Progress 02/01/10 to 01/31/14
Outputs
Target Audience: The food system is worldwide. However, the US agricultural, fresh produce, and food industries are our primary arget audiences for this research. Minimizing food pathogens is a primary effort of these industries to maintain a safe food supply and to enhance human health. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? This project resulted in the training a PhD student, a postdoctoral scientist, and 4 undergraduate students in food safety research. How have the results been disseminated to communities of interest? Research results were presented as a keynote speaker at the Puerto Rico ASM Microbiology Symposium (2013) and no less than 4 other presentations at international conferences during the duration of the project. This project has also included consultations with local food processors and members of the FDA. Dissemination of knowledge beyond the scientific audience occured through multiple venues, through on site tours of the research laboratory and a research program overview to members of the public that visit the university. On site tours were delivered to university students, international visitors, casual visitors to the university (members of the public) and stakeholders (representing industrial sectors related to food science). What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
This project resulted in the identification of abiotic environmental conditions, specifically moisture and temperature, and composition of the phyllosphere microbiota (biotic conditions) which influence the survival of virulent and avirulent (attenuated) E. coli O157:H7 strains on Romaine lettuce plants. We established a laboratory system to measure the growth and survival of virulent and attenuated E. coli O157:H7 isolates in the growth chamber on lettuce exposed to environmental regimes that mimic those found in the field. We showed that E coli O157:H7 dies on plant leaves in an agricultural field rather than survives in a dormant state. We found that field lettuce contains a dynamic microbiota that can fluctuate on a day-to-day basis. Inoculation of E. coli into the phyllosphere alters the composition (amounts) of the other bacteria present. The PhD student in this project won numerous awards for his research including a prize for the best poster at the Robert Mondavi Institute on 2 separate years and the Chancellor's award for the best talk at the UC Davis Interdisciplinary Research Symposium in 2013.
Publications
- Type:
Journal Articles
Status:
Accepted
Year Published:
2013
Citation:
Thomas Williams, Anne-laure Moyne, Linda J. Harris, and Maria L. Marco. 2013. Season, irrigation, leaf age, and Escherichia coli inoculation influence the bacterial diversity in the lettuce phyllosphere. PlosOne. e68642
- Type:
Journal Articles
Status:
Accepted
Year Published:
2013
Citation:
Anne-laure Moyne, Linda J. Harris, and Maria L. Marco. 2013. Assessments of total and viable Escherichia coli O157:H7 on field and laboratory grown lettuce. PlosOne. e70643.
|
Progress 02/01/12 to 01/31/13
Outputs
OUTPUTS: Activities in this project address the need to reduce the risk of food-borne illness due to the consumption of leafy green produce. Fresh fruits and vegetables have been increasingly implicated in outbreaks of food-borne illness, and in particular, outbreaks of enterohemorrhagic Escherichia coli O157:H7 have been associated with consumption of leafy green vegetables. Lettuce is the main item within this group responsible for produce-associated outbreaks and pathogen contamination of the lettuce plants likely occurs in the field prior to harvest. During the review period, major outputs include the application of culture and molecular methods to quantify the survival of different (a)virulent strains of E coli O157:H7 cells on lettuce maintained under field-relevant environmental conditions. This project also resulted in novel comparisons between E coli O157:H7 survival and the indigenous leaf surface microbiota in the field and growth chamber that can be used to prevent or predict pathogen survival. Events included conference attendance at the annual meeting of the International Society for Microbial Ecology meeting in Copenhagen, Denmark. A well-attended presentation on the project was given at this meeting by the graduate student, Tom Williams, in a session on plant-microbe interactions. This project has also included consultations with local food processors and members of the FDA. This project provided ongoing training of a PhD student and a postdoctoral scientist. Products include knowledge of E coli O157:H7 viability states on fresh produce and significant correlations between the amounts and types of phyllosphere microoorganisms and