Since the spring and early summer of 1996, major outbreaks in North America attributed to Cyclospora cayetanensis have been epidemiologically-linked to the consumption of spring crop raspberries from Guatemala. Smaller outbreaks of cyclosporiasis in the United States during the 1990s have been associated with the consumption of other fresh produce-mesclun lettuce and basil. Unpasturized apple cider has been a source for Cryptosporidum parvum infections; scallions have also been implicated. Contaminated water sources are also suspected as a major route in the transmission of all three parasitic protozoa.

The difficulties in assessing and controlling possible foodborne contamination and infections with these coccidia are many. There is a general lack of knowledge concerning life cycles (Cyclospora cayetanensis, Microsporidia spp), animal vectors and/or reservoirs, biochemistry,and the inability to efficiently culture the parasite either in an animal model (Cyclospora cayetanensis) or a tissue culture-based system (Cyclospora cayetanensis and Cryptosporidium parvum). An inadequate supply of Cyclospora cayetanensis also contributes to our general lack of understanding.

Neither a means for assessing their pathogenicity and survival after exposure to potential intervention treatments nor sufficient infectious dose information is available. Current methods to detect foodborne contamination lack the necessary sensitivity and reliability.

In this 3-yr plan, improved sampling and detection methods will be pursued to include fast, reliable, and highly sensitive PCR methodologies that can be applied to a variety of food and water sources. The development of systems for evaluating intervention strategies will include in vitro cultivation of oocysts and identification of model hosts. Development of animal models that mimic human illness caused by these protozoa will be attempted and dose-response studies in normal and immunocompromised animals will then be conducted to provide data for developing risk assessment models. Alternate protozoa such as Eimeria spp. will also be evaluated as research models in the absence of adequate supplies of Cyclospora cayetanensis.

The results of this project will provide for an improved ability to detect and reduce the risk of food and water-borne illness attributed to parasitic protozoa.

Currently, there is no practical test to determine if seafood products contain hazardous strains of v. vulnificus. We propose to solve this problem by defining DNA sequences specific to virulent strains, and then developing simple DNA probe test(s) that can be used by industry and public health organizations to assess risk. We will use two techniques to identify segments of DNA that are unique to virulent strains, 1) by "subtracting" DNA of non-virulent strains from virulent strains, thereby identifying virulent-specific DNA sequences, and 2) by allowing the mouse model to directly select for strains that have acquired DNA sequences from virulent V. vulnificus strains that are randomly cloned into non-virulent strains.

1. Develop a household-level HACCP-like model for home prepared chicken and salad using objective measurements such as direct observations and microbiological indicators.
2. Test validity of food safety self-reported behaviors against direct home observations and microbiological outcomes.
3. Develop and pre-test a Puerto Rican chicken and salad HACCPized recipe that incorporates kitchen sanitation principles.

Findings will be used to develop and pre-test with 10 subjects a chicken and salad HACCPized recipe that incorporates kitchen sanitation principles. Thus, project has major implications for effective delivery of Cooperative Extension System-based food safety education for low-income audiences.

One barrier for developing cost-effective food safety education targeting low-income consumers is the lack of objective and valid assessments of food safety risks at home. The aims of this study are to: A) Develop a household-level HACCP-like model for home prepared chicken and salad using objective measurements such as direct observations and microbiological indicators. B) Test validity of food safety self-reported behaviors against direct home observations and microbiological outcomes. C) Develop and pre-test a Puerto Rican chicken and salad HACCPized recipe that incorporates kitchen sanitation principles.

Illness caused by foodborne pathogens remains an important cause of illness and death in the United States, with significant economic costs. In order to prioritize how available funds should be spent, it is critical that we know where the problems are: i.e., that we know which combinations of pathogenic microorganism and food have the greatest impact on public health. This is not an easy task: the food production system is complex, and major problems have been encountered in trying to create the models and databases needed to address this question. The Food Safety Research Consortium (FSRC), a group of seven leading universities and institutes, was established to conduct and encourage multi-disciplinary research to build an integrated "system" understanding of foodborne illness and decision tools for prioritizing risk reduction opportunities. As part of this process, the FSRC has developed a prototype mathematical model for ranking the public health impact of specific pathogen-food combinations. The current proposal will allow further development of the FSRC prototype mathematical model for ranking the public health impact of specific pathogen-food combinations. This will include incorporation of additional economic parameters; the inclusion of estimates of uncertainty; further work on a shorthand risk-based food attribution method; facilitation of consensus development for food categories; and establishment of a web-based interface for the model.

The expected outcome is a scientifically valid, computer-based risk ranking model that will be readily accessible to decision makers in government and industry, and that will have utility in policy analysis and priority setting, research, education, and extension activities. While the FSRC has make significant progress in this direction with its current Foodborne Illness Risk Ranking Model, it remains a prototype model with clear weaknesses that limit its utility; and, without a good web interface, its accessibility is also limited. Design elements of the model will be presented for discussion and critique at workshops (early spring 2005 on posthoc evaluation of food safety interventions) and the final national conference (June or September 2005) currently planned by Iowa State University/FSRC as part of the CSREES-funded project "Prioritizing Opportunities to Reduce Foodborne Disease." We anticipate that this material, as it is finalized, will also be submitted for publication in peer-reviewed journals. Once a web interface is in place, we will also be monitoring "hits" on the model web site: utility of the model can be gauged, at least in part, by the number of persons accessing the model.

1. Determine the variation between strains of a pathogen,
2. Create models for the lag phase duration when environmental conditions change,
3. Model growth and survival in modified atmosphere packaged foods, and
4. Incorporate microbial models into a new version of the Pathogen Modeling Program (PMP) which can model a processing operation and conduct risk assessments.

1. To evaluate existing dose-response models for microbial risk assessment.
2. To develop improved models for estimating probabilities of infection and disease.
3. To develop methods for incorporating model uncertainty into microbial risk assessment.

1. One paper on a new approach to incorporating model uncertainties for risk assessment was accepted for publication.
2. One paper on statistical models for microbial risk assessment has been submitted for publication.
3. An invited paper was presented at the Eastern North American Region (ENAR) of the International Biometric Society.
4. An invited talk was presented at the Toxicology and Risk Assessment Approaches for the 21st Century.
5. Recruited ORISE post doc.

FY 2001 Plans:

1. Continue research on dose-response modeling of microbial risk assessment.
2. Evaluate the approach to incorporating model uncertainties in risk estimation.