The Food and Agriculture Organization of the United Nations and the World Health Organization would like to thank the expert drafting groups (see Annex 3) for the time and effort they devoted to the preparation of thorough and comprehensive technical papers on exposure assessment and hazard identification.
Introduction
Background
As a follow-up to this consultation and in response to a request from the CCFH, FAO and WHO jointly launched a program of activities with the aim of providing expert advice on the risk assessment of microbiological hazards in foods to their Member States and to the CAC (see Annex 2). He emphasized that this expert consultation represents the beginning of international work on microbiological risk assessment of specific pathogen/commodity combinations, as suggested by the 32nd session of CCFH, and is important for FAO and WHO member countries and CAC.
Objectives of the Consultation
Jorgen Schlundt, WHO Food Safety Program Coordinator, described the background to the development of the food safety risk analysis framework and the evolution of international microbiological risk assessments through FAO, WHO and Codex initiatives over the past decade. Maria de Lourdes Costarrica, Senior Official, Food Quality Liaison Group, FAO informed the expert consultation that the purpose of this meeting was to provide expert advice and guidance to FAO and WHO member countries based on an assessment of information available for risk assessment of three pathogen-commodity combinations; Salmonella spp.
Summary of the General Discussions
Hazard characterization and exposure assessment of Salmonella spp. in
- HAZARD CHARACTERIZATION OF SALMONELLA IN BROILERS AND
- EXPOSURE ASSESSMENT OF SALMONELLA ENTERITIDIS IN EGGS
- EXPOSURE ASSESSMENT OF SALMONELLA SPP. IN BROILERS
- ISSUES TO BE BROUGHT TO THE ATTENTION OF FAO AND WHO
The model suffers from the nature of the feeding trial data (ie the subjects used were healthy male volunteers) and may not reflect the population at large. Quantitative data measuring the impact of the food matrix effects on the probability of infection. It has been suggested that a linear regression of attack rate on the log10 number of Salmonella consumed may provide an alternative description of the dose-response relationship.
Although no full exposure assessments have been undertaken for this pathogen-commodity combination, models are available that start later in the exposure pathway (eg, the beginning of processing and retail).
Hazard characterization and exposure assessment of Listeria monocytogenes in
HAZARD IDENTIFICATION AND HAZARD CHARACTERIZATION OF
The dose-response relationships model the probability of various biological endpoints, such as infection, morbidity or mortality, as a function of the dose of L ingested. The question is which functional form of the dose-response relationship best describes the reality of the interaction between L. The potential effects of the food matrix on the dose-response relationship were not considered as a variable within any of the models due to insufficient data.
Each of the dose-response models reviewed has specific characteristics and limitations (Figure 6.1 and Table 6.1). Summary of the selected dose-response models available for Listeria monocytogenes reviewed in the current document. 3 US FDA/USDA model: Surrogate test animal is used to establish the shape of the dose-response curve.
The LD50 associated with this r-value should be considered theoretical and interpreted as an indication that a significant proportion of the population is not susceptible. The LD50 associated with this r-value should be considered theoretical and interpreted as an indication that a significant proportion of the population is not susceptible. Better estimates of the actual proportion of the population at increased risk of invasive listeriosis.
EXPOSURE ASSESSMENT OF L. MONOCYTOGENES IN READY-TO-EAT
Gaps in the data that currently prevent the completion of exposure assessments are identified and recommendations are given on improving exposure assessments and their use for RTE foods. The starting point in the exposure assessment depends on the question on which the risk manager is seeking advice. An assessor must often be able to determine the occurrence and concentration at one point in the food chain from an earlier point in the chain because specific data relevant to the point of consumption are not available.
Growth, survival, and death models for L. monocytogenes are now available, including models that reasonably predict growth rates in pure cultures and challenge tests. However, there is evidence that models may be less accurate for foods naturally contaminated with L. monocytogenes. Influence diagram describing factors influencing human exposure to L. monocytogenes in RTE foods. . recognize the limitations of the current generation of predictive microbiological models so that the risk assessment process is transparent.
The report found that it is feasible to develop exposure estimates useful for those managing food safety risks, but there are significant gaps in the data needed to complete estimates for L. In the longer term, the report identified the need to establish an international data repository for data on exposure assessment, including data from All assumptions used in the development of exposure assessment models should be explicitly stated and, where assumptions exist, the validity of these assumptions should be tested and the confidence in the derived exposure estimates defined or determined.
