Quantitative Risk Assessment
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19 results
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Potential for Meta-Analysis in the Realm of Preharvest Food Safety
- Authors: Jan M. Sargeant, Annette M. O’Connor
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Citation: Sargeant J, O’Connor A. 2016. Potential for meta-analysis in the realm of preharvest food safety. 4(5): doi:10.1128/microbiolspec.PFS-0004-2014
- DOI 10.1128/microbiolspec.PFS-0004-2014
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Abstract:
Meta-analysis, the statistical combination of results from multiple studies, can be used to summarize all of the available research on an intervention, etiology, descriptive, or diagnostic test accuracy question. Meta-analysis should be conducted as a component of a systematic review, to increase transparency in the selection of studies and to incorporate an evaluation of the risk of bias in the individual studies included in the meta-analysis. The process of meta-analysis may include a forest plot to graphically display the study results and the calculation of a weighted average summary effect size. Heterogeneity (differences in the effect size between studies) can be evaluated using formal statistics and the reasons for heterogeneity can be explored using sub-group analysis or meta-regression. Thus, meta-analysis may be a useful methodology for preharvest food safety research to aid in policy or clinical decision-making or to provide input to quantitative risk assessment or other models.
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Food Safety Management Systems
- Authors: Virginia N. Scott, Yuhuan Chen
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Source: Pathogens and Toxins in Foods , pp 478-492
Publication Date :
January 2010
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Abstract:
Food safety management can be viewed from different levels: broadly from the perspective of government food safety management systems or more narrowly from that of industry-wide food safety management systems or that of food safety management within an individual establishment. The role of the food industry is to provide safe foods; industry is responsible for establishing food safety management systems that ensure that foods present a minimal risk to the consumer. Risk analysis allows the development of risk-based metrics, such as food safety objectives (FSOs), performance objectives (POs), and performance criteria (PCs), which are addressed in this chapter. Seven hazard analysis and critical control point (HACCP) principles form the framework of a systematic approach to ensure the determination and control of significant food safety hazards associated with a product and process. Monitoring is the first line of defense in the preventive HACCP system. In addition to those related to GMP or sanitation regulations, prerequisite programs can include other programs, such as ingredient specifications, consumer complaint management, glass control programs, allergen management programs, microbiological monitoring of the plant environment, ingredient-to-product traceability programs, and supplier approval programs. PCs can easily be translated into product or process criteria by industry or by government. In integrating a farm-to-fork food safety system, there will be a variety of metrics at points along the food chain.
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Transmission of Antibiotic Resistance from Food Animals to Humans
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Source: Campylobacter, Third Edition , pp 645-665
Publication Date :
January 2008
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Abstract:
Food of animal origin is considered the most important sources of Campylobacter causing infections in humans. This chapter reviews the current knowledge on antimicrobial susceptibility, occurrence of antimicrobial resistance, and transmission of antimicrobial resistant Campylobacter from food animals. Surveillance of antimicrobial resistance in Campylobacter is important for assessing the association between antimicrobial use and occurrence of antibiotic resistance. A total of 4,953 isolates from humans received by the Minnesota Department of Health were tested for resistance to nalidixic acid. Because fluoroquinolones (FQs) use in humans can lead to resistance in Campylobacter during therapy, it can be difficult to determine whether increased resistance in human strains is mainly caused by veterinary or human drug use. There are no known biological reasons why resistant Campylobacter should not transmit from animals to humans as well as susceptible Campylobacter. Several studies have shown that infections with quinolone-resistant Campylobacter in humans are associated with adverse effects for human health, mainly measured by prolonged diarrhea. Campylobacteriosis is one of the most common causes of diarrhea in humans worldwide. Studies aimed at the human health consequences of infections with antimicrobialresistant strains should help guide interventions aimed at limiting the spread of the most important types of resistant strains. The effects of successful intervention measures can be used to direct similar in interventions in other countries and have the potential to considerably improve food safety worldwide.
