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Spring 2008
The Center for Food Safety and Applied Nutrition (CFSAN) maintains a comprehensive intramural research program that provides the cornerstone for regulatory decisions, enforcement activities, and the development, implementation or evaluation of CFSAN policies. Research knowledge plays a major role in reducing levels of food-borne illness in the United States and helps to ensure food safety and food defense, the safety of cosmetic products, and enhance the ability of consumers to make sound nutrition choices. Together with our academia and industry consortia research partnerships, and our extramurally funded research activities, CFSAN's overall research program is structured to play a vital role in helping the Center fulfill its public health mission.
CFSAN's intramural research program provides the basis for nutrition labeling regulations and guidance, identification of foodborne pathogens, toxins, and select agents, and the development of mitigation and prevention strategies. In addition, the research provides the scientific basis for regulating the food producing and processing industries to ensure a safe and nutritious food supply from farm-to-table. All intramural research projects have a finite lifespan that may last up to three years. CFSAN uses a life-cycle approach for these research projects that provides an ongoing opportunity to adjust research activity focus and objectives.
This document is a listing of the currently active intramural research projects being conducted by CFSAN researchers. The projects are grouped by the CFSAN Program Priorities (Cosmetic Safety, Dietary Supplement Safety, Improving Nutrition, Food Safety and Food Defense) and are listed in order by project number. This listing is provided to promote communication, interaction, and collaboration with all of our stakeholders: consumers, sister agencies, and our partners in industry and academia. We appreciate your interest and can provide you with more information about the research efforts identified.
Stephen F. Sundlof, D.V.M., Ph.D.
Director, Center for Food Safety and Applied Nutrition
For Additional information regarding an individual project please send an e-mail inquiry to: mark.wirtz@fda.hhs.gov or diana.hao@fda.hhs.gov
The Office of Cosmetics and Colors receives reports of consumer adverse reactions to cosmetic products. Products that appear linked to particularly severe or to an unusual number of adverse reactions are evaluated in an effort to determine the cause of the reactions. Analysis of the components in raw materials or of contaminants in finished products is typically conducted. When necessary, methods development work for specific components is done to support these analyses. When investigations indicate an adulterated product, the laboratory data helps support the basis for regulatory action. This work helps ensure the safety of cosmetics and cosmetic ingredients.
Retinyl palmitate is widely used in cosmetics which are applied to sun-exposed skin and there are reports that, in some individuals, retinoids can increase the skin's sensitivity to the sun. One explanation is that light interacts with retinyl palmitate to cause cellular damage. In this study, we are examining the photosensitizing potential of retinyl palmitate in two biologically relevant model systems: liposomes and mouse embryonic fibroblasts, using spectroscopic methods to detect free radicals. This work will improve our understanding of retinoids and their effects on the skin's sensitivity to the sun and provide information useful for evaluating the safety of retinoid-containing cosmetics.
There is considerable interest in delivering a variety of materials (drugs, vaccines, cosmetics) by using nonoparticle based liposomes and vesicles containing these materials to penetrate the skin. The ability of such vesicles to enhance the skin penetration of fluorescent dyes and retinol is being studied using human and pig skin to better understand their effectiveness in enhancing skin penetration of active or toxic ingredients. Analytical techniques in this study will include permeability measurements, confocal microscopy and small-angle neutron scattering. Results should help assess the potential of these vesicles and liposomes to enhance the absorption of possibly active or toxic ingredients that may be present in cosmetic products.
Periodically there are reports in the news of dangerous levels of lead in lipsticks with the implication that the lipstick, and therefore the lead, is being ingested. We are developing and validating a method for measuring the amount of lead in lipsticks. The method will permit FDA to make an independent evaluation of the hazard suggested by media reports.
Bone black, certifiable as D&C Black No. 3, is a new color additive listed in 21 CFR Part 74.2053 for use in eyeliner, eye shadow, mascara, and face powder. This effort is designed to develop, validate, and publish a method for quantifying silica in D&C Black No. 3. The method will be used to support FDA certification of new batches of D&C Black No. 3.
Reference materials are needed in the development of new analytical methods for the enforcement of specifications, described in the Code of Federal Regulations, for indigoid color additives. The reference materials also provide a means for the identification, characterization, and determination of impurities that are not specified. We are preparing reference materials for the analysis of indigoid color additives. The reference materials and methods will be used to support FDA certification of new batches of FD&C Blue No. 2 and D&C Blue No. 6 and chemistry reviews of petitions for new indigoid color additives.
There is concern about the potential for nanoparticles in cosmetics to increase skin absorption of ingredients that are considered safe in current cosmetics. In this study polyamidoamine dendrimers are being formulated in an oil-in water emulsion representative of a nanoparticle containing cosmetic product to examine the ability of these dendrimers to penetrate skin. Absorption in frozen skin sections is being examined by laser scanning confocal microscope to visualize the location of the applied dendrimers. Dendrimers that appear to penetrate skin will be examined for their ability to enhance the skin penetration of model compounds. This information will help ensure the safety of cosmetic products using nanoparticle based materials.
Toxicity measured in an animal model system indicates exposure to phthalate esters is of particular public health concern because of its reproductive effects. A survey of consumer cosmetic products for phthalate esters was conducted by the FDA in 2002 and published in 2006. Since that survey the FDA has observed the reformulation of some cosmetic products to remove phthalate esters. In this study a representative set of 50 consumer products will be analyzed to determine if they have been reformulated to reduce or remove phthalate esters. The survey will provide current data on the use of phthalates esters in cosmetic products and help reevaluate human exposure to these chemicals.
Changes in patterns of exposure to permanent makeup inks and reports of adverse reactions to certain shades of permanent makeup ink have led to increased safety concerns about these products. Enforcement activities have been hindered by the need for analytical methods to identify possibly toxic components in these products. This project is developing rapid, in vitro screening methods to identify permanent makeup inks or components of these inks that elicit toxicity, including phototoxicity. These methods are expected to provide data that will assist FDA in removing unsafe permanent makeup inks from the market place and help industry to safely formulate their permanent makeup ink products.
There is little safety information regarding the use of nanomaterials in cosmetics. However, nanomaterials are currently being used in some cosmetic products. In this study the in vivo and in vitro skin penetration of cosmetic formulations incorporating three different sized dendrimers, a nonomaterial, will be investigated using the hairless guinea pig. The study will see if dendrimers can penetrate the skin and possibly increase the skin penetration of other cosmetic ingredients. If this is the case, further investigation will be undertaken to evaluate the possible impact additional exposures may have on human health and help Agency efforts at ensuring cosmetic product safety.
