Evaluation of the Lactic Acid Fermentation Process for Elimination of Mycobacteria from Wastelage

Open Access
Publisher Website
Google Scholar
Abstract
Nine cultures of mycobacteria and 1 culture each of Salmonella typhimurium and Escherchia coli were placed in formulated rations of bovine manure, poultry litter and corn forage. Rations were ensiled in polyethylene bags at 25.degree. C and survival of the cultures was ascertained. All cultures incubate in bovine manure silage and corn silage rations were eliminated by the 5th day of ensiling, but all survived in the poultry litter silage for 15 days. During ensiling the pH of bovine manure silage decreased from 6.3 to 4.1, that of corn silage from 5.0 to 3.8 and poultry litter silage from 8.2 to 5.5. High buffering capacity of litter silage was responsible for failure of the silage to achieve a low pH similar to other silages. All 9 mycobacteria test cultures grew in lactic acid-acidified Dubos medium at and above pH 4.6, but none grew below pH 4.3. S. typhimurium and E. coli were eliminated from manure-formulated silages when the pH decreased to 4.5 or less; a pH of 4.3 or less was required to eliminate mycobacteria.