Progress 09/01/09 to 08/31/14
Outputs
Target Audience:During the final reporting period, the target audiences reached by this project included fresh produce growers, processors, and distributers, and academic researchers. Fresh produce growers, processors and distributers were reached through a series of workshops and symposia. The first workshop took place at the annual Ohio Produce Growers and Marketers Association (OPGMA) annual meeting where a panel discussion regarding the microbial risks associated with fresh produce growth and harvest was held by the PI (Goodridge) and coPIs (Danyluk and Suslow). The PI (Goodridge) also presented two talks on the topics of foodborne outbreaks likned to fresh produce, and leassons learned from recent fresh produce outbreaks. A cantaloupe safety symposia hosted at Colorado State University by the PI (Goodridge) and others associated with the project (PI Bunning) led to interactions with Colorado fresh produce growers and processors, where topics related to microbial growth,and control on fresh produce was discussed. Growers and processors were also reached through two interviews that PI goodridge gave to media regarding fresh producesafety. Finally research related to this project was presented at the International Association for Food Production Annual Meeting. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project providied significant opportuntiies for training of graduate students and post-doctoral fellows. Three PhD students and three MS students completed their educational trainingby completing research projects related to this project. In addition, two post-doctoral fellows also conducted research on this project. The graduate students, postdoctoral fellowsand the PI and coPIs of this projecttravelled to national and international meetings as well as meetings of fresh produce industry trade associations andpresented the results of this research, in addition to organizing symposiafor fresh produce growers and harvesters, and making visits to fresh produce farms to answer fresh produce safey related questions that the producers had. How have the results been disseminated to communities of interest?These results have been disseminated to the communities of interest in the following ways: for growers and processors of fresh produce, the results were disseminated through on farm visits, workshops and symposia at regional ans national trade association meetings. The results have also been disseminated to the academic communtiy through presentations at national food safety conferences, and through peer reviewed publications. Dissemination results to all interested stakeholders is ongoing. 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 has contributed knowledge to the understanding of the microbial risks associated withthe growth and harvest of tomatoes inseveral mainareas including:1. Understanding the presenceof Salmonella inwater used for agricultural operations and determining the risk of contaminationof tomatoes from such sources; 2. The development of models for use in predicting the presence of Salmonella in agricultural waters; 3. Determining the ability of Salmonella to survive in pesticide and fertilizer solutions under different storage conditions; and 4. Evaluation of risk factors affecting transmission and persistence of Salmonella spp. in hydroponically grown tomatoes. With respect to the above areas, it was learned that: 1. Multiple serotypes of Salmonella can persist for long periods in surface water, and many serotypes that do not seem to contribute to human cases of Salmonellosis are often found in surface waters used for agricultural operations; 2. When Salmonella is present in surface waters in Florida (a major tomato growing region), logistic regression analysis showed that Escherichia coli concentration can predict the probability of enumerating selected Salmonella levels. In general it was observed that there was a lack of good correlations between biological indicators and Salmonella levels and between physicochemical indicators and Salmonella levels, whichshows that the relationship between pathogens and indicators is complex. However, E. coli provided a reasonable way to predict Salmonella levels in Central Florida surface water through logistic regression; 3. Salmonella can survive at least 7 d in groundwater and some of the foliar pesticides tested. Spray tanks left over extended periods may be a potential source for pathogen contamination into produce fields; 4. Contaminated hydroponic nutrient solution or water leads to Salmonella contamination of tomato plat roots, but such an event may not pose a risk of Salmonella contamination of hydroponically grown tomatoes.