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Data from: Biological Soil Amendments Can Support Survival of Pathogenic and Non-Pathogenic Escherichia coli in Soils and Sporadic Transfer to Romaine Lettuce

Published by Agricultural Research Service | Department of Agriculture | Metadata Last Checked: January 27, 2026 | Last Modified: 2025-06-30
Biological soil amendments are an essential input in organic lettuce production. However, these BSAs can introduce or transfer pathogens like Escherichia coli O157:H7 to lettuce in pre-harvest environments. This study evaluated the effect of BSAs on survival of non-pathogenic and pathogenic E. coli in soils and transfer to lettuce. Romaine lettuce was grown with controlled light, temperature, and relative humidity. Soil was amended (side-dressed) with either heat treated poultry pellets (HTPP), HTPP with corn steep liquor (CSL), seabird guano (SBG), SBG with CSL, or left unamended (UA). Soils were co-inoculated with non-pathogenic, rifampicin-resistant E. coli TVS 353 and two chloramphenicol-resistant E. coli O157:H7 isolates (100 mL of 106 CFU/mL). E. coli survival over 28 days was evaluated. On day 28, Romaine lettuce was harvested, and presence of E. coli was determined.

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