THE EFFECT OF VARIOUS CARBONATE SOURCES ON THE SURVIVAL OF ESCHERICHIA COLIIN DAIRY CATTLE MANURE

Authors: ARTHURS, C - CORNELL UNIVERSITY; JARVIS, G - CORNELL UNIVERSITY; Russell, James

Submitted to: Current Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/7/2001
Publication Date: 5/7/2001
Citation: ARTHURS, C.E., JARVIS, G.N., RUSSELL, J.B. THE EFFECT OF VARIOUS CARBONATE SOURCES ON THE SURVIVAL OF ESCHERICHIA COLIIN DAIRY CATTLE MANURE. CURRENT MICROBIOLOGY. 2001.

Interpretive Summary: Escherichia coli inhabits the GI intestinal tract of warm blooded mammals, and it can survive for long periods of time in manure. Most E. coli are harmless, but some strains (e.g. E. coli O157:H7) are highly pathogenic. Recent work indicated that E. coli counts decreased rapidly if sodium carbonate and alkali were added to dairy cattle manure, but the mechanism of this antimicrobial activity was not defined. The question then arose, could other forms of carbonate also cause a decrease in E. coli numbers. Results indicated that sodium bicarbonate and sesquicarbonate were not nearly as effective as sodium carbonate, and it appeared that at least 1 mM carbonate anion was needed. The use of carbonate to kill E. coli in cattle manure is an inexpensive method that could decrease human illness due to contaminated water and food supplies.

Technical Abstract: Manure slurries prepared from the feces and urine of lactating dairy cattle (1 part urine, 2.2 parts feces and 6.8 parts distilled water) had an initial pH of 8.6, dissolved carbonate concentrations of 48 mM, and E. coli counts of 5.9 logs per ml slurry. The pH of untreated slurries declined to pH 7.0 by the 10th day of incubation, and the E. coli count increased approximately 10-fold. When slurries were treated with sodium carbonate, potassium carbonate, sodium sesquicarbonate or sodium bicarbonate (0 to 16 g/kg slurry), the dissolved carbonates increased linearly, but only sodium carbonate, potassium carbonate (8 g/kg or greater) or sodium sesquicarbonate (16 g/kg) ensured an alkaline pH. Even relatively low concentrations of sodium carbonate or potassium carbonate (8 or 12 g/kg) caused a decrease in E. coli viability, and E. coli could not be detected if 16 g/kg was added (day 5 or 10 of incubation). Sodium sesquicarbonate also caused a decrease in E. coli viability, but some E. coli (approximately 10 log 4 cells per g) were detected on day 10 even if the concentration was 16 g/kg. Sodium bicarbonate did not prevent the decrease in pH or cause a decrease in E. coli numbers. Calculations based on the Henderson Hassebalch equation (pH and dissolved carbonates) indicated that little E. coli killing was noted until the dissolved carbonate anion concentrations were greater than 1 mM, but bicarbonate anion concentrations as high as 180 mM did not affect E. coli viability. These results are consistent with the idea that carbonate anion has antimicrobial properties and can kill E. coli in dairy cattle manure.