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  1. Environmental Studies

California Longitudinal Study (2020 – present)

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FDA, in collaboration with the California Department of Food and Agriculture, the University of California, Davis’ Western Center for Food Safety, and agricultural stakeholders in the Central Coast of California, is conducting a multi-year study in the Central Coast agricultural region to identify environmental factors that significantly contribute to the introduction, persistence, growth, and spread of foodborne pathogens that could contaminate produce during production and harvest. We are also interested in identifying factors that lead to pathogen die-off.

The Central Coast of California is farmed year-round and supplies a large portion of the nation’s leafy greens. It also produces artichokes, broccoli, cauliflower, celery, strawberries, tomatoes, wine grapes, and other crops. It is precisely because the region, sometimes called the “salad bowl of the world,” grows so much produce, that researchers are interested in studying it. There have been periodic foodborne illness outbreaks associated with produce grown in California, including three outbreaks in the Fall of 2019 tied to leafy greens from the Central Coast, so increasing our understanding of the ecology of this growing region as it pertains to foodborne pathogen persistence is of great benefit to growers, cooperative extension specialists, and food safety officials.

This study involves collecting environmental samples from the Central Coast of California’s agricultural region throughout the year. Samples will be collected from agricultural water, surface water, sediment, soil and soil components including compost and dust, animal fecal material, and other sources.  Attention will also be given to the geography, topography, and meteorological conditions of the study region and the types and locations of agricultural and other land use activities relative to produce production areas. Samples will be analyzed using molecular diagnostic and microbial culture methods, metagenomics, and whole genome sequencing to identify pathogens and microbiological organisms that can be indicators of unhygienic conditions. Through repeated sample collection, testing, measurement, and observation, we hope to gain insight into fluctuations in the types and prevalence of pathogens and indicator organisms over time, including variability across different seasons. Complementing the environmental surveillance, laboratory studies will explore how the pathogens collected from the study area adapt to different growing conditions and interact with host produce plants, which also may lead to new approaches for limiting or eliminating pathogens in growing areas.

The findings of this study will contribute to a better understanding of the impact various environmental factors can have on food safety. This information, in combination with the findings from studies like it, can be used to refine best practices for growers, so they may continually improve the safety of their products.

Study Related Announcements

Study Collaborators

  • FDA
  • California Department of Food and Agriculture
  • University of California, Davis, Western Center for Food Safety
  • Local members of the produce, viticulture, cattle, and compost industries
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