Current analytical methods used for the enforcement of specifications, described in the Code of Federal Regulations, for the analysis of organic components in listed color additives need to be updated. We are developing and validating updated methods using high-performance liquid chromatography technology that incorporate a more environmentally friendly technology. The methods will be used to support FDA certification of new color additive batches and will be applied to investigations of unlisted color additives of regulatory concern.
Current analytical methods used for the enforcement of specifications, described in the Code of Federal Regulations, for the analysis of inorganic elements in listed color additives need to be updated. We are using x-ray fluorescence (XRF) spectrometry to identify inorganic elements and atomic absorption spectrometry to quantify low levels of identified elements. We are also developing and validating improved XRF methods for determining elements in certifiable color additives that provide better accuracy and lower limits of detection. The methods will be used to support FDA certification of new color additive batches and will be applied to investigations of unlisted color additives of regulatory concern.
The technique of mass spectrometry is needed for the analysis of unknown impurities in color additives. We are applying mass spectrometric techniques to identify, characterize, and quantify various impurities that are sometimes found in color additives submitted for certification and that are not specified in the Code of Federal Regulations. Results from this project will facilitate development of new analytical methods for the enforcement of CFR specifications by FDA's Color Certification Branch and will provide support for the chemistry review of petitions for new color additives.
One of the roles of the FDA's food safety program is to monitor for the presence of pesticides in foods. However, because there are thousands of pesticides and food types, developing methods to identify, quantify, and confirm pesticides presents many challenges. This research involves improvement of current procedures for pesticide analysis and establishes validated methods to be used for regulatory monitoring and surveillance programs. The outcome of this work should help ensure safer food products, such as fresh produce, and dried botanical dietary supplements.
Dietary supplements are increasingly used as part of diets. Supplements that are gaining popularity are those with antioxidant claims. Antioxidant activity and pro-oxidative damage are biomarkers that are used to assess the safety of commercial dietary supplements. Electron spin resonance (ESR) techniques are being used to determine if certain dietary supplements can scavenge and/or generate free radicals in biological systems. These studies may enhance our understanding of potential benefits or human health effects of dietary supplements.
Dietary supplements may contain harmful botanical substances or chemicals. Although these supplements are widely available in retail outlets, obtaining authentic botanical reference materials and chemical standards for many important botanicals is extremely difficult. To assist FDA with the safety assessment of botanical dietary supplements, we have developed a collaborative effort with the U of Mississippi to authenticate botanical reference materials, produce and characterize chemical standards from botanicals and to develop analytical methods for the analysis of botanical dietary supplements. Results of this project will enable the FDA to better respond to possible hazards presented by these products.
Molds that produce mycotoxins that adversely affect human health may grow on food crops and plants used as ingredients in dietary supplements. Some mycotoxins have been associated with carcinogenesis. There are mycotoxin detection methods for testing botanical dietary supplements that need to be validated for regulatory purposes. This effort is trying to develop and validate analytical methods for several mycotoxins of regulatory concern so they can be used by the Agency and industry to further ensure the safety of botanical dietary supplements. The method will provide reliable data about the amounts of mycotoxins present in botanical based supplements that pose public heath concerns.
These toxic elements occur naturally in the environment and they may contaminate dietary supplement ingredients, or supplements may become contaminated during the manufacturing process. This research is attempting to improve analytical methods for these toxic elements using microwave assisted acid decomposition and inductively coupled plasma mass spectrometry. This approach should provide faster, more sensitive and specific determination of these toxic elements in dietary supplements, and improve FDA's ability to identify dietary supplements that may contain potentially harmful levels.
The market for botanical dietary supplements has grown rapidly during the last 15 years. Use of newly introduced botanical ingredients has often outpaced an adequate scientific understanding of the ingredients themselves. The development of methods for identifying potentially bioactive constituents in fresh plant material and in concentrated extracts is expected to improve the overall quality and safety of botanical dietary supplement ingredients.
The mandate to label food products with their trans-fats content has led to the need for more sensitive and accurate trans-fats measurement methods. Trans-fats are found naturally in some foods but the major source of trans-fatty acids in the American diet occurs from the partial hydrogenation of vegetable oils. Different foods containing partially hydrogenated vegetable oils have different levels of trans-fats and oils. We are developing a 5 minute procedure using infrared spectroscopy to measure trans-fatty acids, which will be validated in an international collaborative study. If successfully validated, it will become an official method for regulatory purposes to ensure accurate trans-fat label information.
Many foods contain components that have a biological activity when eaten. Examples include antioxidant vitamins such as vitamins E and C, some flavonoids derived from fruits and vegetables, and isoflavones found in soy-containing foods. Little is known about the stability of some of these components in food and how their stability affects their biological activity. In particular this effort is studying the effects of heat processing on the stability of these bioactive food compounds to improve our understanding of potential changes in their effectiveness and safety.
FDA is responsible for providing consumers with information about packaged foods that is accurate and not misleading. Because there is a well established scientific link between consumption of trans-fat and the risk of coronary heart disease, FDA now requires that the amount of trans-fat be declared on the Nutrition Facts label of packaged foods. This study is assessing how consumers make decisions about the food products that include label information about trans-fat, and is evaluating the usefulness of adding label footnotes about recommended intake levels of trans-fats, saturated fats, and cholesterol that may improve consumer judgments of the products in ways that benefit consumer health.
FDA is responsible for providing consumers with information about packaged foods that is accurate and not misleading. There is a scientific link between consumption of trans-fat and the risk of coronary heart disease. A number of label claims about the trans-fat content of products now appear on the panels of packaged foods. These claims may better inform consumers about the nutritional characteristics of these products, but may lead consumers to incorrectly judge the benefits of these products. This study is examining the impact of trans-fat free and reduced trans-fat label claims on consumers' food product choices. FDA can use this information to evaluate regulatory and policy options for these label claims.
Regulated claims on food products must be truthful and not misleading. FDA authorizes health claims when there is significant scientific agreement that eating a product may decreased the risk of developing a disease. FDA also allows qualified health claims for nutrients when there is some scientific evidence but it fails to constitute significant scientific agreement. Consumers may form mistaken judgments about the qualified health claims of products and the level of scientific support for non-specified health benefits, product quality, and product safety. This study evaluates consumer reactions to different qualified health claims. FDA can use this information to evaluate regulatory policy options for qualified health claims.
There are gaps in our understanding about the health and nutrition practices of pregnant and breastfeeding mothers. This study is obtaining important survey information about infant and maternal health and nutrition. Each survey participant completes questionnaires twice while she pregnant and ten times during the first year of her baby's life. The results from these multiple questionnaires provide valuable information that can be used to inform new policies aimed at promoting maternal and child health. Also, the findings can be used by educators to develop new messages and materials to inform these women about better nutrition for themselves and safe and healthy feeding practices for their young child.
