Gart, J. J. (1974 b). The Poisson distribution: the theory and application of some conditional methods. Presented to the International Conference on Characterizations of Statistical Distributions, Calgary, Alberta, Canada, Aug. 1974.Google Scholar
Gart, J. J. & Thomas, D. G. (1972). Numerical results on approximate confidence limits for the odds ratio. Journal of The Royal Statistical Society, Series B, 34, 441–7.Google Scholar
Lehmann, E. L. (1959). Testing Statistical Hypotheses, p. 141. John Wiley & Sons.Google Scholar
McFeters, G. A. & Stuart, D. G. (1972). Survival of coliform bacteria in natural waters: field and laboratory studies with membrane filter chambers. Applied Microbiology 24, 805–11.CrossRefGoogle ScholarPubMed
Ordal, Z. J. (1970). Current developments in the detection of microorganisms in foods: influence of environmental factors on detection methods. Journal of Milk and Food Technology 33, 1–5.CrossRefGoogle Scholar
Ray, B. & Speck, M. L. (1972). Repair of injury induced by freezing Escherichia coli as influenced by recovery medium. Applied Microbiology 24, 258–63.CrossRefGoogle ScholarPubMed
Ray, B. & Speck, M. L. (1973 a). Discrepancies in the enumeration of Escherichia coli. Applied Microbiology 25, 494–8.CrossRefGoogle ScholarPubMed
Ray, B. & Speck, M. L. (1973 b). Enumeration of Escherichia coli in frozen samples after recovery from injury. Applied Microbiology 25, 499–503.CrossRefGoogle ScholarPubMed
Thomas, D. G. (1970). Exact confidence limits for the odds ratio in a 2 × 2 table. Applied Statistics 20, 105–10.CrossRefGoogle Scholar