EcO157:H7 survival on lettuce plants. Dissemination of knowledge beyond the scientific audience occurs through multiple venues, through on site tours of the research laboratory and a research program overview to members of the public that visit the university. On site tours have been delivered to university students, international visitors, casual visitors to the university (members of the public) and stakeholders (representing industrial sectors related to food science). PARTICIPANTS: Maria L Marco, Ph.D. - Assistant Professor and Food Microbiologist, AES - Principal Investigator who oversees the work and is responsible for the design and execution of the project. Thomas Williams a PhD student, receiving training from Dr. Marco on phyllosphere microbiology and microbial food safety. Responsible for conducting and analyzing results from experiments designed in cooperation with Dr. Marco. Anne Laure Moyne - Project Scientist - Receiving training from Dr. Marco and Dr. Linda Harris on methods for identification of viable E coli O157:H7 on lettuce and for identification of environmental conditions that influence pathogen survival on plants. Linda Harris Ph.D. - Specialist In Cooperative Extension University of California, Davis, provided training for performing analysis of food borne pathogens on plants. Anne Jaffe - high school student in the Young Scholars Program (YSP) at The University of California, Davis, gained basic training in microbiology and molecular biology. Partnered with Department of Food Science and Technology and College of Agriculture and Environmental Sciences colleagues to communicate information to California citizens during through "campus visits" and email communications. The need for food safety to ensure healthy food for California and US citizens demands that we educate domestic and international producers. TARGET AUDIENCES: The food system is worldwide. However, the US agricultural, fresh produce, and food industries remain primary our target audiences for this research. Minimizing food pathogens is a primary effort of these industries to maintain a safe food supply and to enhance human health. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
This project is focused on understanding the factors affecting E. coli O157:H7 survival on lettuce that can be applied to the development of improved control measures aimed at mitigating the risk of the organism surviving after a contamination event. E. coli serotype O157:H7 is a significant foodborne pathogen, owing to its low infectious dose, severity of infection, and high association with leafy green outbreaks. Preharvest contamination of the plants in the field is considered the main point of entry of the pathogen. Although E. coli O157:H7 is not a good colonist of plants, it is able to survive and, under some conditions, grow on lettuce leaf surfaces. The phyllosphere or aerial-portion of plants, is generally regarded as a harsh environment for microorganisms containing both abiotic and biotic (microbial) stresses. The objectives driving this project have resulted in the identification of abiotic environmental conditions, specifically moisture and temperature, and composition of the phyllosphere microbiota (biotic conditions) which potentially influence the survival of virulent and avirulent (attenuated) E. coli O157:H7 strains on Romaine lettuce plants. We established a laboratory system to measure the growth and survival of virulent and attenuated E. coli O157:H7 isolates in the growth chamber on lettuce exposed to environmental regimes that mimic those found in the field. This system impacts study of food borne-pathogens on plants because it offers opportunities to simulate environmental conditions found in the field. Quantification of E. coli using culture-dependent methods in this project is applicable for use by the fresh produce industry and other food companies. The bacterial inhabitants of the phyllosphere, identified by high-throughput DNA profiling analyses, show the biological potential of plants as carriers of bacteria with beneficial impacts on human health. In particular, specific bacterial isolates from the lettuce possess the ability to inhibit E coli growth and hence indicate the ability of the native plant microbiota to modulate pathogen survival. Ultimately, identification of the factors influencing the survival of E. coli O157:H7 on lettuce is expected to inform the development of agricultural practices that reduce outbreaks associated with these economically valuable and otherwise healthy crops.
Publications
- Invited talk: Lettuce phyllosphere microbiota: seasonal diversity and impact on microbial food safety International Society for Microbial Ecology Copenhagen, Denmark, August 19, 2012.