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Poultry Colonization with Campylobacter and Its Control at the Primary Production Level
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Source: Campylobacter, Third Edition , pp 667-678
Publication Date :
January 2008
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Abstract:
The handling and consumption of poultry is an important source of human campylobacteriosis. It is widely assumed that the control of Campylobacter in meat-producing poultry, with the aim of reducing the numbers of Campylobacter on poultry meat at the retail level, will reduce the public health burden of human campylobacteriosis. This chapter updates the knowledge of poultry infections and their control at the farm level and extends it to include the interface between the farm and the slaughterhouse. The focus of the chapter remains on the control of Campylobacter in primary production because in this food chain, the gut of living poultry is the only amplification point for Campylobacter. Epidemiological and exposure studies have implicated the handling and consumption of poultry meat as an important source for human campylobacteriosis. Colonization is largely in the ceca and is primarily confined to the intestinal mucous layer over the intestinal crypts of the villi. Reducing human campylobacteriosis is an important public health goal in most industrialized countries. Multispecies farming is a clear risk factor for Campylobacter-positive poultry flocks on the same site. The separation of Campylobacter-positive and -negative flocks and decontamination of the meat from positive flocks is an alternative strategy to reducing the risk of campylobacteriosis in humans. One practical control strategy that can be implemented at the farm-slaughterhouse interface is to separate colonized and noncolonized flocks during processing, and to subsequently treat the meat from Campylobacter-positive flocks.
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Risk Assessment of Viruses in Food: Opportunities and Challenges
- Authors: Arie H. Havelaar, Saskia A. Rutjes
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Source: Food-Borne Viruses , pp 221-236
Publication Date :
January 2008
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Abstract:
Microbiological risk analysis originated in the 1980s, with the publication of a seminal paper on dose-response assessment by Haas (23). Building on this, the first studies concerned the safety of drinking water. Viruses were important target organisms in these first studies. Most early risk assessments focused on enteroviruses and rotaviruses, for which culture methods and dose-response information were available (19, 20, 24, 37). These studies demonstrated that risks of viral contamination can be analyzed by the risk assessment paradigm. Risk assessments in the domain of food safety have focused primarily on bacterial pathogens, for which routine culture methods are generally available; quantitative information on the occurrence of bacteria along the food chain has been produced at an increasing pace. Methods to quantify infectious viruses (and protozoa) in foods are generally more complex or not available at all. This implies that quantitative risk assessment for these organisms is hampered by limited data availability even more than are risk assessments of bacterial pathogens.
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Role of Programs Designed To Improve the Microbiological Safety of Imported Food
- Authors: Ewen Todd, Julie A. Caswell
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Source: Imported Foods , pp 209-254
Publication Date :
January 2008
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Abstract:
Conflicting issues often emerge and must be resolved in order to implement an effective strategy to improve the microbiological safety of imported food, as illustrated in the two boxed examples that follow: (i) BSE and the risk of variant Creutzfeld-Jakob Disease (vCJD) from eating beef, and (ii) Salmonella in eggs and broilers. This chapter describes the range of tools adopted to improve the microbiological safety of imported food. The proliferation of private standards and related certification raises important questions regarding their roles in ensuring the microbiological safety of imported food. International organizations play important leadership roles in efforts to improve the microbiological safety of foods. Among these organizations, the Codex Alimentarius Commission (Codex) is particularly important. The Codex standard-setting process and the standards themselves play an influential role in microbiological food safety for imported foods on several levels. In assessing the potential value of risk-based programs to improving the microbiological safety of imported foods, it is also necessary to consider how economics may challenge their value. Risk management is the identification and selection of appropriate food safety controls based on risk assessment and other factors that may be important to the risk management decision. The Hazard Analysis Critical Control Points (HACCP) approach is a prime example of the application of risk management principles in a systematic manner. Government is responsible for introducing or strengthening existing emergency response systems to respond to food bioterrorism by identifying necessary components of an emergency response program.
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Qualitative Risk Assessment
- Author: Marion Wooldridge
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Source: Microbial Risk Analysis of Foods , pp 1-28
Publication Date :
January 2008
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Abstract:
Codex Alimentarius (Codex) and World Organisation for Animal Health (OIE) state that qualitative and quantitative risk assessments have equal validity. In this context “validity” means that, if all the requirements of each of the methods are equally well met, then these two methods are equally valid. This implies that, for these bodies at least, specific requirements must be met for acceptance as a valid qualitative risk assessment. This chapter describes such requirements, giving guidelines as to how they may be achieved and indicating some of the difficulties encountered and issues that arise. In both the Codex and OIE systems, a risk assessment is the term used to describe the complete process of assessing a risk. In both systems it is broken down into several stages. Looking specifically at Codex, those stages include hazard identification and hazard characterization, exposure assessment, and risk characterization. Qualitative risk assessments have been used extensively in import risk assessments of food products intended for human consumption, especially those of animal origin. Specific issues concerned with qualitative risk assessments discussed in this chapter include the reasons for use of a qualitative risk assessment, the differences between a complete qualitative risk assessment and the specific step of qualitative risk characterization (sometimes less distinct than in a quantitative risk assessment), and the complementary nature of qualitative and quantitative risk assessments.
