Survival of enteric pathogens on the surface of fresh produce and intake of heterotrophic bacteria in the United States

Persistent Link:
http://hdl.handle.net/10150/280656
Title:
Survival of enteric pathogens on the surface of fresh produce and intake of heterotrophic bacteria in the United States
Author:
Stine, William S.
Issue Date:
2004
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Disease due to the consumption of food contaminated with enteric microorganisms has been well established. The first study described in this dissertation was designed to determine the effect of relative humidity on the pre-harvest survival of enteric pathogens on the surfaces of fresh produce. Additionally, Clostridium perfringens was evaluated as an indicator of fecal contamination on fresh produce. Pathogenic and surrogate microorganisms, including Escherichia coli O157:H7, Escherichia coli ATCC 25922, Salmonella enterica subsp. enterica, Shigella sonnei, C. perfringens, coliphage PRD1, feline calicivirus (FCV), and hepatitis A virus (HAV), were inoculated onto the surfaces of cantaloupe, iceberg lettuce, and bell peppers. Experiments were conducted in a controlled environment chamber. Survival of microorganisms on the produce surfaces was not uniformly affected by relative humidity. However, due to the survival of all microorganisms at least 14 days in at least one experiment, measures should be taken to lessen the exposure of produce to fecal contamination as harvest time approaches. C. perfringens survived longer than all other bacteria and feline calicivirus in all experiments, with the exception of E. coli O157:H7 and S. enterica subsp. enterica on lettuce. This trend suggests that C. perfringens may be an acceptable indicator of bacterial contamination and survival in various environments and on different types of crops. The second study was conducted to determine the intake of heterotrophic bacteria by the average person in the United States from food and water. A literature review was conducted to determine the concentration of heterotrophic plate count (HPC) bacteria in foods and water from the household tap. Food items from grocery stores and fast food restaurants in Tucson, AZ were also evaluated for HPC bacteria. It was determined that in the United States, 0.048 to 4.5% of the typical consumer's HPC bacteria intake is derived from water consumed from the household tap. Therefore, HPC bacteria in tap water do not represent a significant source of the total HPC bacteria consumed in the average diet of individuals in the United States.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Agriculture, Food Science and Technology.; Biology, Microbiology.; Environmental Sciences.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Soil, Water and Environmental Science
Degree Grantor:
University of Arizona
Advisor:
Gerba, Charles P.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleSurvival of enteric pathogens on the surface of fresh produce and intake of heterotrophic bacteria in the United Statesen_US
dc.creatorStine, William S.en_US
dc.contributor.authorStine, William S.en_US
dc.date.issued2004en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractDisease due to the consumption of food contaminated with enteric microorganisms has been well established. The first study described in this dissertation was designed to determine the effect of relative humidity on the pre-harvest survival of enteric pathogens on the surfaces of fresh produce. Additionally, Clostridium perfringens was evaluated as an indicator of fecal contamination on fresh produce. Pathogenic and surrogate microorganisms, including Escherichia coli O157:H7, Escherichia coli ATCC 25922, Salmonella enterica subsp. enterica, Shigella sonnei, C. perfringens, coliphage PRD1, feline calicivirus (FCV), and hepatitis A virus (HAV), were inoculated onto the surfaces of cantaloupe, iceberg lettuce, and bell peppers. Experiments were conducted in a controlled environment chamber. Survival of microorganisms on the produce surfaces was not uniformly affected by relative humidity. However, due to the survival of all microorganisms at least 14 days in at least one experiment, measures should be taken to lessen the exposure of produce to fecal contamination as harvest time approaches. C. perfringens survived longer than all other bacteria and feline calicivirus in all experiments, with the exception of E. coli O157:H7 and S. enterica subsp. enterica on lettuce. This trend suggests that C. perfringens may be an acceptable indicator of bacterial contamination and survival in various environments and on different types of crops. The second study was conducted to determine the intake of heterotrophic bacteria by the average person in the United States from food and water. A literature review was conducted to determine the concentration of heterotrophic plate count (HPC) bacteria in foods and water from the household tap. Food items from grocery stores and fast food restaurants in Tucson, AZ were also evaluated for HPC bacteria. It was determined that in the United States, 0.048 to 4.5% of the typical consumer's HPC bacteria intake is derived from water consumed from the household tap. Therefore, HPC bacteria in tap water do not represent a significant source of the total HPC bacteria consumed in the average diet of individuals in the United States.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectAgriculture, Food Science and Technology.en_US
dc.subjectBiology, Microbiology.en_US
dc.subjectEnvironmental Sciences.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineSoil, Water and Environmental Scienceen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorGerba, Charles P.en_US
dc.identifier.proquest3145134en_US
dc.identifier.bibrecord.b47213619en_US
All Items in UA Campus Repository are protected by copyright, with all rights reserved, unless otherwise indicated.