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Predicting Salmonella populations from biological, chemical, and physical indicators in Florida surface waters. McEgan, R., Mootian, G., Goodridge, L.D., Schaffner, D.W., and Danyluk, M.D. Applied and Environmental Microbiology. 79:4094-4105.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Diversity of Salmonella isolates from central Florida surface waters. McEgan, R., Chandler, J. C., Goodridge, L. D., Danyluk, M. D. Appl Environ Microbiol. 80:6819-6827.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2012
Citation:
The Fate of Salmonella Typhimurium in Foliar Fertilization Solutions in Groundwater under Different Storage Temperatures. A. Valadez, Goodridge, L., and Danyluk, M. 2012. International Association for Food Protection 98th Annual Meeting, Providence, Rhode Island.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2012
Citation:
Chemical, Physical and Biological Indicators for Salmonella spp. in Central Florida Surface Waters. R. McEgan, Mootian, G., Goodridge, L., Schaffner, D., and Danyluk, M. 2012. International Association for Food Protection 98th Annual Meeting, Providence, Rhode Island.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2013
Citation:
The Fate of Salmonella Serovars in Foliar Pesticide Solutions under Different Storage Temperatures. A. Valadez, Goodridge, L. D., and Danyluk, M. 2013. Institute of Food Technologists Annual Meeting and Food Expo, Chicago, Illinois.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2014
Citation:
Salmonella Serotypes in Central Florida Surface Waters. R. McEgan, Chandler, J., Goodridge, L., and Danyluk, M. 2014. International Association for Food Protection Annual Meeting, Indianapolis, Indiana.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2014
Citation:
Evaluation of Risk Factors Affecting Transmission and Persistence of Salmonella spp. In Hydroponically Grown Tomatoes. S. Coleman, Bisha, B., Blume, K., Sandoval, V., Drury, N., Kesseler, H., Perez-Mendez, A., Chandler, J., Bunning, M., Newman, S., and Goodridge L. 2014. International Association for Food Protection Annual Meeting, Indianapolis, Indiana.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2014
Citation:
Isolation and Characterization of Salmonella from North Florida Surface Waters. T. Chapin, Mootian, G., McEgan, R., Reddy, S., Friedrich, L., Chandler, J., Goodridge, L., Danyluk, M., Schneider, K., and Schaffner, D. 2014. International Association for Food Protection Annual Meeting, Indianapolis, Indiana.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2014
Citation:
Control of the Microbial Quality of Cantaloupes via Employment of a Processing Line Incorporating Chlorine Dioxide as an Intervention Step. J. Chandler, Perez-Mendez, A., Coleman, S., Manley, W., Danyluk, M., Bunning, M., Goodridge, L., and Bisha, B. 2014. International Association for Food Protection Annual Meeting, Indianapolis, Indiana.
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Progress 09/01/11 to 08/31/12
Outputs
OUTPUTS: Several outputs were achieved during the current reporting period. Specifically, several activities (experiments) and an event were completed. The experiments led to a change in knowledge regarding understanding of the survival of Salmonella in tomato field soils during the off-season of tomato production. Other experiments led to knowledge with respect to the Salmonella serovars that are found in the tomato production environment, and also the best molecular methods to determine the serotyes of environmental Salmonella islolates. The event was a talk that was given at a symposium for USDA National Integrated Food Safety Initiative Special Emphasis Projects. This symposium allowed the research team to disseminate results associated with this project to interested stakeholders. PARTICIPANTS: Lawrence D. Goodridge, Michelle D. Danyluk, Trevor S. Suslow, Donald Schaffner, Alex Castillo, Elliot Ryser. Training of graduate students as part of this project is ongoing. So far several students have been trained and mentored, including Rachel McEgan, Adrian Sbodio, Shannon Coleman, and Gordon Davidson. TARGET AUDIENCES: The results of this project have been communicated thus far to vegetable producers in the form of t above mentioned workshop, on farm visits, and extension presentations. