MULTI-YEAR RESEARCH STRATEGY UNDER
THE PRODUCE AND IMPORTED
FOOD SAFETY INITIATIVE
The purpose of this document is to set forth a broad research strategy which, once implemented, will lead to substantially enhanced safety regulation of fresh fruits and vegetables in the United States. This research blueprint responds to the October 2, 1997, Presidential Produce and Imported Foods Safety Initiative (PIFSI), which directed Secretary Glickman of the Department of Agriculture (USDA) and Secretary Shalala of the Department of Health and Human Services (DHHS) to accelerate research in support of PIFSI. The Environmental Protection Agency (EPA) was directed to provide support in this initiative. The National Science and Technology Council (NSTC)/Office of Science and Technology Policy (OSTP), under the Executive Branch, was charged with policy coordination for this initiative, which includes the development of an integrated research plan for Fiscal Year (FY) 2000. Consistent with ongoing research planning efforts in response to President Clinton's National Food Safety Initiative (FSI) of May 1997, a component of the PIFSI directive involves inventorying all food safety research efforts within the Federal government towards (1) eliminating unplanned redundancies, (2) fostering communication and collaboration, (3) identifying the appropriate research focus to minimize risks posed by microbial pathogens on produce (fresh and/or minimally-processed fruits and vegetables), and (4) bringing to bear, in an integrated fashion, sufficient resources to carry out the research focus in a cost-effective manner.
This document is a result of interagency collaboration and provides a research strategy within the same broad categories given for research in the May 1997 FSI report to the President. An exception is the omission of the Food Handling, Distribution, and Storage section, which is combined with the Intervention section in this document. This broad research blueprint will provide the basis for a more detailed research plan to be prepared by each agency, as described in the closing section of this document.
Research provides the information and technologies essential to successful implementation of the guidance, inspection and compliance, education, surveillance, and risk assessment components of the FSI and PIFSI. Under these initiatives the Food and Drug Administration (FDA), within DHHS, and USDA share jointly the responsibility for developing a research program aimed at reducing disease caused by food borne microbes and their natural products. FDA's Center for Food Safety and Applied Nutrition (CFSAN) and USDA's Agriculture Research Service (ARS) are the designated leads for developing this research plan. CFSAN requested input, within DHHS, from the Centers for Disease Control and Prevention (CDC), the National Institutes of Health (NIH), the Center for Veterinary Medicine (FDA/CVM), the National Center for Toxicological Research (FDA/NCTR), and the Office of Regulatory Affairs (FDA/ORA), in developing this research strategy. ARS requested input, within USDA, from the Economic Research Service (ERS), the Food Safety and Inspection Service (FSIS), the Animal and Plant Health Inspection Service (APHIS), the Cooperative State Research, Education and Extension Service (CSREES), the Agricultural Marketing Service (AMS), the Foreign Agricultural Service (FAS), the National Agricultural Statistics Service (NASS), the Natural Resources Conservation Service (NRCS), and the Office of Risk Assessment and Cost Benefit Analysis (ORACBA). Contributions also have been received from additional agencies including EPA, the Department of Energy (DOE), the Department of Defense (DOD), and the National Science Foundation (NSF). Together, these groups are coordinating their resources and expertise to work collaboratively to enhance food safety, and are accelerating their efforts to reduce microbial risk associated with fresh produce.
Under PIFSI, the President directed the FDA and USDA to use existing authorities to issue guidance on good agricultural practices (GAPs) and good manufacturing practices (GMPs). Additionally, FDA and USDA are to provide "a plan on how to (1) improve the monitoring of agricultural and manufacturing processes abroad, (2) assist foreign countries to improve those practices where necessary, to prevent the importation of unsafe produce, (3) consider the best ways to target inspection and testing toward those areas where problems are most likely to occur, and (4) accelerate whatever food safety research is necessary to support" all of the above tasks. Implicit in this directive is the need to address issues regarding the microbial safety of produce that are specifically applicable to the needs of small businesses (farmers and manufacturers) and developing nations, through education, outreach, and technology transfer.