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Using Risk Assessment Principles in an Emerging Paradigm for Controlling the Microbial Safety of Foods
- Authors: Richard C. Whiting, Robert L. Buchanan
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Source: Microbial Risk Analysis of Foods , pp 29-50
Publication Date :
January 2008
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Abstract:
Instituting controls over pathogenic microorganisms in foods reaches back to the beginnings of civilization with the development of salting, fermenting, drying, and cooking processes. The conceptual ‘’food safety objective’’ equation was proposed to overcome some of the limitations of the Hazard Analysis Critical Control Points (HACCP) plan. A bright line focuses on the risk per serving and means that the high doses are always unacceptable, even though they may be very rare. There are several approaches to setting a quantitative appropriate level of protection (ALOP); one begins with the risk manager’s determination that the rate of illness is unacceptably high for a food or class of foods and can be reduced. The decision about an ALOP, of necessity, often focuses on the susceptible human populations. Consumption of foods cannot be easily restricted from certain groups, and the ALOP will need to reflect the more susceptible populations. Traditional assessments of the microbial hazards in foods were based on data for the characteristics of the pathogen, contamination levels, effects of process steps, ability of the pathogen to grow in the food, and the epidemiological record. A dose-response model then relates consumption to the probability of illness or other measure of public health. Thus, the risk assessment links the process parameter values (product pH, storage temperature) to public health (illnesses per serving).
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Microbial Ecology in Food Safety Risk Assessment
- Author: Tom Ross
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Source: Microbial Risk Analysis of Foods , pp 51-97
Publication Date :
January 2008
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Abstract:
The health risks associated with food-and water-borne microbiological hazards are influenced by a complex interplay of variable factors. In this chapter, risk is assumed to relate directly to risk to human health, considering the probability and severity of illness both to individuals and the overall population exposed. The effect of microorganisms is related more to their number than their size, and microbiologists typically think in terms of populations of microbes. It might be expected that development of reliable microbial food safety risk assessments will require a sound understanding of the microbial ecology of foods and the ability to express that understanding mathematically. Microbial hazards in foods can be extremely sensitive to their surroundings and, under some conditions, the microbial ecology of foods has characteristics of a chaotic system. The microbial ecology of foods is deterministic and much is known that can be applied to microbial food safety risk assessment to increase the scientific credibility and utility of risk assessment outcomes. The chapter summarizes knowledge of the deterministic aspects of microbial ecology of foods that is relevant to the conduct of microbial food safety risk assessment; highlights sources of variability and uncertainty in microbial behavior; reviews approaches that have been adopted to model microbial growth, stasis, and death along the farm-to-fork pathway, and identifies sources of information that can assist microbial food safety risk assessors to produce models that are more scientifically rigorous and thus defensible. It discusses five main groups of microorganisms which include algae, fungi, protozoans, bacteria, and viruses.
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The Modular Process Risk Model (MPRM): a Structured Approach to Food Chain Exposure Assessment
- Author: Maarten J. Nauta
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Source: Microbial Risk Analysis of Foods , pp 99-136
Publication Date :
January 2008
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Abstract:
The use of models to quantitatively describe the transmission of pathogens over the food-production chain is increasing in quantitative microbial risk assessment (QMRA). Such models may cover the whole “farm-to-fork” food pathway or only the part that is relevant to the problem. This chapter explains the use of a methodology developed for this purpose: the modular process risk model (MPRM). First, the MPRM methodology is outlined, offering guidelines to perform a food chain QMRA; then, some examples are given to illustrate these guidelines and to show how MPRM has been applied in practical situations. The major advantage of modeling is that it is an instrument that allows an easy comparison of a broad range of alternative scenarios, the main objective of risk assessment. Risk assessment deals with risk, which is a function of probability and severity of an event. As variability and uncertainty can both be represented by probability distributions and the difference between the two is not always obvious, they are easily mixed up. In MPRM food chain risk assessment, the selection of the “best” model depends on the statement of purpose, process knowledge, and data availability.