ISSUES TO BE BROUGHT TO THE ATTENTION OF FAO AND WHO
Creating an exposure assessment can be expensive, especially when new data are required, for example for the growth phenomenon of L. The comprehensiveness and thus the cost of the exposure assessment must reflect the importance of the problem being studied. There is evidence that, for at least some RTE foods from similar processing facilities/production lines, the prevalence of L.
However, the factors causing this variability often remain unknown and need to be identified to assess the potential and impact of reducing the prevalence of L. However, the collection of exposure data from outbreaks is difficult due to the long incubation period of listeriosis and the inaccessibility of the exposed food source at the time of illness. The relationship between exposure to microorganisms and factors related to socioeconomic status, food preparation and storage practices, food consumption patterns, frequency of consumption, and other related aspects specific to RTE foods needs further research.
There is a general lack of quantitative data for use in exposure assessment, for example, data on contamination levels as well as prevalence, growth or inactivation kinetics in RTE foods. Collaboration is needed to explore new approaches to develop dose-response models and to stimulate efforts to test the reliability of existing methods with independent data. Criteria must be developed to form the basis for selecting dose-response models and the means to compare them.
Guidelines on Hazard Characterization
INTRODUCTION/CURRENT STATUS
SUMMARY OF THE DISCUSSIONS
Thus, risk characterization for microbiological hazards in foods should be expanded to cover all components of the pathogen, food, and host triangle. Consideration of decisions on tolerable levels of risk are functions of risk management and, therefore, are not within the scope of the Guidance Document. The presentation of the document should clearly describe the way in which the risk characterization contributes to the risk assessment process.
In Section 5.1.1.3, the orientation of the hazard definition will result from the specific purpose of the risk assessment to which it contributes. The determination of adverse effects on human health (Section 7.1) should include reference to methods other than standard dose-response modeling. Guidelines should particularly emphasize the use of epidemiological methods (such as case-control studies, cohort or cross-sectional studies).
Establishing a dose-response function should be based on consideration of a range of different mathematical models, as appropriate. Information on the extent and severity of the disease included in the dose-response modeling (section 7.1.2) should be appropriate for the purpose and scope of the specific risk assessment (e.g. differences in socio-economic and demographic characteristics of consumer populations in different to land). This concept applies to the treatment of inputs and outputs rather than to the structure of the model itself, which must be accurate and unbiased.
FUTURE WORK
Conclusions of the expert consultation
The consultation recognized the specific need for these risk assessments to be applicable to developing countries and the data requirements needed to achieve this. It was also recognized that a prerequisite for the further development of microbiological risk assessment in developing countries is the provision of appropriate technical advice, assistance and training.
Recommendations
Any requests from risk managers for the development of hazard characterization or exposure assessment should contain a clear description of purpose and scope. Reporting of the prevalence and concentration of specified hazards at different stages of the full exposure pathway should be encouraged in all regions of the world. FAO and WHO are encouraged to assist developing countries in preparing project proposals on microbiological risk assessment activities for presentation to potential donors.
Participants
Eric Ebel, USDA, Food Safety and Inspection Service, Bureau of Public Health and Science, 555 South Howes Street, Ft. Sarah Cahill, Food Quality Liaison Group, Food Quality and Standards Service, Food and Nutrition Division, Food and Agriculture Organization of the United Nations (FAO), Rome, Italy. Allan Hogue, Food Safety Programme, Ministry for the Protection of the Human Environment, World Health Organization, 20 Avenue Appia, CH-1211 Geneva 27, Switzerland.
Hajime Toyofuku, Food Safety Programme, Department of Protection of the Human Environment, World Health Organization, 20 Avenue Appia, CH-1211 Geneva 27, Switzerland. Ezzeddine Boutrif, Officer in Charge, Food Quality and Standards Service, Food and Nutrition Division, Food and Agriculture Organization of the United Nations (FAO), Rome, Italy. Jorgen Schlundt, Coordinator, Food Safety Programme, Department of Protection of the Human Environment, World Health Organization, 20 Avenue Appia, CH-1211 Geneva 27, Switzerland.
Richard Ellis, FAO Secretariat of JECFA, Food Quality and Standards Service, Food and Nutrition Division, Food and Agriculture Organization of the United Nations (FAO), Rome, Italy. Peter BenEmbarek, Fish Utilization and Marketing Service Fishery, Industries Division, Fisheries Department, Food and Agriculture Organization of the United Nations (FAO), Rome, Italy. Hector Lupin, Fish Utilization and Marketing Service Fishery, Industries Division, Fisheries Department, Food and Agriculture Organization of the United Nations (FAO), Rome, Italy.
Joint FAO/WHO Microbiological Risk Assessment Activities
List of working documents
