USDA-NIFA Organic Transitions Program. 3 year grant 2014-2017.
“Evaluating the effect of muskmelon cultivar and cover crops on soil biodiversity, and plant and human disease suppression during organic production”.
PI: Dr. Shirley Micallef
Co-PIs: Dr. Kate Everts, Dr. Gerald Brust, Dr. Yaguang Luo.
Cover crops and green manures impact soil microbial communities, but their influence on specific microbial community functions, such as nutrient cycling, plant growth promotion, phytopathogen and human pathogen suppression, and reduction of greenhouse gas emissions, remains unclear. As growers adopt organic practices and transition land from conventional management, it is crucial that they take advantage of the benefits of cover crops. This study will assess the effect of four green manure no-till cover crop systems on soil functions during cultivation of various cantaloupe cultivars, a valuable crop susceptible to both plant diseases and colonization by human foodborne pathogens. A multidisciplinary approach will integrate molecular microbiology, horticulture, phytopathology, food safety microbiology, entomology and food quality to answer questions on production, plant protection and microbial ecosystem services. Collaborations with USDA-ARS will allow for sensory and quality testing of new cantaloupe cultivars. A strong outreach program will develop new educational resources that extend research-based knowledge, which will be made available locally and nationally through a partnership with eOrganic.
USDA NIFA- AFRI. 3 year grant 2013-2016.
“Reducing On-Farm Enteric Pathogens Through Cropping Methods And Improved Food Safety Trainings”
PI: Dr. Shirley Micallef
Co-PIs: Dr. Clare Narrod, Dr. Abani Pradhan, Dr. Chris Walsh, Dr. Robert Buchanan and Dr. Debu Biswas.
Produce can be a vehicle for foodborne illness, but conditions which facilitate pre-harvest crop contamination are not fully understood. There are gaps in our knowledge on the influence of different soil management and cropping methods on pathogen survival in soil and transmission onto crops, hampering efforts to adequately educate farmers. This study is addressing pathogen ecology in integrated animal/crop-producing environments, and as influenced by a variety of cropping practices. Sustainable practices typically adopted by small-/medium-sized farmers in Maryland are being studied. Collected data can be used to develop a predictive modeling tool to predict pathogen fate under different management conditions. In addition, this study is evaluating current food safety trainings, to identify and address barriers to implementation of food safety plans, and their effectiveness in spurring food safety-motivated shifts in practices. This study is expected to yield new data on associations between cropping methods and pathogen survival, and identify effective teaching methods to motivate grower/marketers to implement robust food safety plans.
UMD ADVANCE SEED Grant 2014-2015.
“When tomatoes talk back: Salmonella-tomato plant interactions and pathogen growth responses to plant defense activation”
PI: Dr. Shirley Micallef
Co-PI: Dr. Wendy Peer
Salmonellosis caused by consumption of fruits and vegetables contaminated with the foodborne bacterium Salmonella is a significant food safety and public health concern. Controlling Salmonella contamination during the pre-harvest stage could minimize salmonellosis associated with tomatoes. This study evaluates the potential for tomato plants’ innate immune responses to impair Salmonella attachment, colonization or multiplication. Plants are able to mount defense responses against plant pathogens, an area of intense research, but we do not have a good handle on the mechanisms regulating the interactions between human pathogens and plants. A deeper knowledge of tomato plant-Salmonella interactions at the genetic and molecular level is fundamental for the development of innovative strategies that exploit plants own defense mechanisms. This study is assessing the involvement of the tomato plant defense system when associating with Salmonella, and evaluating the genome-wide gene expression patterns of Salmonella and tomatoes.