Significant problems have occurred in the U.S. with regard to the contamination of produce by pathogenic bacteria. Minimally processed produce lacks the processing and preparation hurdles, such as cooking, to aid in reduction or elimination of the occasional and incidental contamination that can lead to widespread outbreaks and national product recalls. Greater emphasis has been placed on preharvest Good Agricultural Practices and postharvest Good Manufacturing Practices, but the American food production and distribution system is vast, complex and global. Environmental fecal contamination is not uncommon in these foods, and transmission of human pathogens to plants through contaminated irrigation water has been documented under both laboratory and field conditions. <P>
This project proposes to develop and evaluate a high-volume treatment for irrigation water utilizing filtration through columns of zero-valent iron (ZVI) and sand. ZVI has been successfully used for over ten years in commercial water treatment operations to remove chemical contaminants. Evidence has described the adherence and inactivation of viruses and Escherichia coli by ZVI used in water treatment. <P>
The objective of this project is to optimize removal of E. coli O157:H7 and Salmonella from water treated by passage through ZVI-sand columns under conditions modeling commercial use.