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Taeget audiences were fresh produce growers and processors. Several events were conducted in order to disseminate results and cause a changein knowledge. One event was talk that was given at a symposium for USDA National Integrated Food Safety Initiative Special Emphasis Projects. Other events includedon farm visits, and extension presentations. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The time between tomato harvest and field preparation for the next crop of tomatoes can range from two to five months, depending on the production district. The risks associated with Salmonella survival during the off-season of tomato production have not been investigated. experiments were conducted to investigate the potential for Salmonella to persist in tomato field soil with and without the addition of tomato plant debris. A cocktail of rifampicin-resistant Salmonella serotypes were inoculated at high and low concentrations into soils collected from four tomato-growing regions in Florida. The soils were further divided into four composites. Soils were stored at 15C or 30C for 3 months. Salmonella populations were enumerated on rifampicin supplemented selective and non-selective agars. At 30C, Salmonella populations declined in tomato field soils. After 90 days, populations were detectable in all conditions evaluated by enrichments of 10 g samples. These results show that Salmonella can persist in Florida's tomato field soils during the off-season of tomato production and may be a source for pathogen contamination in produce fields between tomato seasons. in other experients, we compared traditional serotyping to three molecular typing strategies, riboprinting, pulsed field gel electrophoresis (PFGE), and Luminex xMAP Salmonella Serotyping Assay (SSA) to characterize S. enterica. A diverse panel of food, outbreak, and environmental S. enterica isolates from tomato production environments were evaluated by Riboprinting using EcoRI and PvuII restriction enzymes, by PFGE using XbaI and BlnI, and by SSA. Results were compared to traditional serotyping. Strong agreement of serotyping results were observed for food- and outbreak-related S. enterica isolates when comparing molecular typing strategies to traditional serotyping. Riboprinting and PFGE were in strong agreement with outbreak isolates of S. Enteritidis and S. Typhimurium. Molecular serotyping outperformed traditional serotyping in several instances. Characterization of environmental isolates proved more problematic, with frequent discrepancies between molecular serotyping methods. Results from two of the three typing strategies were frequently identical for a particular isolate, and by combining the outputs of the different typing strategies, extremely accurate serotyping was possible. These results demonstrate that the majority of S. enterica serotypes can be effectively typed using molecular serotyping methods, and combining methods improves typing efficacy for environmental isolates, which may be difficult to characterize using traditional serotyping.
Publications
- Development of a Paper-Based Analytical Device for Colorimetric Detection of Select Foodborne Pathogens. Jokerst, J. C., Adkins, J. A., Bisha, B., Mentele, M. M., Goodridge, L. D., and Henry, C. S. Analytical Chemistry. 2012. 84:2900−2907.
- Framework for Developing Research Protocols: Evaluating Microbial Hazards and Controls during Production that Pertain to the Quality of Agricultural Water contacting Produce that may be consumed Raw. Harris, L. J., Bihn, E. A., Bender, J., Blessington, T.,Danyluk, M. D., Delaquis, P., Goodridge, L., Ibekwe, A. M., Ilic, S., Kniel, K., LeJeune, J. T., Schaffner, D. W., Stoeckel, D., and Suslow, T. V. Journal of Food Protection. 2012. 75:2251-2273.
- Assessment of Microbial Index Organisms as an Accurate Predictor for Salmonella spp. in Greenhouse Tomatoes. L. D. Goodridge. 2012. Institute of Food Technologists Annual Meeting and Food Expo. June 26th, Las Vegas, Nevada.
- Improving the food safety of fresh produce through modern sampling, testing and analytical techniques. L. D. Goodridge. 2012. Department of Animal Sciences, Colorado State University. April 27th, Fort Collins, CO.