Currently, regulators, scientists, and the food industry are evaluating new methods of safeguarding the food supply from microbial hazards. One prominent approach is called Hazard Analysis Critical Control Point (HACCP), which is a proactive system of preventive controls of food production and/or processing at critical points that assure the safety of the food product. HACCP relies less on end-product testing and more on valid, safe processing plans and procedures, with appropriate verification. HACCP begins with the identification of relevant product-associated hazards, a process that is frequently based on the epidemiological association of a specific disease in consumers of that product. HACCP programs are based on in-depth scientific knowledge of the sources and methods for controlling pathogenic microorganisms that may contaminate a food. For fresh produce (fresh and/or minimally processed fruits and vegetables) that are produced in a myriad of ways to preserve important nutrients and sensory qualities, additional research is needed to provide the data for HACCP systems development. As accelerated research programs address the knowledge gaps related to the microbiological safety of produce, a general guidance document, based on the best available science, is presently being developed.
To fill knowledge gaps and to establish credible guidelines for fresh produce GAPs and GMPs, new and accelerated research must consider how recent insights into the evolution and promiscuous nature of microorganisms affect our understanding of the pathogenic phenotype, the mechanisms by which a microbe acquires resistance to antibiotics and/or to traditional barriers of food processing (e.g., heat and cold, preservatives, low pH, or lowered water activity), and the acquisition of virulence traits that allow survival and growth in the host. As human demographics change -- i.e., the human population continues to grow, people live longer, and modern health care allows continued life for those with chronic disease -- the immunity of an increasing portion of the population is compromised. Thus, any guidelines developed for control of pathogenic microbes must be based on a sound knowledge of the inherent variability in (1) the pathogenicity and virulence of the microbes and (2) the susceptibility of the human population. This knowledge is derived, in part, from epidemiologic studies of naturally occurring food borne disease, feeding studies, and other biomedical research.
The increased importance of the evolution of microorganisms is driven by several factors, most notably continual modernization of production/processing technologies, large scale production, and globalization of trade. Food, previously grown only in specific regions for consumption by the local population, is now transported, by various means, to a world population. Moreover, advances in agronomy and plant sciences have allowed crops to be grown in non-traditional regions. The microbial ecology of these foods, including pathogenic microbes and/or microbially-derived toxic contaminants (e.g., mycotoxins, biogenic amines, botulinal toxin, Staphylococcal enterotoxins), is thus relocated to new environments, and exposure to different populations and cultures occurs.
Regulatory responsibility for ensuring the safety of fruits and vegetables lies with the FDA, including setting standards for safeguarding human health and enforcing these standards in a scientifically and legally defensible manner. The EPA sets standards (tolerances) for pesticides and disinfectants in food, and FDA enforces those standards. EPA also sets municipal water quality standards and establishes microbiological and chemical criteria, methods, and indicators for surface waters potentially used for irrigation of produce and for the application of chemicals to produce. Furthermore, EPA promulgates regulations that restrict sewage biosolids application or disposal, which affects cropland fertilization uses. EPA also provides sewage discharge guidance, under the National Pollutant Discharge Elimination System (NPDES), for protection of shellfish growing areas. FDA has authority over bottled drinking water and sets quality standards in close consultation with EPA.
Both USDA and FDA support research to (1) develop the science upon which regulatory decision making and enforcement relies, and (2) assist industry in developing solutions to food safety problems. Within USDA, ARS conducts research in-house to provide the means to ensure the food supply is safe for consumers, FAS seeks opportunities for international cooperation and funds collaborative research between the United States and foreign scientists, ERS conducts intramural social science research on programs and policies relating to food safety, and CSREES supports extramural food safety research to university partners and other cooperators through competitive grants and mandated programs. These research programs often involve collaboration with industry. To complement in-house research, FDA partners (e.g., cooperative research and development agreements) with industry and/or academia through the establishment of consortia, such as the National Center for Food Safety and Technology (NCFST) in Summit-Argo, IL and the Joint Institute for Food Safety and Applied Nutrition (JIFSAN) in College Park, MD. These FDA consortia support educational and outreach programs mandated by the Public Health Service Act.
