Date of Graduation


Document Type


Degree Name

Master of Science in Horticulture (MS)

Degree Level





Maria E. Garcia

Committee Member

Michael R. Evans

Second Committee Member

Angela M. Shaw


E. coli, Food Science, Horticulture, Hydroponics, Lettuce


The Food and Drug Administration (FDA) have set new standards that apply to agriculturalists producing crops eaten fresh and/or raw by consumers. This new produce safety rule, known as the Food Safety Modernization Act (FSMA), has established science-based standards for all areas of production in agriculture with regards to microbial contamination. Escherichia coli (E. coli) O157:H7 is a particular bacterium of concern under FSMA guidelines. Grower compliance is mandatory and therefore vital to the continuation of any farm. Greenhouse hydroponic growers have shown advantages in efficiency when compared to conventional farming methodology. Those, however, with recirculating hydroponic systems face unique challenges when faced with a foodborne bacteria like E. coli. Recycling water also recycles pathogens, which can lead to complete crop infection. Traditional methods of eradication are complex and costly. Saponins are natural non-ionic detergents occurring as secondary metabolites in a multitude of plant species. Saponins exhibit many biological properties, one of which is as an antimicrobial. In this study we sought to examine the antimicrobial properties of saponins on E. coli and how it relates to plant growth and development of ‘Rex’ lettuce in a hydroponic NFT system.