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Effects of Environmental Conditions, Phytochemicals, Modified Atmosphere Packaging and other Parameters for the Growth and Survival of Foodborne Pathogens on Produce, Particularly Sprouted Seeds

Investigators
Whiting, Richard
Institutions
DHHS/FDA - Center for Food Safety & Applied Nutrition
Start date
1999
End date
2002
Objective
This project focuses on evaluating the effects of environmental and food formulations factors on pathogen growth in minimally processed foods and to manipulate these factors to reduce or eliminate pathogen growth.
More information

Processing of commercial produce is a rapidly expanding industry that offers convenient products with fresh-like qualities. Preservation and extension of shelf life for produce is frequently achieved through refrigeration, bactericidal rinses, modified atmosphere packaging and other technologies.

To assure the safety of minimally processed produce, it is essential to obtain detailed information on the effect of environmental and food formulation factors on the growth and survival of pathogenic bacteria that may be present.

For instance, various plants contain phytochemicals that are capable of suppressing microbial growth. The resident microflora on produce, which can vary with product, can affect or alter the relative growth rates of pathogens on produce. In addition, the growth of pathogenic bacteria during germination of sprouted seeds may greatly increase the risk of foodborne diseases.

These studies will evaluate the effects of phytochemicals, environmental conditions, modified atmospheres, microflora composition and other factors on the growth and survival of Listeria monocytogenes, Escherichia coli O157:H7, Salmonella spp., and Bacillus cereus, as well as appropriate surrogate microorganisms, on assorted fruits and vegetables. Also, sprouted seeds will be a target for investigating natural contamination by pathogens.

This project will generate data on the presence of Staphylococcus aureus and Bacillus cereus on domestic sprouted seeds. Simulation studies of environmental conditions, including modified atmosphere packaging, will determine whether they can prevent or delay the growth of these pathogens. Enumeration of Listeria monocytogenes on produce is difficult and has been one reason there is limited data on contamination rates and levels. An improved colony counting method that is rapid, easy to conduct and unaffected by the normal microflora will make surveys for L. monocytogenes contamination more feasible. Growth and survival of L. monocytogenes will be modeled to provide information for designing process systems and for risk assessments. E. coli O157:H7 can also contaminate produce and grow. Models will be developed that can predict the likely growth at different temperatures and under modified atmospheres.

These data will serve as a basis for developing guidelines for produce handling and intervention technologies.

Funding Source
Center For Food Safety and Applied Nutrition
Project number
FSI-03-RSVP-38120
Categories
Bacterial Pathogens