The research of FDA and USDA addresses many domestic and international food safety problems, including a plethora of technological practices, an array of animal and plant species and varieties, a range of climatic and regional differences, and a multitude of food products and consumer practices. To prevent duplication of effort both agencies have committed to a formal program of communication and collaboration that ensures effective utilization of available resources and transfers expertise and technology to appropriate venues. Both agencies and their research partners are committed to developing, in concert with industry and the public, an integrated Food Safety Research Plan consistent with the FSI and PIFSI objectives. The results of several meetings on research among the aforementioned agencies, between these agencies and industry representatives, and between these agencies and the public have identified the following priority areas: (1) improved detection methods; (2)resistance to traditional preservation techniques; (3) antibiotic resistance; and (4) intervention strategies (microbial ecology, production and processing factors, traditional and non-traditional treatments).
For fresh produce, there are concerns that the present methods do not adequately ensure food safety. For example, improved methods are needed to detect and quantify microbes in irrigation, washing, and sanitation waters and in conjunction with crop fertilization where biosolids or manures have been used. Moreover, tests that are cost-effective, precise, and rapid enough to detect contaminated foods prior to their entry into commerce will help ensure a safe food supply. The short shelf-life of fresh produce necessitates the development of rapid methods.
Research Activities to be Accelerated.
FDA, USDA and EPA will:
NIH and CDC will:
FDA and NSF will:
The development of improved detection methods encompasses several general analytical concerns, which may vary, depending upon the specific needs of industry, regulatory agencies, and action agencies. Rapidity of a method is relative to its need because the time required for detection may have an impact on either public health or the commerce of a product with limited shelf life. The sensitivity of a method is essential in determining, with statistical confidence, the level of a pathogen or its metabolite(s) in a commodity. The statistical validity of the sampling plan is also critical. Enumerative methods aid risk assessment by providing information pertinent to the elucidation of dose-response relations for susceptible populations. Methods that delineate the distribution of a contaminant in/on a commodity are also important for risk assessment. Recovery procedures must account for the possibilities that (1) the target pathogen may be stressed and thus inhibited by selective medium components or by the overall physiological design of the medium, (2) some of the myriad of foods to be analyzed have constituents that inhibit pathogen detection, and (3) differences in background flora among commodities and geographical regions can affect detection of the target pathogen. All of the above recovery concerns are exacerbated if the target pathogen is typically an infrequent and/or low-level contaminant of fresh produce.
Molecular methods, specific for certain virulence attributes of a pathogen or for genetic elements that affect pathogen evolution, may enhance the ability to detect known pathogens or predict emerging or "quick-change" pathogens. Methodology of this type, however, depends on knowledge of the pathogen (microbial pathogenesis, evolution, physiology) to determine exactly the molecular target for detection. For molecular methods to achieve their potential, effective procedures to remove, isolate and concentrate pathogens from produce(e.g., Cyclospora, Hepatitis A virus) may be required. It may also be necessary to amplify pathogen signals by enrichment/growth and/or to overcome matrix inhibition of molecular biology reagents. To resolve matrix inhibition problems, additional research on the chemical/nutritive components of food is necessary to support methods development.
Appropriate detection methods are an integral part of any program to assure food safety along the farm to table continuum. If the tests are to be effective, they must be applied at appropriate sites. Thus, development of methods to support GAPs and GMPs should be pursued, as well as validation studies to enhance technology transfer. Because methods development is a major focus of most agencies participating in FSI and PIFSI, research to support this need should be carefully coordinated to ensure effective collaboration rather than unnecessary duplication. An Interagency Methods Development Working Committee, composed of appropriate expertise from the various agencies, will be organized to enhance communication and information exchange, review ongoing projects, identify opportunities for international cooperation, and prioritize research needs.
Resistance to Traditional Preservation Techniques
Recent food borne outbreaks have emphasized that microbes are evolving to overcome traditional processing and preservation techniques. The emergence of acid tolerant Escherichia coli O157:H7 is a recent example that microbes adapt to and establish new niches. Thus, research is needed to determine how pathogens associated with fresh fruits and vegetables become tolerant to traditional food safety barriers.
