Progress 09/01/08 to 08/31/12
Outputs
Target Audience:
Nothing Reported
Changes/Problems: All the goals were accomplished before the last year of the project. However, I (principal investigator- Fonseca) was on leave of absence since late 2011 and left the Institution (University of Arizona) right after the leave of absence, reason for the delay in providing this final report. What opportunities for training and professional development has the project provided? The fact that all of the information was disseminated through extension meetings tailored to agriculture professional evidenced the importance for professional development. In Yuma, information was even used to outreach food safety managers in the industry. How have the results been disseminated to communities of interest? Presentations at industry meetings, trade journals, academic courses and scientific forums. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Key information for the agriculture industry in the US southwest was generated as we worked to reach the goals of the project. The main accomplishments are summarized below: - While some pharmaceutical residues were found in plants grown in greenhouse, the amounts found in the main surface water channels were always below 10 ng/L and most frequently below detection. Moreover, in commercial conditions none of the evaluated contaminants were found in crops irrigated with Colorado River water. - On another subject, the analysis of pathogens in the same irrigation water showed that the pathogens can survive for up to 30 days in water under certain conditions. The results suggest that if water used for irrigation is contaminated, there is potential for fresh produce such as leafy greens to get contaminated as well. However, we also have confirmed that production of leafy greens in the area is done when levels of bacteria in the water are lowest (winter time). - It is unclear why certain "jumps" in the bacteria population of the irrigation water occur. One hypothesis is associated with one of the goals: the presence of birds nearby irrigation canals. Our work, however, showed that no bird (of over 300 captured) shed a pathogenic bacteria. At least 1/4 did show non-pathogenic E. coli that may cause mislead analyses, especially if considering that growers are only requested to analyze for generic bacteria. As an interesting fact, the birds captured were all small creatures, and growers of the regions showed evidenced for samples sourced from large birds that did show the presence of Salmonella sp. This was an observation in only one year during the project, so it would need to be confirmed in the future. In field survival studies using a non-pathogenic surrogate we observed persistence of E. coli in commercial fields is dependent on the time of the year. Factors such as temperature, moisture and light (quality and intensity) may play an important factor for the survival. We also observed pathogens in water with more salinity, still used for irrigation water, declined more rapidly. Potential distribution of pathogens (E. coli surrogate) in a field, soil or plants, will vary significantly depending on the irrigation system. Overhead sprinkle irrigation will cause higher survival in plants while furrow irrigation tend to allow bacteria to survive in soil for longer time. All of the above information have been considered for other project studies and have been used by the industry for adapting measurements.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2011
Citation:
Fonseca, J.M., S. Fallon, C.A. Sanchez, K. Nolte. 2011. Escherichia coli survival in lettuce fields following its introduction through different irrigation systems. Journal of Applied Microbiology. 110: 893-902.
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Nolte, K., Sanchez, C.A. and J.M. Fonseca. 2011. Assessing the culture of fresh produce safety within a leafy green producing community. Journal of Extension. 12: 4 (6IAW4).
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Fox, B.K., C.S. Tamaru, J. Hollyer, L.F. Castro, J.M. Fonseca, M. Jay-Russel and T. Low. 2012. A preliminary study of microbial water quality related to food safety in recirculating aquaponic fish and vegetable production systems. College of Tropical Agriculture and Human Resources. University of Hawai at Manoa. Food Safety and Technology. FST-51
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Progress 09/01/10 to 08/31/11
Outputs
OUTPUTS: This year we emphasized on work done with contamination of different animal feces (including goat, dog, horse, cow, birds) on various water samples taken from the lower Colorado river basin. The target is to determine whether rates of two indicators may allow estimation of animal feces contaminating. Moreover, as comparison with last year's results we also sampled water from irrigation water in lettuce fields located in Colorado. Three microorganisms were used for this study: Salmonella Newport, E. coli O157:H7 and E. coli K-12. Water samples from 6 different locations in Colorado were inoculated with one of the test organisms and stored at room temperature or 12oC for 1 month. Two initial inoculum levels were used: 105 and 103 CFU/ml. Samples were taken at regular intervals, diluted, plated on appropriate media, and enumerated for the test organisms. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The results with water inoculation with animal feces showed mixed results. However, there was a pattern showing indicator rate levels for some species, particularly with dogs, may allow differentiation as to determine type of contamination. This finding is currently being tested as it suggests some dog feces in irrigation water canal may identified by simple use of indicators. In water sourced from Colorado at room temperature, there was 1 log population increase for all 3 tested microorganisms at day 1. For most of the samples, the population levels decreased eventually after day 1. At day 30, there were about 0-3 log reductions for S. Newport, E. coli O157:H7 and E. coli K-12. At 12oC, bacterial population decreased after day 3, and there were 0.5-3, 0.5-3.5 and 0-3 log reductions at day 30 for S. Newport, E. coli O157:H7 and E. coli K-12, respectively. There were differences in the survival among water samples from various locations, with higher survival rate in samples with lower electrical conductivity as was shown in other results in past years with water of the region. S. Newport survived better than E. coli O157:H7. The results showed that foodborne pathogens can survive in irrigation water for long periods of time and that survival can vary based on the locations. We initiated our outreach work participating in several conferences, workshops. Investigator Fonseca also developed a course online for students and any public that register through the University of Arizona outreach college, in which information generated in this project was included.
