ATTACHMENT OF MICROORGANISMS TO FRESH PRODUCE

Authors: Mandrell, Robert; Gorski, Lisa; Brandl, Maria

Submitted to: CRC Press
Publication Type: Book / Chapter
Publication Acceptance Date: 1/1/2005
Publication Date: 4/1/2006
Citation: Mandrell, R.E., Gorski, L.A., Brandl, M. 2006. Attachment of microorganisms to fresh produce. CRC Press. p. 34-61

Interpretive Summary: Microbial ecology is crucial to plant life, and therefore, to the successful production of produce as a commodity. Plant microbes can be beneficial as symbionts, competitors of plant pathogens for biocontrol, and for promoting plant growth. However, plants also are vulnerable during growth to microbial pathogens in the environment (e.g. soil, water air, amendments). The links between fresh produce/produce dishes with more than 300 outbreaks in the US since 1990, and the obvious vulnerability of pre-harvest produce to pathogens in the production environment, have stimulated similar basic studies of the biology of enteric pathogens on produce. An ultimate goal of studies of attachment of human pathogens to plants is development of intervention methods to minimize attachment and survival of human pathogens. The goal of this chapter is to review current knowledge of perhaps the most important event that initiates the association between most microorganisms and plants: attachment. Studies that provide insight into fundamental molecular plant-microbe interactions have been emphasized. The studies reviewed provide a context for assessing the potential mechanisms of attachment of enteric human pathogens to produce. Minimizing human pathogens on produce will decrease the incidence of disease associated with produce, a desire of consumers, regulators and the produce industry.

Technical Abstract: The sources of the microorganisms exposed to plant surfaces may be from the plant seed itself, and through the initial contact with soil, irrigation water and air. The microbial ecology of the rhizosphere (roots and the part of the soil affected by contact with roots) and the phyllosphere (leaves and the environment in contact with leaves, e.g. water, air) of produce are in constant change due to factors that affect microbes, such as humidity, temperature, nutrients, UV radiation, insects, and wild animals. Plant tissues are in close contact with potentially thousands of different species of bacteria, viruses and other microorganisms. Fruit and vegetable crops also have a rich microbial flora, including in many cases, coliforms and fecal coliforms that are unavoidable considering domestic and wild animals near production environments. Human pathogens attach to plants and thus provide an area of investigation and for development of intervention methods to minimize survival of human pathogens. Studies that provide insight into fundamental molecular plant-microbe interactions have been emphasized in this chapter. The studies reviewed provide a context for assessing the potential mechanisms of attachment of enteric human pathogens to produce.