|
Progress 02/01/11 to 01/31/12
Outputs
OUTPUTS: Activities in this project address the need to reduce the risk of food-borne illness due to the consumption of leafy green produce. Fresh fruits and vegetables have been increasingly implicated in outbreaks of food-borne illness, and in particular, outbreaks of enterohemorrhagic Escherichia coli O157:H7 have been associated with consumption of leafy green vegetables. Lettuce is the main item within this group responsible for produce-associated outbreaks and pathogen contamination of the lettuce plants likely occurs in the field prior to harvest. During the review period, major outputs include the application of culture independent methods for quantifying total and viable E coli O157:H7 cells on field-grown lettuce an in the growth chamber on plants maintained under field-relevant environmental regimes. This project also resulted in the identification of the other bacteria colonizing field-grown lettuce exposed to E coli O157:H7 and irrigated either by spray or surface drip. Events included conference attendance at the annual meeting of the American Phytopathology Society, Honolulu, HI. A presentation was given at this meeting in a special session entitled "Omics approaches to the characterization of interactions between human enteric pathogens and plants: a plant pathologists perspective". The PI also attended the USDA program director's meeting in Milwaukee, Wisconsin. This project has also included consulting with local food processors and members of the FDA. This project provided ongoing training of a PhD student and a postdoctoral scientist. Products include knowledge of E coli O157:H7 viability states on produce and seasonal and irrigation effects on the native lettuce phyllosphere microbiota which might influence EcO157:H7 persistence. Dissemination of knowledge beyond the scientific audience occurs through multiple venues, through on site tours of the research laboratory and a research program overview to members of the public that visit the university. On site tours have been delivered to university students, international visitors, casual visitors to the university (members of the public) and stakeholders (representing industrial sectors related to food science). PARTICIPANTS: Maria L Marco, Ph.D. - Assistant Professor and Food Microbiologist, AES - Principal Investigator. Responsible for the design and execution of the project. Thomas Williams, Graduate Student - Receiving training from Dr. Marco on phyllosphere microbiology. Responsible for conducting and analyzing results from experiments designed in cooperation with Dr. Marco. Anne Laure Moyne - Project Scientist - Receiving training from Dr. Marco and Dr. Linda Harris on methods for identification of viable E coli O157:H7 on plants and determination of environmental conditions on pathogen survival on plants. Linda Harris Ph.D. - Specialist In Cooperative Extension University of California, Davis, provided training for performing analysis of food borne pathogens on plants. Ashley Ngu - high school student in the Young Scholars Program (YSP) at The University of California, Davis, gained basic training in microbiology and molecular biology. Partnered with Department of Food Science and Technology and College of Agriculture and Environmental Sciences colleagues to communicate information to California citizens during through "campus visits" and email communications. The need for food safety to ensure healthy food for California and US citizens demands that we educate domestic and international producers. TARGET AUDIENCES: The food system is worldwide. However, the US agricultural, fresh produce, and food industries remain primary our target audiences for this research. Minimizing food pathogens is a primary effort of these industries to maintain a safe food supply and to enhance human health. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
This project is focused on understanding the factors affecting E. coli O157:H7 survival on lettuce which can be applied to the development of improved control measures aimed at mitigating the risk of the organism surviving after a contamination event. E. coli serotype O157:H7 is a significant foodborne pathogen, owing to its low infectious dose, severity of infection, and high association with leafy green outbreaks. Preharvest contamination of the plants in the field is considered the main point of entry of the pathogen. Although E. coli O157:H7 is not considered to be a good colonist of plants, it is able to survive and, under some conditions, grow on lettuce leaf surfaces. The phyllosphere or aerial-portion of plants, is generally regarded as a harsh environment for microorganisms containing both abiotic and biotic (microbial) stresses. The objectives driving this project have resulted in the identification of abiotic environmental conditions, specifically moisture and temperature, and composition of the phyllosphere microbiota (biotic conditions) which potentially influence the survival of virulent and avirulent (attenuated) E. coli O157:H7 strains on Romaine lettuce plants. We established a laboratory system to measure the growth and survival of virulent and attenuated E. coli O157:H7 isolates in the growth chamber on lettuce exposed to environmental regimes that mimic those found in the field. This system impacts study of food borne-pathogens on plants because it offers opportunities to simulate environmental conditions found in the field. Quantification of E. coli using culture-dependent methods in this project is applicable for use by the fresh produce industry and other food companies. The bacterial inhabitants of the phyllosphere, identified by high-throughput DNA profiling analyses, show the biological potential of plants as carriers of bacteria with beneficial impacts on human health. In particular, specific bacterial isolates from the lettuce possess the ability to inhibit E coli growth and hence indicate the ability of the native plant microbiota to modulate pathogen survival. Ultimately, identification of the factors influencing the survival of E. coli O157:H7 on lettuce is expected to inform development of agricultural practices that may reduce outbreaks associated with these economically valuable and otherwise healthy crops.
