Microbiological Risk Assessment in Food Processing

M. Brown, M Stringer

• Publisher: Woodhead Publishing
• Year: 2002
• Print ISBN:
  9781855735859
• eBook ISBN:
  9781855736689
• Topic: Technology & Engineering
• Subtopic: Food Science
• Index: Technology & Engineering

Microbiological risk assessment (MRA) is one of the most important recent developments in food safety management. Adopted by Codex Alimentarius and many other international bodies, it provides a structured way of identifying and assessing microbiological risks in food. Edited by two leading authorities, and with contributions by international experts in the field, Microbiological risk assessment provides a detailed coverage of the key steps in MRA and how it can be used to improve food safety.The book begins by placing MRA within the broader context of the evolution of international food safety standards.Part one introduces the key steps in MRA methodology. A series of chapters discusses each step, starting with hazard identification and characterisation before going on to consider exposure assessment and risk characterisation. Given its importance, risk communication is also covered. Part two then considers how MRA can be implemented in practice. There are chapters on implementing the results of a microbiological risk assessment and on the qualitative and quantitative tools available in carrying out a MRA. It also discusses the relationship of MRA to the use of microbiological criteria and another key tool in food safety management, Hazard Analysis and Critical Control Point (HACCP) systems.With its authoritative coverage of both principles and key issues in implementation, Microbiological risk assessment in food processing is a standard work on one of the most important aspects of food safety management. - Provides a detailed coverage of the key steps in microbiological risk assessment (MRA) and how it can be used to improve food safety - Places MRA within the broader context of the evolution of international food safety standards - Introduces the key steps in MRA methodology, considers exposure assessment and risk characterisation, and covers risk communication

1

Introduction

M. Brown Unilever Research, Sharnbrook

M. Stringer Campden Chorleywood Food Research Association, Chipping Campden

Attempts to assess the nature of the risks posed by foodborne pathogens to consumers have long been undertaken by the food industry as a means of ensuring safe food. However, the 1990s in particular have seen growing government and industry commitment towards developing an internationally- accepted methodology for assessing the importance of microbiological risks. A number of factors have driven this process. Serious and well-publicised outbreaks of foodborne disease in the US and Europe have highlighted the need to improve the identification of new hazards, the assessment and management of existing microbiological food safety risks, and the need for dialogue with consumers about microbiological safety (Pennington, 1997; Tuttle et al., 1999). At the same time, developments in risk assessment methodology, better microbiological data and greater computing power have made it possible to develop more sophisticated and meaningful risk assessments (Tennant, 1997; Benford, 2001; Morgan, 1993).

Further impetus has been provided by the continued globalisation of the food supply, and renewed attempts to harmonise food safety principles and practice in international trade. In 1993 the Uruguay Round of the General Agreement on Tariffs and Trade (GATT) resolved that barriers to international trade in food, including those designed to protect public health, could only be science-based. In response, member countries of the World Trade Organisation (WTO) concluded the sanitary and phytosanitary (SPS) agreement (Anon, 1995a and b). The SPS agreement proposed the key requirements necessary to demonstrate equivalent levels of safety in foods originating in different nations, produced by different manufacturing systems and complying with differing regulatory requirements. The agreement requires that food safety measures taken by individual countries are:

• applied only to the extent required to protect human health

• based on scientific principles

• not maintained without scientific evidence

• based on an assessment of the risk to health that is appropriate to the circumstance

The WTO turned for guidance on defining suitable criteria to the Codex Committee on Food Hygiene of the Codex Alimentarius Commission (CAC), the body set up by the WTO and the Food and Agriculture Organisation (FAO) of the United Nations to develop benchmark standards and procedures for international food safety management. The CAC subsequently developed principles and guidelines to define the nature of, and provide a methodology for, assessing the risks to human health from pathogens in foods (Anon., 1996; Anon., 1999). These guidelines provide the foundation for a common methodology for microbiological risk assessment and management by WTO countries.

