Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: February 13, 2006
Publication Date: July 9, 2006
Citation: Callaway, T.R., Prazak, A.M., Edrington, T.S., Anderson, R.C., Nisbet, D.J. 2006. Isoamyl acetate application as a method to reduce pathogens and methane production in cattle prior to harvest [abstract]. Journal of Animal Science. 89(Suppl. 1):251. Technical Abstract: Cattle can carry foodborne pathogenic bacteria, especially E. coli O157:H7, in their gastrointestinal tracts. These pathogens are spread to consumers through consumption of contaminated meat products, water, fruits or vegetables. The microbial population of the ruminant is inefficient and also produces methane which can waste up to 12% of the Gross Energy of the diet of the animal. If a method to reduce pathogens also increases the efficiency of the fermentation then the economics of improving food safety can be enhanced. Isoamyl acetate (IA; banana oil) is a naturally occurring aliphatic carboxylic ester widely used as a flavoring agent in foods that has been reported to have bacteriacidal activity. In the present study we added IA at various concentrations (from 0 to 50 mM) to pure cultures of E. coli O157:H7 (initial concentration of 10^6 CFU/ml) and found that approximately 30 mM IA demonstrated significant (P < 0.05) antibacterial activity. Mixed ruminal contents from grass-fed Holstein cows was used for in vitro mixed culture studies. Ruminal fluid (containing 1 g/L glucose and xylose) was inoculated with 10^4 CFU/ml E. coli O157:H7 and added to separate anaerobic tubes (n=16). IA was added to achieve final concentrations from 0 to 50 mM in each tube. Tubes were incubated at 39 C for 24 h. Samples were serially diluted (10-fold increments) and plated to determine populations of inoculated E. coli O157:H7. E. coli O157:H7 populations were reduced (P < 0.05) in tubes containing >30 mM IA. Parallel tubes (n=16) were incubated to determine the effects of IA on the ruminal fermentation. Total gas volume, CH4, and total VFA concentrations were reduced (P < 0.05) in tubes containing >30 mM IA. Results suggest that IA could be used as a surface or hide disinfectant with more efficacy than as a feed additive because the impact on the overall fermentation efficiency appears to be detrimental.