Submitted to: American Society of Animal Science Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: February 13, 2006
Publication Date: July 12, 2006
Citation: Wells, J., Berry, E.D., Varel, V.H. 2006. Effects of essential oils on viability of Escherichia coli O157:H7 in treated beef cattle manure slurries and on prevalence from treated feedlot surfaces [abstract]. Journal of Animal Science 84(Suppl 1):356-357. Technical Abstract: Escherichia coli O157:H7 is commonly found in cattle waste and its survival in manures is a concern for the environment and food safety. To determine the potential antimicrobial effects of different plant essential oil additives on this zoonotic pathogen, a selected strain of E. coli O157:H7 with known tolerance to the manure environment was inoculated into beef cattle manure slurry treatments (n = 3 reps/trt). Fresh feces were collected from pens of cattle fed a finishing ration (83% rolled corn), blended with urine and plant essential oil additives, and inoculated with streptomycin-resistant E. coli O157:H7 strain ATCC 43895. On d 0, a 1 g sample from each inoculated slurry was diluted and viable counts were determined by plating onto agar medium with streptomycin. Viable counts were determined daily until no longer detectable. In mixed slurries without additives, the decreases in viability of E. coli O157:H7 (death rate, -0.427 log10 colony forming units per gram feces per day) were similar and no viable counts were recovered after 12 d. Death rates of E. coli O157:H7 were 5.5-fold faster (P < 0.05) in manure slurries treated with thymol and were 2.8- to 2.9-fold (P < 0.05) faster in manure slurries treated with terpineol, geraniol, plinol, and glidox when compared to the non-treated control slurries. In further studies, terpineol and thymol applications were evaluated on feedlot surfaces (3 pens/trt) to control E. coli O157 prevalence over a 4-wk period in summer 2005. Terpineol application did not affect E. coli O157 prevalence in soil samples compared to untreated pens, but thymol application reduced prevalence by more than 50% (P < 0.05). These experiments suggest that some essential oils may control pathogens in cattle waste slurries and on feedlot surfaces. Additional studies with these compounds in the feedlot are needed to determine if higher concentrations and/or season affect pathogen prevalence.