Survivability of Bovine Derived Escherichia coli Subjected to Temperatures Typical of Summer in Texas

Abstract

Dairy manure and wastewater is often stored in lagoons and applied to fields during summer months.  The objective of this study was to determine the affect of moderate durations of typical Texas summer temperatures on the survivability of E. coli in dairy manure.  Manure samples were collected from two dairy operations and assigned to one of three temperature treatments, 73 °F, 95 °F, or 111 °F.  Manure samples were analyzed for E. coli on d 10 and d 21.  By d 10, reductions of 0.79 and 5.01 log units of E. coli occurred in manure samples stored at 95°F and 111 °F, respectively.  Survivability of E. coli populations at d 10 varied by farm for samples stored at 73 °F.  All samples showed significant reductions in E. coli populations after 21 d.  On d 21, E. coli bacteria in manure stored at 111 °F were undetectable, and E. coli concentrations averaged 0.63 and 3.87 log CFU/g for the 95 °F and 73 °F treatments, respectively.  Survivability of bovine derived E. coli was reduced by temperatures that are typical of summer in Texas.  Application of manure to agriculture land in Texas during periods of high environmental temperatures may facilitate a quicker decline in E. coli concentrations.