Improved methods for analyzing total trans-fat content are needed for FDA's food labeling compliance programs. Monounsaturated fatty acids (MUFAs) are the most common source of trans-fatty acids in partially hydrogenated oils and fats. This work will focus on the development of MUFA reference materials and procedures for synthesizing mixtures containing all of the cis/trans isomers of MUFAs and polyunsaturated fatty acids (PUFAs). GC analysis of the mixtures will provide elution patterns that can help improve determination methods of total trans-fat content. The increased availability of GC reference standards will strengthen FDA's compliance programs for accurate labeling of trans-fat content of foods and dietary supplements.
The thyroid gland takes up iodide from the bloodstream and incorporates it into hormones that are essential for human metabolic processes and neural and brain development in early stages of life. The industrial chemical contaminant perchlorate and the food component thiocyanate, which are found in certain vegetables and whole milk, may seriously interfere with iodide uptake. This project is developing an analytical method to measure iodide, perchlorate, and thiocyanate in foods where they are likely to occur. Findings should provide useful exposure data for making iodide deficiency health-risk assessments.
Listeria monocytogenes (LM) causes approximately 2,400 illnesses per year in the US, including 400 deaths. In this project, modeling tools are being developed to help predict the affect on LM growth after foods have been pretreated with mild heating and then packaged under carbon dioxide to inhibit subsequent LM growth. Better knowledge of this pathogen's ability to compete with the natural spoilage microbes that are present in foods will improve our ability to predict LM growth in commercially-packaged foods. This information will be used to help guide industry in its efforts to produce safer ready to eat packaged foods for consumers.
An estimated 11 million people in the United States suffer from food allergies. FDA requires that all foods containing one of the eight major food allergens be appropriately labeled. There is currently a lack of validated rapid analytical methods for detecting the presence of some of these allergens in food. The research being undertaken will evaluate commercial test kits for detecting allergens in food and facilitate the validation process for those kits deemed useful. Research is also being done to develop rapid inexpensive methods that handle large numbers of samples while testing for several allergens simultaneously in food. These methods will help support the agency's compliance activities.
For over 100 years the FDA and its predecessor agencies have protected the public food supply from contamination by insects, rodents, rodent feces, yeast, mold, etc. Today CFSAN is continuing to study the public health risk posed by these various filth elements. In addition to maintaining its traditional analytical abilities to test for these kinds of materials, additional efforts are being made to develop and apply current technology to test for filth and extraneous material. This information will be shared to help industry identify and control the various filth elements that may contaminate foods and dietary supplements.
FDA's ability to protect the food supply is enhanced through the development of methods that rapidly test for multiple foodborne pathogens. DNA microarray technology is a method that can simultaneously test for multiple pathogens, but this technology can be cost prohibitive. We have developed a label-free DNA microarray hybridization detection protocol for pathogenic bacteria that uses cost effective infrared (IR) spectroscopy to detect DNA hybridization reactions. If successful, this method will be able to identify pathogen DNA from non-pathogen DNA. The method will be used to develop assays for the rapid detection of pathogenic foodborne microorganisms.
Molds and fungi have a significant impact on food spoilage. Some molds produce fungal toxins or mycotoxins that are a public health concern in both humans and animals. This project is evaluating the performance of different methods for measuring the numbers of molds and yeasts in foods. Each method is being tested against an established FDA official BAM method using naturally-contaminated food samples from various food commodities. Improved detection and enumeration of toxin-producing fungi in foods may serve as a useful indicator of quality, help guide the removal of contaminated foods, and decrease the incidence of fungal toxin related foodborne illness.
There are close to 2,000 pesticides used worldwide and approximately 700 pesticides registered for use in the U.S. The FDA only screens for 300-350 pesticides in domestic and imported foods. There is a need to develop new and improved analytical methods to expand this coverage. Also a new approach for detecting pesticides or persistent organic pollutants is being developed. Pesticides and organic pollutants will be measured with high specificity and sensitivity in a single chromatography/mass spectrometry determination assay instead of needing up to 6 assays. This work will improve detection of potentially hazardous chemical contamination problems in foods.
The United States and Canada have experienced sporadic illnesses and outbreaks of listeriosis associated with the consumption of cheese, including soft-ripened cheese. This joint FDA/Health Canada risk assessment will evaluate the effect of factors such as the microbiological status of the incoming milk, the various cheese manufacturing steps, and conditions during distribution and storage, on LM levels in the final product and on the overall risk to the consumer. This risk assessment will also evaluate the effectiveness that various process changes and intervention strategies may have on reducing human illness.
Improved analytical methods are needed for the enforcement of specifications, described in the Code of Federal Regulations, that limit the amounts of intermediates and unsulfonated impurities in certifiable color additives. We are developing new methods using high-performance liquid chromatography technology to be used to support FDA certification of new food color additive batches.
Food allergies affect an estimated 10-12 million people in the U.S. Consumers with food allergies rely on food labels to disclose the presence of allergenic ingredients. However, allergens can be inadvertently introduced into food due to ineffective cleaning of equipment used to manufacture food. This project is studying methods for cleaning food processing equipment and methods for measuring the effectiveness of cleaning procedures. This project should help lead to ways that avoid allergens from being transferred into food from allergen contaminated processing and packaging equipment, and thus help protect the health of allergic consumers.
The emergence of pathogens in products such as powdered infant formula, almonds and dry spices has raised awareness of microorganism contamination in dry ingredients. Traditional thermal technologies are not suitable for adequately decontaminating dry food materials. This project is investigating the effectiveness of decontaminating dry ingredients during processing using microwave heating and low temperature thermal plasma, an emerging technology. If successful, these technologies could be used as a means of reducing microbial pathogens in dry ingredients to improve their safety.
Viruses cause nearly two-thirds of all foodborne illnesses in the U.S. yet insufficient food safety research is done on detecting and controlling these viruses. This effort is designed to expand our capability to perform foodborne virus studies and develop data on ways to reduce contamination by foodborne viruses. Studies are to be focused on ways to decontaminate foods, especially fresh fruits and vegetables, using chemical or physical treatments that can inactivate foodborne viruses and thus improve the safety of these foods.
Aquaculture products are an important food source. Diseases occur in farm-raised fish or shellfish that often require drug therapy. Regulations governing the use of drugs in animals used for food vary from one country to the next. Products imported into the United States must comply with applicable federal and state regulations. This project is trying to develop reliable and practical methods for monitoring drug residues in aquaculture products. Validated methods will become available for use by compliance and surveillance programs to ensure food safety.
