Statistical Aspects of the Microbiological Examination of Foods, 2nd Edition

Readership

Microbiologists, food microbiologists, applied microbiologists, food scientists, food technologists, official analysts, environmental health officers.

Statistical Aspects of the Microbiological Examination of Foods, 2nd Edition

1 Introduction

2 Some Basic Statistical Concepts
Populations
Lots and Samples
Average Sample Populations
Statistics and Parameters
Variance and Error
References

3 Frequency Distributions
Introduction
Types of frequency distribution
Statistical probability
The Binomial distribution
The Normal distribution
The Poisson Distribution
The Negative Binomial Distribution
Relationship between the frequency distributions
Transformations
References

4 The distribution of microorganisms in foods in relation to sampling
Random distribution
Regular distribution
Contagious (heterogeneous) distributions
Effects of sample size
References

5 Statistical Aspects Of Sampling For Microbiological Analysis
Attributes and Variables Sampling
Binomial and trinomial distributions
Accuracy of the sample estimate
Acceptance sampling by attributes
Acceptance sampling by variables
Statistical considerations about drawing representative samples
References

6 Errors In The Preparation Of Laboratory Samples For Analysis
Laboratory sampling errors
Diluent volume errors
Pipette volume errors
Other sources of error
Calculation of the relative dilution error
References

7 Errors Associated With Colony Count Procedures
Specific technical errors
Pipetting and distribution errors
Limiting precision and confidence limits of the colony count
General technical errors
Comparability of colony count methods
Overall error of colony count methods
References

8 Errors Associated With Quantal Response Methods
Dilution Series and Most Probable Number counts
Multiple Test Dilution Series
Quantification based on relative prevalence of defectives
Some statistical aspects of multi-stage tests
References

9 Statistical Considerations Of Other Methods In Quantitative Microbiology
Direct microscopic methods
Indirect methods
References

10 Measurement Uncertainty in Microbiological Analysis
Accuracy and Precision
Measurement Uncertainty
How is uncertainty estimated?
Reporting of uncertainty
Sampling uncertainty
The use of uncertainty measures in assessing compliance
References

11 Estimation Of Measurement Uncertainty
The ‘Generalised Uncertainty Method’ (GUM) or bottom-up procedure
The Top-down Approach to Estimation of Uncertainty
Analysis of Variance
Robust Methods of Analysis of Variance (ANOVA)
Measurement of Intermediate Reproducibility
Estimation of Uncertainty Associated with Quantal Methods
References

12 Statistical Process Control using Microbiological Data
What is Statistical Process Control?
Trend analysis
Tools for Statistical Process Control
Shewart’s Control Charts for Variables Data
CUSUM Charts
Control Charts for Attribute Data
Conclusion
References

13 Validation of Microbiological Methods
(Dr Sharon Brunelle, AOAC International, Woodville, WA, USA)

The Stages of Method Development
What is Validation?
Statistical Methodologies in Method Validation
Method Comparison – Qualitative Methods
Statistical Analysis of Paired Sample Design - Single Laboratory and Collaborative Laboratory Validation
Statistical Analysis of Unpaired Sample Design - Single Laboratory and Collaborative Laboratory Validation
Method Comparison – Quantitative Methods- Single Laboratory and Collaborative Laboratory Studies
Examination of Data for Outliers
Future Directions
References

14 Statistical aspects of microbiological criteria for foods in relation to Food Safety Objectives
Food Safety Objectives and Risk Assessment
Microbiological Criteria
The relevance of microbial measurement uncertainty to microbiological criteria
Conclusions