Progress 01/01/16 to 05/15/19
Outputs
Target Audience:This project had two components. One centered on agricultural production at research stations and in a BSL3 greenhouse and the other focusing on outreach and extension to farmers covered under the produce safety rule (PSR). Topics covered were specific to alternative farming practices used to control pathogens in soil and improve soil health. Specific to the outreach components our target audience was farmers in NC that grow cover produced subject to the PSR. During produce safety (PSA) training events, grower association meetings, field days and on-farm visits we surveyed the agricultural practices used by these farmers, their knowledge about food safety and pathogen contamination in the field or packinghouse and whether they were aware of bioremediation techniques that could be used to reduce or eliminate the presence of enteric pathogens in soil. Our goal was to determine their knowledge on these topics and whether they would be interested in participating in a workshop that would provide 1- techniques to reduce or eliminate human pathogen contamination from soil and 2- practices that would improve soil health. A total of 71 evaluations were performed, with 85% of responses coming from growers from North Carolina, 6.3% from Georgia and 7.9% from Tennessee. Changes/Problems:We have reported in last year's annual repot the major challenges we faced with lab personnel and the health-related issues of the PI of the grant. The only modification we had to make to the project was that all stable isotope-probing (SIP) experiments we performed using only Salmonella and we didn't perform any SIP studies with Listeria monocytogenes. Timelines and resources didn't know permit to include these other organisms as originally planned. Further the PI of this grant provided in financial support to this project in the vicinity of 50K because of the issues we faced with disruptive lab personnel that wasted salaries and supplies linked to the project. We have finished all project activities and we are currently finishing two sequencing runs and once data has been compiled and analyzed all other information will be used for publication. What opportunities for training and professional development has the project provided?This project has not provided opportunities for training and professional development of the target audience as we first needed to gather the data needed to inform the development of a workshop that would address human pathogen die-off under field conditions and soil health. Now that we have completed the project and papers are submitted for publication our next step will be to request funding to develop those training opportunities. However, it has allowed 4 students to interact with the farming community and to later present their research findings at international conferences, bring in these venues' real-life perspectives from those individuals dealing with farming activities, food safety practices and potential problems and extension agents that interject between the farmers and the research community. These immersion in farming, microbial food safety research and farmer behavior has led these students to pursue careers in food safety. Two of them are now working with companies growing and processing leafy greens or providing food safety training, one of them is pursuing her PhD in food safety with an emphasis in fresh produce safety and the other decided to move into biotechnology, citing that "in fresh produce food safety there are too many variables to effectively and rapidly resolve farmer and consumer issues". We believe this statement reflects how many seasoned growers fill about food safety and that is moving them to other crops or ventures. Recommendations for Future Extension Activities Finally, participants were asked about their interest in attending an Extension training program that would address soil health management and reducing contamination of soil with human pathogens. Most respondents (71.4%) indicated that they would be interested in attending such training. In addition, several respondents provided feedback about the specific topics that they would like addressed in this training. The need for more, general, information about soil health, practical approaches for maintaining and improving soil health, and reducing contamination of soil with human pathogens. In addition, several respondents specifically noted that they would benefit from additional training about soil pH management, details about how fertilizers affect soils, the relationship between pest control and soil health. How have the results been disseminated to communities of interest?As of this moment the results from our project have been disseminated in two international events; the 2018 and 2019 IAFP meetings. In both meetings posters and presentations with updated results have been provided to the audience. The two abstracts that were submitted and accepted are the following: Soil Bio-remediation Practices to Reduce Salmonella Contamination in Melon Production Systems. (2018). Brianna, R., Gunter, C., Thakur, S., and Gutierrez-Rodriguez, E. IAFP conference Salt Lake City, Utah. Bio-Remediation Practices to Reduce Human Pathogen Contamination from Agricultural Soils. Young, M., Knueven, C., Thakur, S., Gutierrez-Rodriguez, E. IAFP conference, Louisville, KY. Once this report is completed and all sequencing and survey data is analyzed we will prepare at least two publications from this project. We hope to have one publication ready for review by the end of 2019. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Impact This project specifically focused on leafy greens - cantaloupe crop rotation, because of the seasonality and the economic importance of these crops to farmers and because of the number of food-borne outbreaks associated with these crops. Results provided initial data to explore a major problem in agricultural systems that is related to enumerating, reducing or eliminating the presence of Salmonella or Listeria monocytogenes (LM) in soils used for fruit and vegetable production. Specific to the achievements of the project we were able to begin describing the prevalence of LM on three distinct agricultural regions in NC. This is important because it provides the baseline of the potential distribution of LM in soils used for fruit and vegetable production and forms the basis for risk analysis linked to the potential contamination of fresh produce with LM. From our evaluations we were able to recover LM from all 3 regions in NC, with the highest recovery observed at the Piedmont Research Station (PRS) and the lowest recovery from the Coast Plains Research Station (CPRS). Both of these locations have contrasting soil characteristics mainly based on soil pH, nitrogen content and organic matter. Soil pH at the PRS is on average equal to 7.2 while at the CPRS the pH on average is equal to 4.1. Such difference in soil pH has also been linked in other regions and soils as the main driver in the presence and distribution of bacterial communities and pathogens in soil. It is important to clearly define that this is just the first step in the process and that the prevalence of LM on these locations may not reflect the prevalence and distribution of this pathogen on all agricultural land used for growing fresh produce in NC. Both prevalence and distribution are impacted by growing practices, cultivars and regional conditions as it was determined by our soil-LM survey. Overall, from all 3 locations we were able to determine that the greatest impact on our ability to recover LM was associated with proximity to animal operations, highest clay content and cooler weather conditions. This project also provided insight into the microbial interactions in soil between Salmonella and all other bacterial communities present in organic and conventional melon production practices. These experiments were performed in 5-gallon intact mesocosms brought from agricultural land used for organic and conventional melon production. We used and refined a microbial ecology technique known as Stable Isotope Probing (SIP) to determine microbial interactions between soil microorganisms and Salmonella. The importance of these experiments resides in our ability to clearly identify those bacterial groups interacting with Salmonella. Previous microbial community studies based on DNA sequencing have only been able to catalog the presence of different bacterial organisms, without being able to clearly identify which ones are really interacting with this pathogen. From all bacterial groups analyzed four of them, specifically Bacteriodetes, Plantomycetes, Proteobacteria and Verrucomicrobia significantly increased in the presence of Salmonella. With the information gathered on these experiments we can now begin asking further specific questions as to which of those organisms suppress, consume or enhance the survival and persistence of Salmonella in soil. Such questions will be the focus of future research proposals. Finally, this project also addressed farmers' knowledge gaps, concerns, and behaviors regarding the contamination of soils with human pathogens and potential practices to reduce or eliminate the presence of these transitory colonizers of soils used to grow fresh produce. We developed a survey that aimed to create a baseline of the knowledge gaps linked to soil health and food safety. In developing this instrument, we determined the cost of implementing solarization, cover cropping, application of compost, or a combination of these techniques as well as the projected microbial reduction resulting from each of these techniques. This information was presented to growers during the survey and their feedback was requested to determine which technique or combination of techniques would be preferred based on the dollar value and microbial reduction. A majority of these growers were based in NC, but growers from TN and GA also participated, In evaluating these responses, it was found that, while most farmers indicated that they were familiar with the risks associated with human pathogen contamination of fruits, vegetables and soil, none were aware of any techniques which could be used to remedy this problem. Further, while several options to reduce the number of human pathogens in soil have been developed, very few of our study participants indicated that they would be willing to pay the cost of addressing this problem. Overall, these results indicate that a very significant outreach effort will be needed to educate growers about the financial and other risks of human pathogens to their fruit and vegetable production, and bio-mitigation strategies which may help reduce loads of these pathogens in agricultural soils. Fortunately, results indicate that most of the surveyed growers (80.6%) do obtain soil health information from university extension services or farmers' associations. Through these channels, and targeted dissemination of information to those working in positions where farmers also seek this type of information (e.g. wholesalers, distributors and chemical sales reps) it should be possible to reach growers with timely and correct information about soil health management and risks
Publications
- Type:
Other
Status:
Accepted
Year Published:
2018
Citation:
Soil Bio-remediation Practices to Reduce Salmonella Contamination in Melon Production Systems. (2018). Brianna Reed, Chris Gunter, Siddhartha Thakur, and Eduardo Gutierrez-Rodriguez. IAFP conference Salt Lake City, Utah.
- Type:
Other
Status:
Accepted
Year Published:
2019
Citation:
Bio-Remediation Practices to Reduce Human Pathogen Contamination from Agricultural Soils. Young, Morgan., Knueven, C., Thakur, S., Gutierrez-Rodriguez, E. IAFP conference, Louisville, KY.