Ciguatera fish poisoning (CFP) is caused by consumption of finfish contaminated by ciguatoxins. It is a disease of global distribution. The lack of efficient detection methods for identifying ciguatoxin contaminated fish prior to its sale to consumers is interfering with the formulation of a more effective management and regulatory strategy. This project is developing rapid screening and confirmatory methods for ciguatoxins in seafood. This will help support the formulation of better management guidelines and advance CFP prevention and monitoring programs.
Scombroid fish poisoning is a major seafood safety problem caused by bacteria producing histamine and other biogenic amines during the natural decomposition of fish after they are dead. These toxic decomposition products may go undetected before the seafood is sold or eaten. This project is examining the chemical changes in seafood that causes toxicity and is developing electronic sensors (electronic nose) to measure changes in volatile components that can serve as a way to detect the accumulation of toxic decomposition products. The development of this electronic nose type of instrument will increase food safety by improving detection of seafood decomposition.
Neurotoxic shellfish poisoning (NSP) is an illness caused by consuming shellfish contaminated with algal brevetoxins. Harmful algal blooms producing brevetoxins occur periodically in the Gulf of Mexico and along the southeastern seaboard of the U.S. Prevention of NSP is achieved by monitoring the environmental for these blooms and by mouse bioassay of affected shellfish. However, the mouse bioassay is recognized as inefficient and non-specific. This project is developing and validating instrument based methods to replace the mouse bioassay and improve the management of NSP.
Many foods contain compounds that interfere with most DNA based identification techniques, such as DNA microarray hybridization technology. This effort is trying to develop a high throughput microarray assay using infrared spectroscopy detection technology to simultaneously identify a wide variety of pathogenic bacteria directly in different foods. The ability to have one platform that can simultaneously detect many different foodborne microbial pathogens would significantly improve our food analysis capabilities, and thus enhance efforts to protect consumers by reducing their exposure to foods found to be contaminated with these pathogens.
To manage and reduce the impact of widespread foodborne outbreaks it is necessary to quickly distinguish local outbreaks of illness from more widespread outbreaks that are unfolding on a regional or nationwide level. DNA fingerprinting techniques like PFGE (pulsed field gel electrophoresis), are used to match the DNA from bacteria found in patients with those found in food samples and environments like food processing facilities. PFGE matches alert federal agencies tracking such outbreaks. Early detection in turn helps to limit further distribution of suspect or contaminated foods and thus reduces the number of consumer illnesses during widespread foodborne outbreaks.
During foodborne disease outbreaks DNA fingerprinting techniques are often used to establish a link between the bacterial pathogen isolated from patients and suspected food and environmental sources. Current typing methods may require considerable time and effort, and results can vary from laboratory to laboratory. This research is evaluating an alternative analytical technique, Multi-Locus VNTR (variable number tandem repeat) Analysis or MLVA, which should be quicker, more reproducible and less expensive. The method would provide an additional means of characterizing bacterial pathogens and help improve public health response to foodborne disease outbreaks.
Paralytic shellfish poisoning (PSP) is the human illness associated with the consumption of seafood contaminated with toxins produced by certain algae (e.g. Alexandrium fundyense). Shellfish harvesting is banned when toxins exceed a safe action level. More data is needed to better manage the shellfish PSP biotoxin risk in offshore New England waters. This project is sampling surface water, subsurface waters and shellfish over a wide area and under varying conditions, to assess algal populations and toxin distributions in an effort to develop a comprehensive regional-scale understanding of these algal blooms and associated shellfish toxicity.
Enterohemorrhagic Escherichia coli (EHEC) of serotype O157:H7 remain the main pathogen that causes EHEC infections worldwide. Current EHEC detection assays are specific only for the O157:H7 serotype. Increasingly, atypical strains of O157:H7 and other EHEC strain serotypes are being isolated and implicated in foodborne illness. This project is further characterizing atypical O157:H7 strains as well as non-O157:H7 EHEC strains in an effort to identify unique DNA sequences that can be used for their detection. The ability to detect a wider range of EHEC strains should enhance our ability to detect more EHEC contaminated foods and thus better ensure food safety.
FDA uses reference materials to help confirm the quality of analytical results for toxic elements such as arsenic, cadmium, mercury, and lead in foods. The diversity and compositions of currently available reference materials are inadequate for the variety of foods the FDA investigates for toxic elements. This research is attempting to develop a reference material prepared from tuna that contains toxic elements at levels relevant to FDA's monitoring activities. Availability and use of this reference material will provide FDA laboratories with a means to demonstrate the quality of analytical results used by the agency to enforce regulatory decisions.
Shigella species remain a leading cause of outbreaks due to the consumption of foods contaminated with a bacterial pathogen. Improvements in PCR technology, and the commercial development of chromogenic indicator agar media and selective enrichment broth, have provided the opportunity to combine classic bacteriological methods with DNA based real-time PCR detection methodology. Integration of these methods into one protocol may provide Federal agencies, including the FDA, with a more reliable Shigella isolation and detection protocol to ensure the American public of a safe food supply.
Volatile Organic Compounds (VOCs) occur in foods as natural components, as processing contaminants, or as food packaging materials contaminants. Some VOCs may be carcinogens or neurotoxins. For example, benzene is a human carcinogen that can form in some beverages that contain both benzoate salts and ascorbic acid. The occurrences of benzene and other VOCs of concern need to be monitored so the Agency can implement the necessary regulatory steps to minimize exposure. This project is developing methods to determine VOCs in foods. Once validated, they will be used to monitor VOC occurrence in foods and help evaluate health risks from these sources of VOC exposure.
The presence of the toxic element mercury (Hg) in food is a significant public health issue. There is a need to develop and validate an independent method to confirm the results from the routine Hg monitoring technique that uses cold vapor atomic absorption spectrometry. Confirmatory methods ensure the accuracy of analytical results used for regulatory purposes. This research is trying to use instrumental neutron activation analysis (INAA) as a confirmatory method of measuring the level of Hg in food. This will ensure that FDA's regulatory decisions and consumer advice are based on scientifically sound analytical measurements of mercury.
Infectious diseases caused by viruses have been associated with the consumption of fresh produce. This project is trying to establish protocols for the efficient recovery of viruses from contaminated produce, and to gain more knowledge about viral survival during produce storage and processing. The availability of efficient virus detection methods will help enhance produce safety by improving our ability to identify fresh produce contaminated with foodborne viruses that cause human illness.