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Using Risk Analysis for Microbial Food Safety Regulatory Decision Making
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Source: Microbial Risk Analysis of Foods , pp 137-175
Publication Date :
January 2008
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Abstract:
A risk analysis approach emphasizes a shared responsibility for communication about food safety issues by all interested parties including government regulatory officials, industry, consumers, and academics. The three components of risk analysis are risk management, risk assessment, and risk communication. This chapter discusses the use of a risk analysis framework within a food safety context with emphasis on microbiological (biological) hazards, how risk analysis has been implemented in U.S. regulatory agencies and international organizations, and future needs to strengthen the use of risk analysis to help solve food safety issues. Risk analysis requires the interaction of individuals with diverse skills and perspectives, including expertise in communication, coordination, project management, scientific knowledge, and skills in data analysis and modeling. To efficiently allocate resources to address food safety issues, it is vital to establish annual food safety risk management priorities. Risk analysis is emerging as a public health tool that promises to provide a sound scientific basis for developing national and international standards and guidelines for food safety and for supporting risk-based policies and practices to prevent food-borne illness.
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Integrating Concepts: a Case Study Using Enterobacter sakazakii in Infant Formula
- Authors: Martine W. Reij, Marcel H. Zwietering
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Source: Microbial Risk Analysis of Foods , pp 177-204
Publication Date :
January 2008
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Abstract:
This chapter reviews the risk assessment activities that have been performed on Enterobacter sakazakii and focuses on the relations between the various concepts. Other food products besides powdered infant formula (PIF), such as breast milk, starch, and commercially sterilized liquid infant formula, have been described as potentially causing E. sakazakii infections. One of the potential control measures to reduce the risk of E. sakazakii is setting microbiological criteria (MC) for PIF. When a microbial criterion is in place, batches of product need to be sampled at the end of manufacturing, e.g., at packaging, prior to storage. The risk assessment model (RAModel) predicts the number of illnesses due to E. sakazakii per million infant-days, resulting from feeding reconstituted PIF, and compares this number with the numbers resulting from a baseline scenario. Risk communication from users to risk managers is also required. To be able to weigh the various options for control measures, it is imperative that the actual preparation and handling practices become known. Risk assessors can then use the RAModel to compare the options, based on better assumptions regarding temperature, holding times, and cooling rates. Consequently risk managers may be able to design and implement control measures that will effectively reduce the risk, but at the same time take into account all the relevant factors to make sure that the control measures will be feasible and acceptable and can be applied for those infants who are currently most at risk.
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Index
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Source: Microbial Risk Analysis of Foods
Publication Date :
January 2008
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No descriptions available.
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Indicator Microorganisms and Microbiological Criteria
- Authors: Merle D. Pierson, Don L. Zink, L. Michele Smoot
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Source: Food Microbiology: Fundamentals and Frontiers, Third Edition , pp 69-85
Publication Date :
January 2007
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Abstract:
Microbiological criteria provide the food industry and regulatory agencies with guidelines for control of food processing systems and are an underlying component of any critical control point that addresses a microbiological hazard in Hazard Analysis and Critical Control Points (HACCP) systems. Aerobic plate count (APC) or standard plate count (SPC) is commonly used to determine “total” numbers of microorganisms in a food product. Depending on the pathogen, low levels of the microorganism in the food product may or may not be of concern. Some microorganisms have such a low infective dose that their mere presence in a food presents a significant public health risk. For such microbes, the concern is not whether the pathogen is able to grow in the food but that the microorganism could survive for any length of time in the food. Food products frequently subject to contamination by harmful microorganisms, such as shellfish, may benefit from the application of microbiological criteria. Enterococci counts have few useful applications in microbiological criteria for food safety. Some microbiological criteria related to safety rely on tests for metabolites to indicate a potential hazard rather than direct tests for pathogenic or indicator microorganisms. The current acceptable limits are based on the criterion that there is an 80% probability that the plant is actually exceeding the target value if it exceeds the acceptable limit.
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Preface to the Third Edition
- Publication Date : January 2007
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No descriptions available.
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Quantitative Microbial Risk Assessment Model for Legionella: Summary of Methods and Results
- Authors: Thomas W. Armstrong, Charles N. Haas
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Source: Legionella , pp 486-488
Publication Date :
January 2006
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Abstract:
Quantitative microbial risk assessment (QMRA) for Legionella can provide a means of setting risk based limits on air concentration or risk based limits on the Legionella concentrations in water. Guinea pigs provide a reasonable animal model and dose-response data on which to base human risk projections due to similarities in the course of the disease in guinea pigs and humans and in vitro uptake and replication rates of Legionella in human and guinea pig alveolar macrophages. Most mouse and rat strains appear to be relatively resistant to Legionella infection due to less compliant alveolar macrophages. A two-zone box model was used to estimate the air concentrations in CFU/m3, with stochastic input distributions using Monte Carlo simulation to yield results as probability distributions. The respective exposure distributions were fed into the dose-response model using Monte Carlo simulation. The resulting estimated risk distributions were then compared to the reported rates for the outbreaks. The guinea pig infection data adequately predict the reported subclinical (seroprevalence) rates. For the outbreaks used for model evaluation, the reported rates of disease span an order of magnitude. Thus, the QMRA may not extrapolate to other Legionella species and strains.