The CAC defines microbiological risk assessment as a scientifically-based process involving four key steps which are designed to produce a risk estimate:

1. hazard identification

2. hazard characterisation

3. exposure assessment

4. risk characterisation

Hazard identification identifies the causal relationship between a pathogenic agent, an illness and a food as one vector of a specified illness. Hazard characterisation, or dose-response characterisation as this stage is also known, attempts to relate the probability and severity of illness to the dose of the pathogen (or toxin) ingested by the consumer. Exposure assessment seeks to estimate the scale of exposure by assessing how much and how often consumers are exposed to a hazardous agent in food as a result of contamination levels and the effects of processing, distribution and consumer use. Finally, risk characterisation synthesises the output of the previous stages to provide an estimate (qualitative or quantitative) of the level of risk for a defined group of consumers from the identified pathogen in a particular food product.

This introduction shows that microbiological risk assessment is still a relatively new and emerging discipline. Relatively few formal microbiological risk assessments have been completed, in part because of the resources required and the relative paucity of information in some areas. In particular, few formal assessments have been undertaken by the food industry to form the basis for risk management decisions. As a result, much remains to be discovered in the light of practical experience (some of these completed assessments are discussed in Chapter 7). A number of immediate challenges have been identified by individual formal assessments. These challenges include (Anon., 2000a and b: Ross and McMeekin, 2002):

• problems in the quantity and quality of suitable and relevant data

• issues in the handling of variability and uncertainty

• the limited availability of trained personnel

• debates over methodology, for example how best to model the inputs of the hazard to the supply chain and the resulting outputs with the product, and how to model dose-response data

• how to express the output of a risk assessment in a way that is both accurate and meaningful to food safety managers and consumers

This book is the first comprehensive review not only of the methodology of microbiological risk assessment in the light of experience, but also of the range of problems encountered in practice and how these might be addressed. Two initial chapters set the scene. The first (Chapter 2) puts microbiological risk assessment in the context of the broader development of international food safety standards, whilst Chapter 3 introduces basic microbiological risk assessment methodology. These chapters are followed by authoritative coverage of the four key stages in microbiological risk assessment (Chapters 4 to 7), explaining and reviewing the individual steps which underpin each stage, the problems involved in a practical study and how they might be overcome or, their effects at least, minimised. A subsequent chapter (Chapter 10) reviews the range of qualitative, quantitative and computational tools (such as predictive modelling) available to support each of these stages in an assessment.

The CAC has placed risk assessment as the first step within a broader framework of risk analysis consisting of:

• risk assessment

• risk communication

• risk management

As its name suggests, risk assessment provides a formal, validated and transparent estimate of the level of risk which can be communicated to key groups, such as policy and decision makers, QA professionals and consumers. Such assessments provide a basis for making decisions, setting priorities and adopting appropriate procedures for food safety management. The book therefore includes a chapter on the challenge of risk communication (Chapter 8). There is also a detailed introduction to the issues involved in using risk assessment as a basis for the effective management of pathogen risks related to food production (Chapter 9). Chapter 11 discusses how such assessments can be used to establish microbiological criteria (for specifications) and food safety objectives (FSOs). The chapter shows how these can be used as inputs into food safety management tools such as hazard analysis and critical control point (HACCP) systems, or as benchmarks for establishing equivalence between food safety management or regulatory regimes. Chapter 12 considers in detail the critical relationship between microbiological risk assessment and food safety management systems such as HACCP systems. The concluding chapter looks at the future of microbiological risk assessment, including developments in methodology, risk communication and management, and the acceptance of risk by consumers.

1.1 References

ANON. Results of the Uruguay round of the multilateral trade negotiations 1993: agreement on application of sanitary and phytosanitary measures. Geneva: World Trade Organisation; 1995a.

ANON. Results of the Uruguay round of the multilateral trade negotiations 1993: agreement on technical barriers to trade. Geneva: World Trade Organisation; 1995b.

ANON. Principles and guidelines for the application of microbiological risk assessment. Rome: Codex Alimentarius Commission; 1996.

ANON. Principles and guidelines for the conduct of microbiological risk assessment. Rome: Alinorm 99/13A Codex Alimentarius Commission; 1999.

ANON. Guidelines on hazard characterisation for pathogens in food and water (preliminary document). Rome...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright page
• Contributors
• Preface
• 1: Introduction
• 2: The evolution of microbiological risk assessment
• Part I: The methodology of microbiological risk assessment
• Part II: Implementing microbiological risk assessments
• Index