Listeria monocytogenes (LM) is frequently recovered from ready-to-eat seafood such as smoked fish and picked crabmeat. LM is known to cause serious human illnesses, especially among pregnant women. The presence of this organism in final product is usually the result of cross-contamination from the food processing environment. This project is evaluating promising new antimicrobial treatments, such as processing seafood using hydrostatic pressure, to determine their effectiveness in reducing/eliminating LM from ready-to-eat food or food processing areas to improve seafood safety.
Noroviruses are the primary cause of non-bacterial foodborne illness in shellfish consumers. Shellfish can carry these viruses if their harvest waters are contaminated by municipal wastewater or certain non-point wastewater sources. The sanitary quality of shellfish and shellfish harvest waters are partly determined using fecal coliform bacteria. But using fecal coliforms may not always be a reliable indicator of the presence of pathogenic viruses. This study is investigating the use of other microorganisms as indicators of the presence of noroviruses, enteroviruses, and hepatitis A virus in shellfish, shellfish harvest waters, and various wastewater sources to help improve seafood safety.
USDA and FDA are conducting a risk assessment for highly pathogenic avian influenza (HPAI) virus associated with the consumption of poultry meat, shell eggs and egg products. Most strains of the virus cause mild disease in infected birds and do not pose a threat to human health. HPAI causes a more severe disease in birds and may infect humans. Human HPAI cases are likely caused by inhalation of infective droplets during contact with live or dead birds. Currently no confirmed data link the consumption of poultry products to human illness. However unlikely, it is important preparations be considered to address the possibility that the food consumption exposure route for humans may exist.
The FDA uses several models to evaluate the migration of chemicals from food packaging materials. In these models, both diffusion (D) and partition (K) play a crucial role in determining the level of migration from a food packaging material. There is a significant data gap on D and K values for organic compounds in PET and nylon polymers due to their inherent low permeability. Studies are being performed to determine D and K values for the migration of various organic compounds. This information will help improve FDA's migration database, validate existing migration models for use in regulatory reviews, and provide better dietary intake estimates for these organic compounds.
The ability to type and differentiate bacteria is important for epidemiological investigations of bacterial outbreaks in food. We are developing a new method for bacterial differentiation based on direct measurement of the bacterial protein profiles. This method will complement genetics based testing methods, and additional details about protein biomarkers may offer insights into bacterial pathogenicity and antibiotic resistance. We are evaluating this method with a set of closely related strains of Salmonella and comparing the results to other bacterial differentiation methods. This approach should identify differences between closely related bacteria and provide better information during outbreak investigations.
Food allergies are a public health concern, affecting 1-2% of adults and 5-10% of children. There are rapid screening methods for allergens in foods. Concerns over false positives in these methods require sensitive and specific confirmatory tests. We are developing advanced bioanalytical mass spectrometry methods for a range of food allergens, as was previously done for peanut allergens. We are expanding the range of allergens that can be analyzed by identifying appropriate allergen markers for wheat, milk, eggs, soy and tree nuts. The result will provide a suite of analytical methods to confirm the presence of allergens in foods.
Immunological and DNA based tests can be used to rapidly and directly identify pathogens in food. This effort is trying to identify possible virulence factors and evaluate their potential contribution to the illnesses caused by these two foodborne bacterial pathogens. Once identified it may be possible to use these virulence factors to develop rapid methods for identifying food contaminated with these pathogenic bacteria. The availability of such tests should ensure a safer food supply by helping to divert pathogen contaminated food from the marketplace.
Some foods are processed to eliminate bacteria that have the ability to cause human illness. Different types of bacteria require different levels of treatment during food processing. Heating has long been the primary way that foods are processed but new types of processing methods are being developed that are able to prepare foods that are just as safe. The developed Food Safety Objective framework allows new processing methods to be developed to produce foods that are equally as safe as those prepared using the traditional heat base processing while maintaining excellent quality.
The ingestion by babies of Enterobacter Sakazakii contaminated powdered infant formula can cause neonatal meningitis, bacteremia and necrotizing enterocolitis, with mortality rates of 40-80%. Little is know about the virulence related genes in E. sakazakii. As a result, it is not currently possible to use unique virulence related DNA sequences to rapidly identify this organism. This project is trying to identify and characterize virulence related DNA sequences for use in rapid DNA based detection assays specific for E. sakazakii in powdered infant formula. Rapid detection of this pathogen in powdered infant formula will reduce infant illness by helping to keep contaminated products from the market.
Saxitoxins, the toxins responsible for paralytic shellfish poisoning (PSP), can cause illness and death in consumers of shellfish seafood. Monitoring for PSP is currently conducted by a mouse bioassay. The focus of this project is to produce conjugates of these saxitoxins with protein carriers to be use in developing field deployable immunoassays that are simple to run and reliable. Saxitoxin standards are also being developed for use in evaluating and validating the performance of these immunoassays. These standards and assays will enhance the FDA's effort to ensure the safety of shellfish seafood and protect consumers from PSP.
L. monocytogenes (LM) causes an important foodborne illness, human listeriosis. Much is unknown about how LM causes intestinal illness in susceptible populations. The intestinal illness phase of listeriosis is often the initial and only manifestation of this disease. This effort is using a variety of microbiological and molecular techniques to identify and characterize potential factors responsible for LM induced gastroenteritis. The information from this research should be useful in developing better detection methods for LM in foods and thus improve the safety of the food supply.
FDA needs a sensitive method for identifying E. sakazakii in infant formula. A gas chromatographic procedure using a flame ionization detector (GC-FID) and GC-mass spectrometry (GC-MS) is being developed to determine the cellular fatty acid profiles of various foodborne microbial pathogens. The bacteria will be processed to obtain whole cell fatty acid methyl esters (FAMEs) for GC analysis. A data set of fatty acid profiles for foodborne bacteria will be prepared. Analysis of FAMEs from E. sakazakii strains by this method can provide a sensitive confirmatory procedure for distinguishing E. sakazakii strains from closely related Enterobacter and Citrobacter species and will enhance efforts to ensure the safety of infant formula.
To help assure seafood safety and reduce economic fraud due to misbranding of seafood in the marketplace, the FDA maintains the Regulatory Fish Encyclopedia (RFE) and the Fish and Fisheries Products Hazards and Controls Guide. A major challenge to the identification of processed fish products is the inability to visually identify the fish after processing. We are validating a method for DNA bar-coding that uses DNA sequence differences to identify seafood species. We are generating a reference library of bar-code sequences for potentially hazardous and economically important fish species that should provide the FDA with a precise means of identifying seafood.
