Interactions affecting the proliferation and control of human pathogens on edible plants

Pathogens on edible plants present a significant potential source of human illness. From 1991 to 2002, 21% of Escherichia coli O157:H7 outbreaks were from produce-related sources. E.coli O157 and other enteric bacteria can contaminate the surface of edible plants both pre- and postharvest. Some pathogens do not survive on the leaf surface or are removed by washing, but a significant portion of these enteric pathogens can persist on the surface and proliferate. Proliferation of these dangerous pathogens can increase the likelihood of foodborne disease associated with fresh or minimally processed produce. Several intrinsic and extrinsic factors determine the ability of enteric pathogens to attach and poliferate in the phyllosphere of plants. These include motility of the pathogen, leaching of nutrients by the plant, and interaction with epiphytic organisms. The interaction of enteric pathogens with the environment can lead to internalization into tissue, incorporation into biofilms, and genetic transfer. Current produce sanitation practices can reduce the microbial load from 1 log(10) to 3 log(10), so there are many new treatments possible. Understanding the ecology of enteric pathogens on plants is important to the development of sanitation methods and biocontrol agents. This knowledge can also assist the farmer in preventing contamination. With increasing consumption and importation of produce, its safety is a high priority for processors and the U.S. consumers. Food safety may be markedly improved with proper attention to pathogens on edible plants.