Annette Kenney, a candidate for a master’s degree in Food and Agriculture Sciences with a concentration in plant and soil science, defended her thesis entitled, “Assessing Escherichia coli Survival in Manure-Amended Certified Organic Soils Cultivated with Tomatoes, Radish, and Spinach on the Eastern Shore of Maryland,” December 13. Kenney is a native of the Eastern Shore of Maryland who calls Marion Station home.
According to Kenney and her advisor Dr. Fawzy Hashem, an associate professor in the Department of Agriculture, Food, and Resource Sciences, more scientific data is needed to guide development of on-farm practices that support food safety of fresh produce. Current National Organic Program standards stipulating a 90-120 day wait-period between manure application to cropland and crop harvest “remain a concern.” The main goal of this study, they said, was to assist in determining appropriate application intervals for biological soil amendments of animal origin on organic fields.
“During my thesis research, we examined the survival and persistence of generic rifampicin-resistant E. coli (EC rif-R) in sandy loam soils amended with untreated animal manure (poultry litter, dairy manure slurry and horse manure) and cultivated with fresh produce (spinach, radish and tomatoes) on a certified organic research field at UMES’ Agricultural Research Station,” Kenney said. “Our research team hypothesized that the EC rif-R survival and persistence in certified organic soils producing fresh produce are associated with the type of raw manure used, harvested produce and wait-time intervals.”
The populations of EC rif-R surviving at each sample date fluctuated over the two-year period in all manured and un-amended soils treatments for the three vegetable crops and persisted longer in some manures amended organic soils than others, she said. Weather condition may have been a factor in the variability.
“This study, specific to certified-NOP soils, will contribute to risk-based assessments for development of application-to-harvest wait-time intervals for fresh produce safety,” Kenney said.
“Ms. Kenney has been working with me for over five years as an undergraduate student and graduate student. During these years, I have found Annette to be a hard working team leader and very dedicated individual. She gets along well with her peers, fellow students and professors. She collaborated positively with scientists from USDA-ARS and from the University of California, Davis,” Hashem said.
Kenney has won several national and international awards and recognition for her outstanding research on the microbial food safety of fresh produce, including a first place poster award given to her in 2016 by the American Society of Horticultural Sciences.
She plans to continue her education at UMES following her December graduation. Kenney will pursue a doctoral degree in the Food Science and Technology Program under the direction of Hashem.