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Progress 01/01/17 to 12/31/17
Outputs
Target Audience:The target audience here was divided in four groups: 1- First group looked to evaluate the preferences of growers regarding farming practices. Specifically, we did small survey type events to determine which were the best questions to be used when assessing adoption of farming practices. These farming practices were specific to solarization, cover cropping and the use of compost within their produce rotations and we also determine what was the basic level of knowledge associated with food safety. We pilot these activites at two meetings; the southeastern tomatoe meeting and the southeastern vegetable grower meeting. 2- Second target audience was resear station farm managers that are responsible for growing crops under typical commercial growing conditions. At the Cherry creek research station located in Goldsboro, NC we explored potential methods for preparing fields for melon production using the proposed remediation practices. Specifically, the use of solarization, cover cropping and compost. We performed two small trails but both were consumed by flooding and pests due to adverse weather conditions and issues between the postdoc and the farm employees at this location. Based on this conditions we moved all experimental activities to small plot areas located in an area protected from flooding in which we could test the application of these techniques at very small scales. 3- Our third target group was greenhouse managers at the phytotron where we would grow melons and test survival and persistence of Salmonella typhimurium grown with 13C labeled glucose. Due to issues with the postdoc and the phytotron we were not able to complete these experiments and access to this unit was halted until all issues were resolved. Further during this same period the PI of the project in charge of the microbiological experiments had to deal with some personal issues that require intermitent absence from work for a period of 6 months. For these reasons a no cost extension was requested. 4- Our final target group was farmers growing produce that could allow us to determine the prevalence of Listeria monocytogenes in soil. Although originally we were allowed to collect samples and performed initial tests, this permission was later canceled due to the concerns associated with contamination of Listeria monocytogenes. Changes/Problems:We faced a number of problems during this period that resulted in the request of a no cost extension. These problems were the following: 1- Postdoc issues with members of the BL3 greenhouse that resulted in lose of all BSL3 experiments, access to BSL3 was halted and the postdoc left the lab without notice. 2- The PI of the grant had to deal with a personal problem during 6 months that prevented him from being directly involved with all aspects of the project. 3- Initial field trials where we tested the implementation of the proposed practices were lost due to adverse weather conditions, high pest incidence and additional issues between the postdoc and farm personnel. 4- Although we originally had access to two commercial farms that would allow us to test for Listeria monocytogenes, this permission was later canceled due to concerns with the presence of these pathogen in soil. Changes for the next reporting period: 1- Small scale field trials will be repeated to establish whether the proposed practices are feasible. These plots will be used to collect mesocosms that will be used in the BSL3 unit. 2- Wait time for IRB might be longer than expected and thus we might not be able to perform all evaluations until later in the year. 3- Access to the BSL3 unit may not be possible, therefore we have build another greenhouse under BSL2 conditions that could be used to perform the evaluations of the survival and persistence of 13C labled Salmonella typhimurium and the potential interactions with the soil microbila community. 4- Soil survey for Listeria monocytogenes will focus only on 4 research stations in NC distributed along the state and that grow fresh produce under commercial practices. What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?Our plan for the next reporting period is the following: 1- Finish the implementation of small scale melon trials at the research station. This very small plots will be used to collect soil mesocosms with the desired soil and selected compost and cover crop treatments. 2- We will finish the survey and submit IRB for approval. 3- We will repeat growth studies of Salmonella typhimurium needed for 13 C labeling and we will use this information to growth the selected strains and inoculate them in the mesocosms collected from the small field trials and brought back to the BSL3 greenhouse. 4- We will continue our testing of soil samples for Listeria monocytogenes from all 4 research stations and provide an estimate of the prevalence of these pathogen at this locations.
Impacts
What was accomplished under these goals?
During this period of time we were able to accomplish the following: 1- Develop the frame work needed to implement a grower driven survey that would address the use of solarization, cover crops and compost and a basic understanding of the knowledge of growers specific to food safety. 2- We experimented under field conditions the application of compost and cover crop seeds and how we could prepare field beds for melon growing practices that would allow us to bring mesocosms from the field to the BSL3 greenhouse and the potential costs for growers trying to implement these practices. 3- Although our BSL3 studies were not completed because of the reasons stated before, we were able to understand the watering needs for melon plants and the Salmonella typhimurium growing conditions needed for 13 C labeling. 4- A small survey of the presence of Listeria monocytogenes was performed on farm land used for fruit and vegetable production. We only gain access to 4 research station farms that grow produce under comercial practices and those were used to determine the incidence of these pathogen. This small survey indicated the prevalence of this pathogen in 3.2 % of the samples. We also gain access to 2 commercial farms but we were not allowed to test for the presence of any pathogen.
Publications
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