Research Activities to be Accelerated.
FDA and USDA will:
Understanding these mechanisms will allow modeling of microbial pathogen emergence in the food supply, provide the science to support guidance (GAPs and GMPs), enable detection and classification of potential pathogens, and aid the development of new intervention strategies.
The development of antibiotic resistance during live animal production and the detection of resistant pathogens of domestic animal origin on produce point to a logical link between animals and produce as a possible source for transfer of resistant pathogens to humans. Research is needed to develop an understanding of the ecology of antibiotic resistant pathogens from animals, through produce and finally in humans where disease results. Current data provide evidence of the development of antibiotic resistant pathogens in both humans and animals following use of the antibiotic. However, the data do not provide a clear understanding of the mechanism of resistance development from both a physiological and molecular perspective. In addition to research describing development of resistant microorganisms from antibiotic administration in animals, research is also needed to characterize resistance that could occur from direct application of antibiotics in the field (e.g., controlling blight in fruit trees).
Research Activities to be Accelerated.
CDC, FDA, and USDA will:
FDA, USDA, and EPA will:
The characterization of resistance development is important to our understanding of the transfer of antibiotic resistant pathogens from the carrier animal to other animals and from manure to animal-derived food and produce. This research will examine resistance development at the genetic level such that resistant organisms can be effectively traced from detection in a particular commodity back to their ultimate source. Enhanced understanding of the molecular basis of antibiotic resistance will aid the development of prevention/intervention strategies designed to eliminate or minimize the presence of resistant pathogens in/on food.
Practical and economical intervention methods are needed to prevent microbial contamination of fruits and vegetables both pre- and post-harvest. Intervention methods are also needed to prevent contamination that may occur in retail or wholesale distribution (including transportation), in food service establishments, and in the consumer's home. Traditional and alternative intervention strategies that inactivate microbes by different physiological mechanisms will be refined or developed to (1) minimize the emergence and occurrence in food of pathogenic microorganisms resistant to antibiotics and traditional preservation technologies, (2) provide flexibility to industry in meeting guidance, and (3) facilitate science-based safety decisions by FDA, towards expediting the food additive petition approval process. The development of pathogen reduction practices will focus on practical methods that may be economically adopted by small and large producers, both domestically and in foreign countries, through technology transfer.
Research required for development of effective intervention strategies to prevent pathogen contamination of fresh fruits and vegetables will include:
Details regarding each of these areas are provided below.
Microbial Ecology/Environmental Factors
Numerous environmental factors can contribute to pathogen contamination of fresh produce. Potential vectors for many microorganisms, such as Cyclospora, are not well understood. Manure has been suspected as a source of pathogens on contaminated fruits and vegetables. By minimizing the colonization of the gastrointestinal tract of animals by human pathogens, the shedding of viable pathogenic microorganisms in manure can be reduced. Practical and economical pathogen reduction processes (e.g., composting), which are suitable to farm size and manure production levels and that have well-defined process parameters, are needed. Wherever water comes in contact with produce its source and quality dictate the potential for pathogen contamination. Irrigation and surface runoff waters can be sources of pathogenic microorganisms that contaminate fruits and vegetables in the field. Likewise, contaminated water used during processing can be a source of pathogens on produce.
Research Activities to be Accelerated.
USDA, FDA, CDC, and EPA will:
FDA will:
Microbial Ecology/Plant-Microbe Interactions
Development of effective intervention strategies for reducing or eliminating microbial pathogens on fresh fruits and vegetables cannot be based solely on identification of sources of contamination; ecological interactions between the pathogenic and natural bacterial flora associated with fresh produce must also be considered. Control of pathogens on fresh fruits and vegetables by manipulation of the ecology of food production and processing environments requires a firm understanding of the genetic, biochemical, and physiological factors affecting microbial presence, persistence and proliferation on these foods. Information gained from such studies will be used to guide application of specific intervention techniques and may lead to the development of alternative, novel treatments to reduce contamination.
Research Activities to be Accelerated.
