Premium
Sensitivity of M ycobacterium avium subsp paratuberculosis , E scherichia coli and S almonella enterica serotype T yphimurium to low pH , high organic acids and ensiling
Author(s) -
Cook K.L.,
Flis S.A.,
Ballard C.S.
Publication year - 2013
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/jam.12243
Subject(s) - serotype , salmonella enterica , microbiology and biotechnology , salmonella , mycobacterium avium subsp. paratuberculosis , escherichia coli , paratuberculosis , biology , enterobacteriaceae , mycobacterium , bacteria , gene , genetics , biochemistry
Aims To evaluate the persistence of M ycobacterium avium subsp paratuberculosis ( M yco . paratuberculosis ), S almonella enterica serotype T yphimurium ( S alm . T yphimurium) and a commensal E scherichia coli ( E . coli ) isolate under the low p H and high organic acid ( OA ) conditions of ensiling of forages. Methods and Results Decay rates and the time required to obtain a 90% reduction in cell concentration were calculated following (i) exposure to buffered OA (p H 4·0, 5·0, 6·0 or 7·0) (ii) exposure to silage exudates and (iii) survival through ensiling of forage materials. S alm . T yphimurium had higher decay rates in silage exudates (−0·5601 day −1 ) than did E. coli (−0·1265 day −1 ), but both exhibited lower decay rates in silage than in OA or silage exudates. M yco . paratuberculosis showed no decrease in silage and decay rates in silage exudates were significantly lower (2–12 times) than for the other two organisms. Conclusions E scherichia coli , S alm . T yphimurium and M yco . paratuberculosis exhibit marked differences in response to acidity. All three organisms show acid resistance, but M yco . paratuberculosis in particular, if present in manure and applied to forage grasses, may survive the low pH and high OA of the ensilaging process; silage may therefore be a potential route of infection if ingested by a susceptible animal. Significance and Impact of Study This information contributes to the understanding of potential risks associated with silage preservation and contamination of livestock feed with manure‐borne pathogens.