Bioluminex markets a test method that can potentially detect toxic contaminants by measuring the effects of chromatographically separated contaminants on the light emitting property of a bioluminescent bacterium. This is an inexpensive screening method that is portable and easy to do. This project is applying and evaluating this test method to the detection of toxic contaminants in foods. Successful results will help to track toxins and/or substances that can cause consumer illness. The successful evaluation of the Bioluminex technique may offer FDA a rapid method for detecting a variety of toxic chemicals in food.
Collaborations between FDA/CFSAN, the U of Washington, and the Institute of Photonics and Electronics in Prague have resulted in the development of a multi-channel Surface Plasmon Resonance (SPR) instrument that can detect a range of bacteria and toxins. We are now comparing these SPR based assays to other established methods, and optimizing the SPR sensing surface in an effort to develop simultaneous multi-analyte detection methods. We will then adapt these assays for use with food samples, and evaluate our data processing methods. These results should enhance our ability to rapidly and simultaneously detect pathogens and toxins in foods.
Illness caused by C. cayetanensis, C. hominis, and C. parvum has been associated with contaminated fresh produce and water sources. Pathogen detection using molecular-based approaches has replaced conventional microscopic techniques. PCR is an example of a sensitive molecular based approach that can quickly detect these pathogenic foodborne and waterborne microorganisms by providing faster diagnostic times plus enhanced sensitivity and specificity. Additional genetic studies of C. cayetanensis will increase our understanding of this parasitic pathogen and help develop improved detection methods for use in epidemiological studies and outbreak investigations.
Toxicology studies are a vital but expensive step in ensuring the public safety of consumer products. These safety studies are commonly conducted using large numbers of rodents. An alternative animal model is being explored that will improve these toxicity studies while reducing their time and cost. This effort will determine if the nematode (roundworm) C. elegans can be used as an alternative animal model in place of rodents for some toxicology safety studies.
Food-related chemicals are often evaluated for liver toxicity using animals. This effort is using cultured liver cells from humans and/or animals to assess the potential liver toxicity of food-related chemicals, to study cellular mechanisms that may explain known gender differences in liver toxicity, to study cellular mechanisms that may explain species differences in liver toxicity, and to study the role of inflammation as a co-contributor of chemical-induced liver toxicity. This information may help provide a more reliable extrapolation to humans of the hazards currently identified in laboratory animals and thus help reduce the risk of liver injury from food related chemicals.
Innovations in food processing have led to the creation of liquid products with higher levels of solids. The behavior of some foodborne pathogens such as Listeria monocytogenes (LM) in response to heat-treatment inactivation in these high solids level liquids is not known. This work is examining the heat resistance of LM in these products and should provide information for establishing an appropriate pasteurization processes for high solids milk products that will ensure their safety for the consumer.
Salmonella enteritidis (SE) is a leading cause of foodborne illness from consumption of raw eggs. DNA based real-time polymerase chain reaction (PCR) based assays have been used to detect SE in some foods. However, raw eggs contain compounds that interfere with PCR assays. Also, the present method of detecting this organism in eggs is too lengthy and not sufficiently sensitive. This effort is trying to combine a novel cell culture technique with real-time PCR to provide a faster and more sensitive detection alternative. It should improve our ability to evaluate and respond to potential SE outbreaks in eggs, and reduce foodborne illness from consuming SE contaminated raw eggs.
The human illness paralytic shellfish poisoning (PSP) is caused by the consumption of neurotoxin contaminated shellfish. These neurotoxins, collectively known as saxitoxins, are produced by certain algal species. The toxins can be transfer through the food chain via molluscan bivalves such as clams and oysters to humans. We are improving saxitoxin detection by evaluating the performance of a commercially available assays and extending the use of official analytical methods to clinical samples. We are also investigating analytical methods for identifying and quantifying toxins that do not use live animals or radioactive materials. This work will help improve toxin detection capabilities for regulatory and research purposes.
Checking foods for microbes, toxins, or allergens is often time consuming and labor intensive. This can limit the number of samples that can be rapidly tested. Interferometric based sensors have been used to detect bacteria, viruses, toxins, and chemical contaminants. We are evaluating a prototype portable waveguide interferometer developed by the Georgia Tech Research Institute to determine if it is suitable for automated detection of microbes, toxins, or allergens in foods. These efforts may lead to a fast, cheap, and reliable way to automatically check food for microbes and harmful ingredients at harvest and during processing.
Human foodborne illnesses associated with animals sources are common world-wide. There are several ways to control pathogens present in or on animals that may cause human illness. These measures include but are not limited to vaccines, antibiotics, and maintaining a hygienic environment. Despite such measures, the incidences of some food-borne illnesses are on the rise. This research is using animal and/or in vitro models to study susceptibility factors and immune responses to some food-borne pathogens. This study may provide useful information for managing human pathogens associated with animals and thus reduce foodborne illness in humans.
The incidence of food allergies has been increasing. Since there are no effective medical means of protecting allergic consumers, avoidance of the offending food is the only effective measure to prevent allergic reactions. In spite of new regulations mandating labeling that identifies allergenic ingredients, food allergens may still be unintentionally present. Detection methods for food allergens help to ensure label accuracy. Current detection methods usually test for a single food allergen. This effort is developing simultaneous testing methods for multiple food allergens to provide more convenient and cheaper allergen detection to help protect sensitive consumers.
During bacterial foodborne outbreaks, DNA typing methods often are used to determine if the bacterial pathogen from a patient matches that found in a suspected food. Salmonella Enteritidis (SE) is a bacterium very often associated with foodborne outbreaks from poultry. This research is obtaining additional DNA-sequence information about strains of SE to develop a more discriminating typing and comparison scheme for this pathogen. This will more definitively identify the strain of SE isolated from patients and food samples. This information should improve our understanding of poultry and SE associated foodborne outbreaks and reduce the incidence of human illness.
Shigella species are foodborne pathogens that pose a continual threat to food safety. An estimated 300,000 cases of shigellosis occur annually in the U.S. However, so far there is no fast identification method for Shigella available. Gas chromatographic and mass spectrometric test procedures will be used to determine the metabolic profiles of Shigella and other foodborne microbial pathogens. It is hoped that these metabolite profiles coupled with principal component analysis will be applicable to the quick detection and identification of the Shigella species. Quick detection of this foodborne pathogen can have a significant impact on public health.
This 12 month survey is examining the microbal content of raw shellstock oysters from retail stores across the US. The project is measuring seasonal and regional trends in the occurrence of total and pathogenic Vibrio parahaemolyticus (Vp). It will try to assess relationships between the presence of potential indicator organisms (bacterial and bacteriophage) and the occurrence human pathogens such as Vp. This project will help assess the effectiveness of the controls needed to avoid shellfish contamination and could lead to better guidance to the shellfish industry. The data may also be used to further refine the FDA Vp risk assessment.
