Submitted to: American Society for Microbiology Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 2000
Publication Date: N/A
Technical Abstract: The influence of manure application and cover crops on E. coli O157:H7 and total coliform survival was tested in three diverse soils using intact soil-core microcosms. Manure from a dairy operation was inoculated with O157:H7 and applied to one set of microcosms at 6 tons per acre. Separate sets of microcosms received only O157:H7 or only manure. The manured microcosms were then planted with rye or left fallow. Other microcosms receiving O157:H7 but no manure were planted to alfalfa, crimson clover or hairy vetch. Survival was assessed by extracting the cores and sampling roots separately from the bulk soil. In soil with or without added manure O157:H7 survived up to 30 days. Enhanced O157:H7 survival was seen on rye roots in all soils, to 53-56 days. Results for other rhizospheres were less consistent. In a silt loam soil, alfalfa rhizospheres enhanced survival to 64 days. In a clay loam and sandy loam soil, rhizospheres other than rye did not enhance survival. When manure was present, total coliforms survive 79-86 days in soil and 25-69 days in soil without manure. In conclusion, E. coli O157:H7 applied with manure, or through irrigation and runoff, survives for 1 month in fallow soil and up to 2 months in the presence of various cover crops. In addition, coliforms applied with manure persist as long as 3 months, which may be an appropriate safety factor when considering cropping and land use decisions.