Statistical Aspects of the Microbiological Examination of Foods

Chapter 1: Introduction

• Abstract

Chapter 2: Some basic statistical concepts

• Abstract
• Populations
• Lots and samples
• Average sample populations
• Statistics and parameters
• The central limit theorem

Chapter 3: Frequency distributions

• Abstract
• Types of frequency distribution
• Statistical probability
• The binomial distribution (σ² < μ)
• The Normal distribution
• The Poisson distribution (σ² = μ)
• The negative binomial distribution (σ² > μ)
• Relationships between the frequency distributions
• Transformations

Chapter 4: The distribution of microorganisms in foods in relation to sampling

• Abstract
• Random distribution
• Regular distribution
• Contagious (heterogeneous) distributions
• Effects of sample size

Chapter 5: Statistical aspects of sampling for microbiological analysis

• Abstract
• Attributes and variables sampling
• Binomial and trinomial distributions
• Precision of the sample estimate
• Acceptance sampling by attributes
• Acceptance sampling by variables
• Some statistical considerations about drawing representative samples
• Addendum

Chapter 6: Errors associated with preparing samples for analysis

• Abstract
• Laboratory sampling errors
• Calculation of the relative dilution error
• Effects of gross dilution series errors on the derived colony count

Chapter 7: Errors associated with colony count procedures

• Abstract
• 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

Chapter 8: Errors associated with quantal response methods

• Abstract
• Dilution series and most probable number counts
• Multiple test dilution series
• Special applications of multiple-tube dilution tests
• Other statistical aspects of multistage tests

Chapter 9: Statistical considerations of other methods in quantitative microbiology

• Abstract
• Direct microscopic methods
• Indirect methods

Chapter 10: Measurement uncertainty in microbiological analysis

• Abstract
• Accuracy, trueness and precision
• Measurement uncertainty
• Sampling uncertainty

Chapter 11: Estimation of measurement uncertainty

• Abstract
• The ‘generalised uncertainty method’ or ‘bottom-up’ procedure
• The ‘top-down’ approach to estimation of uncertainty
• Analysis of variance
• Measurement of intermediate reproducibility
• Estimation of uncertainty associated with quantal methods
• Use of reference materials in quantal testing

Chapter 12: Statistical process control using microbiological data

• Abstract
• What is statistical process control?
• Tools for statistical process control
• Shewhart’s control charts for variables data
• CUSUM charts
• The moving windows average
• Control charts for attribute data
• Recent developments in statistical process control

Chapter 13: Validation of microbiological methods for food

• Abstract
• The stages of method development
• What is validation?
• Validation of qualitative methods
• Validation of quantitative methods
• Future directions

Chapter 14: Risk assessment and microbiological criteria for foods

• Abstract
• Risk assessment and food safety objectives
• Microbiological criteria
• The relevance of measurement uncertainty to MC
• Conclusions