Detecting chemical contamination in food, packaging, and cosmetics is often complex and time intensive. This can limit the number and types of samples tested, and response time in emergencies. Direct Analysis in Real Time (DART) ionization is an emerging sample preparation and introduction technology for chemical detectors with the potential to avoid time intensive and complex sample preparation. This project is trying to adapt the use of DART to reduce chemical testing times from hours to a few minutes. This technique should improve public health investigations into food and cosmetic that may have been chemically contaminated.
The current infection level of Salmonella Enteritidis (SE) in eggs is estimated to be 1 in 20,000. Approximately 65 billion eggs are produced in the US annually. Thus there are potentially millions of SE infected eggs produced every year. This project is examining the ability of microwave heating to produce a pasteurized in-the-shell egg quickly and with quality comparable to that of un-treated or non-pasteurized eggs. If successful, this in-the-shell egg pasteurization process should provide the consumer with an additional alternative that offers increased safety and protection from these SE infected eggs.
Raw milk may contain traditional foodborne pathogens but the true extent of the problem in not fully understood, especially in relation to current handling practices and the transport of milk to distant markets. This survey is providing more information on the level and type of pathogens that occur in raw milk and is helping to determine if other methods of pasteurization are necessary and effective. This study is also providing information that may be useful in adequately processing milk and milk products that have been intentionally contaminated with pathogenic bacteria, to enhance current food defense efforts.
Listeria monocytogenes causes rare but severe foodborne illness, which sometimes results in the deaths of susceptible individuals. These bacteria may contaminate foods through their ability to survive and become established in the environment of the food processing plant. Once established, they are very difficult to eradicate. This project will focus on identifying the genes and their characteristics that enable the bacteria to persist in the food plant environment. This information may be helpful in developing better cleaning and sanitizing procedures to prevent or control contamination of foods by this pathogen.
Salmonella remains a leading cause of foodborne illness despite efforts to prevent its contamination of foods. A better understanding is needed of how Salmonella is able to survive current prevention efforts. This project is seeking to identify Salmonella genes that allow it to persist in foods and food processing environments. This information may help in determining better ways to prevent or control Salmonella contamination of foods.
In 2004, because of methylmercury contamination, FDA and EPA provided seafood consumption advice for pregnant women, young children, and women who might become pregnant. FDA also conducted outreach to medical providers and WIC educators who often provide nutrition advice to pregnant women. FDA is now conducting a survey with these providers and educators to assess their awareness and understanding about seafood and methylmercury, and to determine the dietary advice they are offering to pregnant women. Based on the survey results, FDA can make decisions about the need for continued education and outreach for these medical providers and educators.
Heat processing procedures of food products are traditionally established by measuring thermal resistance of microorganisms in the food. Heat resistance of microorganisms is influenced by food composition such as sugar or acid concentrations. This study is examining thermal resistance of Yersinia species in different types of foods as related to their various food components. Thermal inactivation models will then be developed to help improve the food industry's understanding of the necessary thermal treatments required should contamination occur with this organism in an effort to better ensure product safety.
A polymerase chain reaction (PCR) method for enumerating foodborne Listeria monocytogenes (LM) has been developed but it takes 48 hours to complete. This project is trying to reduce the enumeration time to less than 24 hours and then to complete an in-house validation of the method with ready-to-eat (RTE) foods, with special attention on foods that allow the survival but not growth of LM under appropriate storage conditions. After multi-laboratory validation, the method may possibly permit a more relaxed but appropriately safe regulation of this class of RTE foods. This would allow resources to focus more on foods that do support growth of LM and represent a greater foodborne illness risk.
An estimated that 14% of all foodborne outbreaks reported in North America are attributed to the consumption of raw or minimally-processed fruits and vegetables. Recently, serious illnesses have been associated with consuming fresh tomatoes cultivated on the Eastern Shore of Virginia. Tomatoes were contaminated with a particular type of Salmonella called Newport. The association of Salmonella Newport with tomatoes is ecologically complex and not yet understood. This work is trying to uncover natural reservoirs for Newport that may be responsible for it infesting tomatoes and will attempt to prevent this infestation by using natural plant microbes present in the surrounding environment.
During the past decade many outbreaks of foodborne illness have been caused by pathogens carried on fresh leafy greens. A multi-institutional team is studying various steps involved in growing, harvesting, preparing, and packaging fresh leafy greens to better understand how these foods become contaminated. New ways to test the leafy greens for contamination by E. coli O157:H7 are being tried, and a study is being made of how product packaging may help improve product safety. This knowledge should be helpful in recommending improvements to industry practices to prevent contamination of fresh leafy greens and illnesses associated with contaminated product.
Clostridium botulinum spores are widely distributed in nature and are commonly found on raw foods that come in contact with soil. If low-acid foods carrying these spores are not properly processed, the surviving spores may grow and produce toxin. High pressure processing of foods appears to be able to destroy C. botulinum spores while maintaining a high quality food product. This research will help evaluate the use of high pressure processing as a means of producing safe low-acid food products.
Each year millions of foodborne illnesses caused by enteric viruses transmitted by food and water are reported in the United States. Detection and identification of the specific virus contaminants are essential for organizing responses to disease outbreaks, and for preventing the sale of contaminated products to help avoid future outbreaks. Current detection and identification techniques are run consecutively, not simultaneously, thereby reducing their timely application to perishable food items. This project uses multi-virus DNA microarrays to identify the virus strains responsible for an outbreak. The information should help to protect public health and reduce economic impact of these outbreaks.
Outbreaks of Salmonella infection have been caused by eating fresh tomatoes contaminated with this pathogen. There may be ways to prevent contamination by changing how tomatoes are handled after harvest. This project is studying the steps taken after harvesting tomatoes; for example, wash water temperature, volume of wash water, time of washing, and the presence of sanitizing chemicals. All of the steps taken together may be useful in eliminating Salmonella contamination on tomatoes, and this information may help to prevent foodborne illnesses from this source.
There is growing evidence that many people develop inflammatory conditions that contribute to a variety of adverse health effects. These inflammation episodes may be produced by environmental factors such as dietary pathogens. Vitamin D has been shown to have an important influence on the inflammatory response, but the dietary levels of Vitamin D that may help to protect the average American from some adverse effects of inflammation are unknown. This study is trying to determine how various levels of dietary Vitamin D may influence the effects of inflammation and help determine if current recommendations for dietary Vitamin D intake are appropriate.