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Progress 09/01/10 to 08/31/11
Outputs
OUTPUTS: One of the aims of this project is to investigate the food safety of hydroponically grwon tomatoes. During this period, we evaluated a FRNA phage assay to identify the presence of male specific RNA coliphages in water used in a hydroponic tomato growing facility. The presence of these phages in water has been previously associated with fecal contamination, as demonstrated in many studies. Furthermore, since there are four different groups of FRNA phages, depending on which FRNA phage group is found, one can determine the sources of fecal contamination. Water samples from a recirculating dump tank used for washing tomatoes were obtained on three different dates from a hydroponic tomato facility. In addition to tank water, samples of universal pre-enrichment broth used for washing individual tomatoes were collected during the second and third sampling. All samples at each date were packed in coolers with refrigerant bags and transported to the laboratory for analysis. Water samples from the tank (TW1) and from UPB rinsate of tomatoes (TW2 and TW3, up to 20ml of each sample) were mixed in a 50ml conical tube with an equal volume of 2x TSB supplemented with 5ug/ml of each ampicillin and streptomycin. After addition of 1ml of bacterial host (E. coli FAMP) culture, samples were incubated at 37 degrees C and shaking at 250 rpm overnight. A 50ul drop of the culture was transferred on to a prepared seeded agar plate of E. coli FAMP and incubated overnight for the plaque assay. A positive sample produced a lysis zone or plaques in the inoculated spot of the plate. Enrichment was accomplished by adding to each sample 0.05g/l of sodium thiosulfate to neutralize chlorine from the dump tank water, followed by incubation overnight at 37 degrees C. This was followed by RNA isolation and RT-RT PCR to detect the FRNA phages. Results indicated the presence of FRNA phages from group III in 9 samples. It was possible to detect, by molecular and traditional methods, FRNA phages in water used in this tomato facility, suggesting contamination of fecal origin. As most detected phages were from FRNA group III this contamination may be of human origin. The fact that a higher percentage of positive samples were found in UBP rinse than in tank water indicate that rinsing tomatoes with UBP is a good way to look for contamination. PARTICIPANTS: Participants involved in the research project include: Colorado State University: Lawrence D. Goodridge, Shannon Coleman, University of Florida, Michelle D. Danyluk, Racel McEgan, University of California Davis: Trevor S. Suslow, Adrian Sbodio, Rutgers University: Donald Schaffner, Michigan State University: Elliot Ryser, Gordon Davidson. Training of graduate students as part of this project is ongoing. So far several students have been trained and mentored, including Rachel McEgan, Adrian Sbodio, and Gordon Davidson. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The findings from the research conducted during this period indicate that the use of FRNA phages as indicators of fecal contamination may be a usful aproach to monitor tomatoes produced hydroponically for human fecal contamination, sicne there should be no animal contamination due to the closed system. The data from the sampling will be used to later perform risk analysis of hydroponic tomato production and will be applied to assess production practices (harvesting practices, i.e. use of lack of gloves).
Publications
- No publications reported this period
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Progress 09/01/09 to 08/31/10
Outputs
OUTPUTS: A method was developed to screen large volume (10 L) samples of surface water used for irrigation of produce, for the presence of Salmonella. The total time required for the developed screening method is three days. We are able to detect 1 CFU/L in a 10 L sample of surface water. Six public access surface water sampling sites, in each of three counties, in central Florida were identified. A twelve month sampling survey has begun; 5 months are completed. All samples screening positive for Salmonella have been assessed by the FDA-BAM method for Salmonella MPN, with one modification - XLT4 and Salmonella Plus ChromAgar are used for the solid agar step rather than BSA, XLD or HE. The Salmonella MPN was undertaken so that this study determines not only frequency of Salmonella positive samples, but also the concentration of Salmonella in a positive sample (i.e. how positive is the positive sample). In addition to detecting Salmonella, other characteristics and parameters of the surface waters are being monitored including: aerobic count; coliform/ E. coli MPN; water and air temperature; water pH and oxidation reduction potential; water turbidity; and water conductivity for all sampling sites. PARTICIPANTS: Lawrence D. Goodridge, Michelle D. Danyluk, Trevor S. Suslow, Donald Schaffner, Elliot Ryser. Training of graduate students as part of this project is ongoing. So far several students have been trained and mentored, including Rachel McEgan, Adrian Sbodio, and Gordon Davidson. TARGET AUDIENCES: The results of this project have been communicated thus far to vegetable producers in the form of on farm visits, and extension presentations. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
It was demonstrated that the best screening methodology is to use a combination of tangential flow filtration, overnight enrichment in double strength lactose broth, Pathatrix immune-magnetic separation, DNA extraction with Mobio's UltraClean DNA isolation kit, and real time PCR using a Salmonella detection kit. Three counties in Central Florida were identified and six sites in each county were selected. The criteria for site selection included: public access, ease of sampling, near to non-animal agriculture. Advice from other faculty was solicited. The data from the 12 month sampling will be used to later perform risk analysis which can be applied to agricultural waters. Five months of sampling has been completed and data is currently being evaluated.
Publications
- McEgan, R., L.D. Goodridge and M.D. Danyluk. Detection and Isolation of Salmonella from Surface Waters. Food Micro Conference, Copenhagen, Denmark, 2010.
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