Irrigation waters as a source of pathogenic microorganisms in produce: a review

Authors: Pachepsky, Yakov; Shelton, Daniel; McLain, Jean; Patel, Jitu; Mandrell, Robert

Submitted to: Advances in Agronomy
Publication Type: Review Article
Publication Acceptance Date: 4/30/2011
Publication Date: 9/16/2011
Citation: Pachepsky, Y.A., Shelton, D.R., Mclain, J.E., Patel, J.R., Mandrell, R.E. 2011. Irrigation waters as a source of pathogenic microorganisms in produce: a review. Advances in Agronomy. 113:73-138.

Interpretive Summary: There is increasing evidence that consumption of raw fresh produce is a major factor contributing to human gastrointestinal illness. A wide variety of pathogens contribute to food-borne illnesses, including bacteria, protozoa and viruses. Incidence of food-borne pathogens on fruits and vegetables can be extremely high in some developing countries. However, substantial outbreaks also occur in developed countries. For example, produce related illnesses in the US cost an estimated $39 billion annually. Large-scale production of produce typically requires some form of irrigation during the growing season. There is a rapidly growing body of research documenting and elucidating the pathways of produce contamination by water-borne pathogens. However, many gaps still exist in our knowledge and understanding. Recent Food and Agriculture Organization and World Health Organization- sponsored workshops have concluded that the role of contaminated water used in the production of vegetable crops as a vector for the transmission of these pathogens to humans is not clear. The purpose of this review is to provide a comprehensive approach to the issue, including the most recent research from allover the world. This review will be useful for scientists and regulators responsible for water quality and food safety.

Technical Abstract: There is increasing evidence that consumption of raw fresh produce is a major factor contributing to human gastrointestinal illness. A wide variety of pathogens contribute to food-borne illnesses, including bacteria (e.g., Salmonella, pathogenic E. coli), protozoa (e.g., Cryptosporidium, Giardia), and and viruses (e.g., noroviruses). Large-scale production of produce typically requires some form of irrigation during the growing season. There is a rapidly growing body of research documenting and elucidating the pathways of produce contamination by water-borne pathogens. However, many gaps still exist in our knowledge and understanding. The purpose of this review is to provide a comprehensive approach to the issue, including the most recent research. Topics covered include: temporal and spatial variability, and regional differences, in pathogen and indicator organism concentrations in water; direct and circumstantial evidence for contaminated water as a source of food-borne pathogens; fate and transport of pathogens and indicator organisms in irrigation systems, and the role of environmental microbial reservoirs; and current standards for irrigation water quality, and risk assessment. A concerted effort by researchers and practitioners is needed to maintain food safety of fresh produce in an increasingly intensive food production system and limited and declining irrigation water resources.