Publications
- Fonseca, J.M., S. Fallon, C.A. Sanchez, K. Nolte. 2011. Escherichia coli survival in lettuce fields following its introduction through different irrigation systems. Journal of Applied Microbiology. 110: 893-902.
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Progress 09/01/09 to 08/31/10
Outputs
OUTPUTS: We report here findings obtained during the first two years of this 4-year project funded by USDA. Our main goal has been to determine potential risks posed to the chemical and microbial quality of the Colorado river water. We also aimed to identify management alternatives to reduce risks. Up to date the project has produced important information to understand risk of pathogen in crop fields including plants, soil and irrigation water. We have validated the use of particular strains of E. coli K12 for field studies. One peer-review study has been published and one is under review, while several outreach has been done. The information of this project is well known in the southwest. Current research address the impact of feces, from different animal sources, in irrigation water if these were to contain a clinical pathogen such as E. coli O157:H7. The microbiological quality of the Colorado river was evaluated on a weekly basis. Up to date we have seen great variability in the population of bacteria indicators in the water (Fecal coliforms, total coliforms and generic E. coli), with low population coinciding with the production season of leafy green crops in Arizona. Higher population of bacteria indicator increase during warmer months when there is not production/harvest in Arizona. We have not seen any sample containing Escherichia coli O157:H7, a pathogen of great concern in the area. We assessed the risk posed by the different irrigation systems used, including overhead sprinkle, furrow and drip irrigation. We observed sprinkle irrigation is the method that poses the highest risk to deliver a contaminant to consumers. However, we also observed that furrow irrigation produces the longest survival of E. coli in the soil, which may eventually serve for cross contamination at harvest. In survival studies using a non-pathogenic surrogate we observed persistence of E. coli in commercial fields is dependent on the time of the year. Factors such as temperature, moisture and light (quality and intensity) may play an important factor for the survival. While survival of the bacteria was over two weeks in winter months, the persistence was not more than one week in summer months. In studies in Tucson we subjected Escherichia coli 0157:H7 and Salmonella sp. to survival studies in water collected from different sites along the Colorado river basin. We found that survival may vary depending on the concentration of salt in the water. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
This project has attracted good attention in the southwest given the fact that Colorado river water is the only source for irrigating leafy greens in the southwest. Our results have been disseminated in regional (Arizona, California) and international (Ireland, Mexico, Brazil) forums. We expect more attention to our results as we progress in the project.
Publications
- Fonseca, J.M., S. Fallon, C.A. Sanchez, K. Nolte. 2010. Escherichia coli survival in lettuce fields following its introduction through different irrigation systems. Journal of Applied Microbiology. 110: 893-902.
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Progress 09/01/08 to 08/31/09
Outputs
OUTPUTS: The survival of Salmonella enterica serovar Newport, Escherichia coli O157:H7 and Escherichia coli ATCC 25253 at room temperature and 12C was studied in various water samples from Yuma. At room temperature for all organisms, there was an initial growth (1-1.5 logs) in the first few days followed by a decline up to 30 days of sampling. At 4C, the bacterial populations remained constant for the initial 3-4 days followed by decline up to 30 days of sampling. We observed that in water with more salinity, still used for irrigation water, the pathogens declined more rapidly. We are currently looking at the presence of bacteria indicators in irrigation water in the Yuma area and the pattern is showing a decline during the winter months. Similarly, we have initiated sampling for pharmaceuticals and have started to identify some of common use. Finally, we are currently looking at how feces from various sources affect the bacteria indicator ratios and initial samples tend to show trends that need to be confirmed. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
These results showed that the pathogens can survive for up to 30 days in water under certain conditions and hence, if water used for irrigation is contaminated, there is potential for fresh produce such as leafy greens to get contaminated as well. These results help us understand the survival of pathogens (of concern in leafy greens) in irrigation water and can add to the knowledge needed for risk assessment of leafy greens irrigated with potentially contaminated water. We also have confirmed that production of leafy greens in the area is done when levels of bacteria in the water are lowest. However, we have observed "jumps" in population that indicates that growers, at random times, may not comply with current guidelines (Leafy Marketing Agreement). This will be confirmed with following sampling. Similarly, we consider on-going findings about various feces in different quality water will allow us to have a better idea of how contamination occurs in surface irrigation waters.
Publications
- No publications reported this period
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