Publications
- No publications reported this period
|
Progress 02/01/10 to 01/31/11
Outputs
OUTPUTS: Activities in this project address the need to reduce the risk of food-borne illness due to the consumption of leafy green produce. Fresh fruits and vegetables have been increasingly implicated in outbreaks of food-borne illness, and in particular, outbreaks of enterohemorrhagic Escherichia coli O157:H7 have been associated with consumption of leafy green vegetables. Lettuce is the main item within this group responsible for produce-associated outbreaks and pathogen contamination of the lettuce plants likely occurs in the field prior to harvest. During the review period, major outputs include the development of culture independent methods for quantifying total and viable E coli O157:H7 cells on field-grown lettuce and the identification of the other bacteria colonizing lettuce plant surfaces. Events include conference attendance at the 9th International Symposium on the Microbiology of Aerial Plant Surfaces in Corvallis, Oregon, the International Food Technologists meeting in Chicago, Illinois, and the Center for Produce Safety annual symposium. This project has also included consulting with local food processors and members of the FDA. This project provided ongoing training of a PhD student and a postdoctoral scientist. Products include the development methods for culture-independent quantification of E coli O157:H7 on produce and methods for identification of phyllospere microbiota. Dissemination of knowledge beyond the scientific audience occurs through multiple venues, through on site tours of the research laboratory and a research program overview to members of the public that visit the university. On site tours have been delivered to university students, international visitors, casual visitors to the university (members of the public) and stakeholders (representing industrial sectors related to food science). PARTICIPANTS: Maria L Marco, Ph.D. - Assistant Professor and Food Microbiologist, AES -Principal Investigator. Responsible for the design and execution of the project. Thomas Williams, Graduate Student - Receiving training from Dr. Marco on phyllosphere microbiology. Responsible for conducting and analyzing results from experiments designed in cooperation with Dr. Marco. Anne Laure Moyne - Project Scientist - Receiving training from Dr. Marco and Dr. Linda Harris on methods for identification of viable E coli O157:H7 on plants and determination of environmental conditions on pathogen survival on plants. Linda Harris Ph.D. - Specialist In Cooperative Extension University of California, Davis, provided training for performing analysis of food borne pathogens on plants. Partnered with Department of Food Science and Technology and College of Agriculture and Environmental Sciences colleagues to communicate information to California citizens during through campus visits and email communications. The need for food safety to ensure healthy food for California and US citizens demands that we educate domestic and international producers. TARGET AUDIENCES: The food system is worldwide. However, the US agricultural, fresh produce, and food industries remain primary our target audiences for this research. Minimizing food pathogens is a primary effort of these industries to maintain a safe food supply and to enhance human health. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
This project is focused on understanding the factors affecting E. coli O157:H7 survival on lettuce which can be applied to the development of improved control measures aimed at mitigating the risk of the organism surviving after a contamination event. E. coli serotype O157:H7 is a significant foodborne pathogen, owing to its low infectious dose, severity of infection, and high association with leafy green outbreaks. Preharvest contamination of the plants in the field is considered the main point of entry of the pathogen. Although E. coli O157:H7 is not considered to be a good colonist of plants, it is able to survive and, under some conditions, grow on lettuce leaf surfaces. The phyllosphere or aerial-portion of plants, is generally regarded as a harsh environment for microorganisms containing both abiotic and biotic (microbial) stresses. The objectives driving this project have resulted in the identification of abiotic environmental conditions, specifically moisture and temperature, and composition of the phyllosphere microbiota (biotic conditions) which potentially influence the survival of virulent and avirulent (attenuated) E. coli O157:H7 strains on Romaine lettuce plants. We established a laboratory system to measure the growth and survival of virulent and attenuated E. coli O157:H7 isolates in the growth chamber on lettuce exposed to environmental regimes that mimic those found in the field. This system impacts study of food borne-pathogens on plants because it offers opportunities to simulate environmental conditions found in the field. Quantification of E. coli using culture-dependent methods in this project is applicable for use by the fresh produce industry and other food companies. The bacterial inhabitants of the phyllosphere, identified by high-throughput DNA profiling analyses, show the biological potential of plants as carriers of bacteria with beneficial impacts on human health. In particular, specific bacterial isolates from the lettuce possess the ability to inhibit E coli growth and hence indicate the ability of the native plant microbiota to modulate pathogen survival. Ultimately, identification of the factors influencing the survival of E. coli O157:H7 on lettuce is expected to inform development of agricultural practices that may reduce outbreaks associated with these economically valuable and otherwise healthy crops.
Publications
- No publications reported this period
|
|