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Monitoring of Antimicrobial Resistance in Animals: Principles and Practices
- Authors: Scott A. McEwen, Frank M. Aarestrup, David Jordan
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Source: Antimicrobial Resistance in Bacteria of Animal Origin , pp 397-414
Publication Date :
January 2006
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This chapter reviews information relevant to the design and scope of antimicrobial resistance monitoring and surveillance programs for animals and food, with emphasis on program purposes and methods. The chapter describes some of the essential features of existing monitoring and surveillance programs in various countries around the world. It shows how these programs have been useful in improving understanding of resistance and its relation to antimicrobial use and other factors, guiding public policy, and measuring the impact of interventions on antimicrobial resistance in bacteria from animals, food, and humans. The major methodological considerations for the monitoring program include the types of samples to be collected, sampling strategies, species of bacteria, antimicrobials for susceptibility testing, data collection and analysis, and reporting of results. Comprehensive monitoring of antimicrobial resistance in animals in the context of animal and human health covers the entire farm-to-fork continuum. The Food and Drug Administration (FDA) Center for Veterinary Medicine (CVM) has been active in developing new approaches for the preapproval assessment of antimicrobial resistance risks from antimicrobials used in animals. The Japanese Veterinary Antimicrobial Resistance Monitoring (JVARM) program examines the susceptibility of bacteria from food-producing animals to antimicrobial agents. Most programs focus on pathogenic bacteria or Salmonella, but some also report data on resistance in indicator bacteria isolated from healthy animals. Knowledge about antimicrobial resistance should be combined with knowledge regarding the usage of antimicrobial agents for different food animal species, which also should be performed on an internationally comparable basis.
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Risk Assessment and Its Use in Approval, Licensing, and Prudent Use Guidelines
- Author: David Vose
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Source: Antimicrobial Resistance in Bacteria of Animal Origin , pp 415-424
Publication Date :
January 2006
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Abstract:
The purpose of risk assessment is to help a manager better understand the risks (and opportunities) being faced and to evaluate the options available for their control. The chapter describes some antimicrobial resistance risk assessments that have been completed. The Food and Drug Administration (FDA) wanted to produce a model that was based on reliable data. The FDA deemed that the risk assessment had quantitatively demonstrated that the resistance in question presented a risk to human health, and subsequently moved to withdraw use of the antimicrobial. The major strengths of the model were its mathematical simplicity, its reliance on mostly federally collected data, its very limited set of assumptions, and the ease with which it could be updated as new data became available. The data problems underlined the difficulties of evaluating even relatively simple model parameters for antimicrobial risk assessments. The FDA’s quantitative risk analysis model was successful in that it provided robust information from which the FDA was able to make an important decision. A key to the successful involvement of risk assessment in decision making is the neutrality of the risk assessor. There is, unfortunately, a growing trend in published antimicrobial resistance risk assessments that are clearly selective about their sources or manipulate a risk assessment model to produce the desired answer. The FDA guidance takes an essentially qualitative approach to evaluating drugs for approval and continued use.
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Suspicions to Solutions: Characterizing Contaminated Land
- Authors: Lewis R. Barlow, Jim C. Philp
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Source: Bioremediation , pp 49-85
Publication Date :
January 2005
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Abstract:
A successful approach to bioremediation involves site characterization that takes into account careful consideration of appropriate microorganisms, their survivability, and their response to various contaminants. Reliable information on the presence, type, and extent of contamination at a site is therefore vitally important. Risk assessment with respect to contaminated land serves two main purposes. First, it can be used to measure the degree of significance of contamination at a site. Second, the level of cleanup required in order to make a site suitable for its intended use may also be determined. There are four key steps in the process of assessing the risks associated with pollutant linkages: hazard (source) identification, exposure assessment, toxicity assessment, and risk characterization. The long-term leaching potential for soil contaminants and gas generation from organic materials are two common causes for remedial work in advance of development even where existing water quality and soil gas concentrations do not necessarily pose a risk until development has taken place. There are partial models to quantify the risks posed to groundwater, surface water, ecosystems, and human health. The outcome of the investigative and risk assessment processes should be a report that is readily understandable by the client, the other members of the professional team, and the appropriate regulatory authorities. A high standard of presentation is therefore important, and the report should describe the various stages of the work undertaken, together with the findings obtained and any assumptions that may have been made.