Honors Theses

Date of Award


Document Type

Undergraduate Thesis



First Advisor

Colin Jackson

Relational Format



Samples of five different varieties of leaf vegetables obtained from a local supermarket were analyzed for the presence of bacteria on both the outside (epiphytic) and inside of the plant (endophytic). For each variety, both conventionally and organically cultivated samples were analyzed. Each sample was analyzed following a typical consumer wash (so detecting both epiphytic and endophytic bacteria), and also after being surface sterilized with 1:5 bleach solution (endophytic bacteria only). Viable counts on R2A and TSA agar suggested that the majority of the bacteria of leaf vegetables were epiphytic, and total numbers range from 10 To 10 CFU/g leaf material. A wide variety of both endophytic and epiphytic isolates were obtained from the various leaf vegetable varieties, although there was no consistent trend in the bacterial species obtained from the samples. Bacterial species isolated were primarily plant pathogens, plant symbionts, and soil or aquatic species, but also included possible human pathogens. These results show that salad leaf vegetables contain large numbers of bacteria and suggest that these bacteria interact with the plant and its environment.

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