It is thought that perfluorooctanesulfonate and perfluorooctanoic acid (PFOA) may possibly bioaccumulate because these chemicals have been shown to be found in human blood and have half-lives of 4-7 years. Some starting materials used to make these perfluorochemical grease proofing treatments for paper have been shown to degrade to PFOA. This project will evaluate the migration of perfluorochemical from food contact paper and improve our fundamental understanding of the analysis and migration of perfluorochemicals from food packaging. The information will help FDA to understand the occurrence of PFOA in food and help evaluate health risks.
In 2007, a pet food recall was initiated by several pet food manufacturers who had found their products had been contaminated with melamine and several related compounds. It was also determined that melamine had been fed to hogs and chickens intended for human consumption. Thus, humans may be exposed to melamine through consumption of contaminated meat and foods containing adulterated protein concentrate. Little is known about the stability of melamine in heat processed foods. This project will determine the fate of melamine during heat processing and will result in a method for measuring levels of melamine in heat processed foods. This method will help to identify heat processed foods that are adulterated with melamine.
This study examines the effect of acid food environments on the serological stability of staphylococcal enterotoxin and the denaturation/renaturation kinetics when toxin is exposed to acidic food environments. Changes in conformational structure of the toxin often prevents traditional antibody based serological identification. This project is trying to apply chemicals to reverse the conformational changes to staphylococcal enterotoxin structure so serological identification is successful. Rapid and accurate identification of this toxin in foods is important to protecting the consumer from eating contaminated foods.
Toxic proteins that are produced by plants and microbes are sometimes widely distributed in the environment and may contaminate the food supply either accidentally or intentionally. There is a shortage of methods that can reliably and easily detect these toxins in food. This project is trying to develop both rapid easy to use screening methods and confirmatory methods that can be used to monitor and test the food supply. These methods will detect toxins such as abrin, botulinium toxin and ricin in foods and help identify those foods that are safe for consumption. Confirmatory methods will be helpful in preserving the integrity of the food supply.
Intentional contamination using protein based toxins from plant and microbial sources have been identified as a possible threat to the food supply. There is a need for more validated rapid analytical methods to detect these toxins in food. This project is adapting a sensitive and specific method for detecting these toxins in biological fluids, to screen for their presence in foods. In addition, research on a rapid confirmatory test for these toxins based on time resolved fluorescence is being undertaken. This research is helping to provide rapid, easy to use and confirmatory methods to protect the integrity of the food supply.
Naturally occurring protein toxins such as botulinum toxin, which are available in purified form, are both a food safety and a food terrorism concern. Existing rapid screening tests for these toxins need to be followed by rapid, precise and accurate confirmatory tests. This project is evaluating advanced, multiplexed bioanalytical mass spectrometry methods that can specifically and rapidly detect botulinum toxin in foods. We are also developing multiplexed approaches for other toxins, including staphylococcal enterotoxins, ricin, and shiga toxins, to provide definitive identification and confirmation of toxin positive food samples obtained from rapid screening tests. These tests should help ensure food safety and security.
Animal models are widely used in studies designed to understand bacterial virulence and pathogenesis. Invertebrate animal models, such as the fruit fly Drosophila melanogester and the nematode (roundworm) Ceanorhabditis elegans have been developed as alternative virulence models because their genetic systems are well understood. C. elegans is being developed as a model to study virulence and host-defense mechanisms to foodborne bacterial pathogens and possible bio-threat agents.
Clostridium botulinum toxin is extremely potent and can cause paralysis and death. The bacteria and its toxin are associated with food commodities that are found in sealed, shelf-stable packaged cans, particularly when a mild heat treatment has killed other competing bacteria. Purified toxin may also be added to foods in an act of deliberate food contamination. The current standard method for detecting this toxin involves a mouse survival assay. This project is working on a rapid screening system to evaluate food samples with elevated toxin levels. In an intentional or accidental food contamination incident involving botulinum toxin, this method should help reduce the number of human illnesses.
One of the responsibilities of CFSAN is to develop better ways to identify bacteria that commonly cause foodborne illness in humans. CFSAN must now expand its efforts to include bacteria that are normally not found in food and typically do not cause foodborne illness, but which may be intentionally used to contaminate food. This project is developing new methods for detecting anthrax, tularemia, and plague bacteria in different kinds of foods. The results of this effort should further enhance the safety and integrity of the food supply and help protect consumers from intentional foodborne illness.
Molecular methods for distinguishing, identifying and tracking the bacteria involved in foodborne illness can be useful in analyzing incidences where food has been either naturally or intentionally contaminated. This project is using and further developing DNA based techniques to detect, identify and trace pathogenic strains of Escherichia coli, Shigella, and Salmonella. By providing additional information for identifying and tracking such bacterial pathogens, these techniques can help analyze the nature of foodborne outbreaks caused by these pathogens and thus help ensure the safety and integrity of the food supply.
Ricin is a potent protein toxin found in the seeds of the castor bean plant. Ricin has the potential to be used as an intentional food poison. Information is limited on the heat and chemical stability of ricin. This project is evaluating the conditions required to inactivate ricin with heat or chemicals to help ensure the safety and integrity of the food supply, and to understand what possible effects chemical treatments may have on the detection or toxicity of ricin in food.
Bacillus anthracis is a bacterial pathogen that causes anthrax in animals and sometimes humans. The kind of illness varies depending upon the route of exposure to the pathogen, such as whether the organism is inhaled or penetrates the skin. Anthrax ingestion in humans causes gastrointestinal illness. Spores of this pathogen are more resistant to some methods used for food processing or preparation, such as heating and drying. This study is seeking a better understanding of this pathogen's survival properties in different foods as a means for developing improved preventive measures that will reduce illness from this pathogen and enhance the safety of our food supply.
Botulinum Neurotoxin (BoNT) can be deadly to persons who consume contaminated product and don't receive proper medical treatment. Yet the toxin is very sensitive to heat. It is unknown if the thermal sensitivity of BoNT changes in different liquid foods. This project is using differential scanning calorimetry (DSC) to see if such relative thermal stability effects exist, and if DSC can directly measure toxin strength in suspension. If this approach works it can help determine how well existing thermal processes reduce or eliminate BoNT and help ensure safer production of a variety of liquid foods. Also, direct DSC toxin strength measurement would provide a faster and easier measurement alternative to the traditional BoNT mouse bioassay.
A major contamination incident in Japan involved yogurt products that had used contaminated milk ingredients. That incident demonstrated that certain toxins can survive two cycles of pasteurization and a low pH environment. The ability to maintain the wholesomeness of food products is critical and highly dependent upon the methods used to check the product. This project is developing a confirmatory test procedure for retesting presumptive negative or non-contaminated samples. The results from this project may serve to increase the accuracy of existing approaches that test for contaminants in the food supply.
