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P2-122 Effect of Calcium Hydroxide Application to Cattle Feedlot Pens on Escherichia coli O157:H7 and Total E. coli in Pen Surface Manure

Tuesday, August 2, 2016
America's Center - St. Louis
Elaine Berry, U.S. Meat Animal Research Center USDA, Agricultural Research Service, Clay Center, NE
Jim Wells, U.S. Food and Drug Administration-ARS, U.S. Meat Animal Research Center, Clay Center, NE
Terrance Arthur, U.S. Department of Agriculture-ARS, U.S. Meat Animal Research Center, Clay Center, NE
John Schmidt, U.S. Food and Drug Administration-ARS, U.S. Meat Animal Research Center, Clay Center, NE
Mindy Spiehs, U.S. Food and Drug Administration-ARS, U.S. Meat Animal Research Center, Clay Center, NE
Bryan Woodbury, U.S. Food and Drug Administration-ARS, U.S. Meat Animal Research Center, Clay Center, NE
Introduction: Cattle and beef products are sources of the pathogen Escherichia coli O157:H7.  Lime products have a long history of use in cattle production as disinfectants for sick pens, calving pens, and muddy areas, to control the spread of diseases.  Lime may also be useful as a preharvest treatment for reducing cattle exposure and colonization by E. coli O157:H7, thereby reducing risk for beef contamination and human illness.

Purpose: The objective was to determine if hydrated lime (Ca(OH)2) can reduce the levels and persistence of E. coli O157:H7 and total E. coli on feedlot pen surfaces.

Methods: Cattle were removed from 5 feedlot pens.  Four 3 × 6-m plots in each pen were randomly assigned such that one plot of Ca(OH)2 treatment rates of 0, 2.5, 5, and 10% (w/w) was present in each pen.  Ca(OH)2 was incorporated into feedlot surface manure (FSM) using rakes.  Five FSM samples were collected from each plot at 0, 1, 7, 14, 21, and 28 d and analyzed separately (n = 25).  Total E. coli concentrations were determined by direct plating, and E. coli O157:H7 presence was determined by enrichment, immunomagnetic separation, and plating.

Results:   E. coli O157:H7 prevalence in FSM ranged from 0 to 8% from day 0 to day 7, with no difference by treatment (P > 0.05).  E. coli O157:H7 was not detected in any FSM treatment on or after day 14.  Concentrations of total E. coli in FSM were 2.07 and 2.65 log CFU/g lower (P < 0.05) immediately after application of 5 and 10% Ca(OH)2, compared to 0% Ca(OH)2.  However, there was no difference in total E. coli concentrations in any treatment on day 7 or after (P > 0.05).

Significance: Further work is needed to identify Ca(OH)2 levels or alternative lime products to reduce E. coli O157:H7 in cattle and production environments.

Back to: Poster Session 2 – Low-water Activity, Laboratory and Detection Methods, Epidemiology, Produce, Pre-harvest, Dairy and Beverages, Food Defense, General Microbiology
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