The objective was to develop a practical method to control E. coli O157:H7 in drinking water for cattle and reduce the likelihood of transmission of E. coli O157:H7 through drinking water in the trough on the farm.
Depending on initial cell numbers present, E. coli O157:H7 can survive at room temperature (21°C) in water contaminated with rumen content for more than one year. The killing effect of 5 ppm chlorine and 22-24 ppm ozone was neutralized by the addition of rumen content at 100 parts water to 1 part or more of rumen content. Three chemical combinations, including: (A) 0.1% lactic acid, 0.9% acidic calcium sulfate and 0.05% caprylic acid; (B) 0.1% lactic acid, 0.9% acidic calcium sulfate and 0.1% sodium benzoate; and (C) 0.1% lactic acid, 0.9% acidic calcium sulfate and 0.5% butyric acid were highly effective at 21°C in reducing large cell numbers (105 cfu/ml) of E. coli O157:H7, O26:H11 and O111:NM to undetectable levels (by enrichment) within 30 minutes in water heavily contaminated with rumen content at a ratio of 10:1(water:rumen content) or feces at a ratio of 20:1 (water:feces).
Water for cattle contaminated with rumen or fecal matter will need alternative methods to control the transmission of E. coli O157:H7. The results from this study demonstrated 3 treatment combinations that would be effective in reducing E. coli O157:H7, O26:H11 and O111:NM to undetectable levels.