FDA and USDA will:
FDA, USDA, and NIH will:
Production and Processing Factors
Adverse production or processing conditions may result in contamination of fruits and vegetables with molds and human pathogens or may affect the state of microorganisms such that they survive decontamination interventions. Reducing the consumers' exposure to pathogenic microorganisms on fresh fruits and vegetables can be achieved only by addressing production and processing factors throughout the entire system. Production of structurally sound, unblemished fruits and vegetables that are less likely to support mold and pathogen growth is important for helping to prevent microbial contamination. Because natural barriers to microbial contamination are broken when produce is harvested or minimally processed (e.g. fresh cut), post-harvest practices involving transport, handling, packaging, storage, and preparation provide opportunity for contamination by pathogens that may survive or multiply on the product. Intervention methods are needed to prevent the persistence, propagation, and recontamination by pathogens post-harvest. Proper handling procedures and the efficacy of rinse and wash procedures must be investigated to help distribution, retail and food service operations, as well as consumers in the home, achieve safer food.
Research Activities to be Accelerated.
USDA will:
FDA and USDA will:
Traditional and Non-traditional Treatments
Traditional food safety treatments involving heat or cold, low pH, low water activity and disinfectants, although somewhat effective for certain produce commodities, are also sometimes ineffective or inappropriate for decontaminating others, at least when administered at levels required to maintain sensory quality. For example, traditional heat pasteurization, while effective for many food matrices, is impractical for use on perishable commodities. Research is required to establish and optimize the effectiveness of traditional physical and chemical treatments currently employed during minimal processing of produce. Moreover, new interventions are needed for fresh produce that preserve quality appearance, preserve sensory properties, and maintain nutrient content, while providing pathogen control. Such interventions must overcome constraining factors, such as the presence of microorganisms within biofilms, cracks or other inaccessible sites. Investigation of these alternative control strategies, including physical treatments such as pressure, high intensity light, irradiation and modified atmospheres, may result in effective methods of reducing pathogens. New intervention strategies involving chemical treatments (e.g., novel sanitizing solutions, surfactants, and natural antimicrobial agents) or biological treatments (e.g., bacteriocins, competitive microbial inhibition, microbial growth stimulants) will also aid pathogen reduction.
Research Activities to be Accelerated.
FDA, USDA, EPA and DOD will:
Risk Assessment and Food Safety Research
As described in the May 1997 FSI Report to the President, carefully formulated risk assessments are based on the best available data and scientific analyses generated from research. In turn, risk assessment guides research directions by describing the data gaps that create the most uncertainty in the risk assessment. In recognition of this close relationship between research and risk assessment, an interagency Risk Assessment Consortium (RAC), composed of microbial risk assessors and scientists from applicable federal agencies (FDA,USDA, EPA, Department of Commerce, CDC, NIH) and their partners, has been established at the Joint Institute for Food Safety and Applied Nutrition (JIFSAN), College Park, MD.
The RAC is formally tasked with coordinating risk assessment research priorities, eliminating redundancies of effort, and encouraging multi-disciplinary research efforts. The RAC functions will include developing a scheme for setting methodological research priorities, serving as a clearinghouse, and fostering and augmenting critical research projects.
Individual food safety agencies are emphasizing research in the following areas:
The accelerated research focus in support of the Presidential Produce and Imported Food Safety Initiative, agreed upon in this document, will be implemented by each agency in a transparent manner. Each agency will identify, by June 15, 1998, specific research projects to be initiated, expanded, or redirected during FY 1998, including the scientific and fiscal resources that will be provided in support of the research. In addition to these specifics for FY 1998, each agency will provide their strategic plans, which will relate research program changes, resource redirections, and resource deficiencies for FY 1999 and FY 2000. This information will be transmitted to DHHS and USDA. These organizations will serve as the leads for consolidating information related to implementation. DHHS and USDA, in collaboration with NSTC/OSTP, will use this information to identify additional priority food safety research areas that are not currently addressed in FSI/PIFSI. This mechanism, in turn, will be used to develop future food safety initiatives and their budgetary requirements.
Hypertext updated by dms 2001-OCT-10