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Comparative evaluation of four decontamination protocols for the isolation of Mycobacterium avium subsp. paratuberculosis from milk
Author(s) -
Dundee L.,
Grant I.R.,
Ball H.J.,
Rowe M.T.
Publication year - 2001
Publication title -
letters in applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.698
H-Index - 110
eISSN - 1472-765X
pISSN - 0266-8254
DOI - 10.1046/j.1472-765x.2001.00979.x
Subject(s) - paratuberculosis , human decontamination , raw milk , mycobacterium , isolation (microbiology) , microbiology and biotechnology , mycobacterium avium subsp. paratuberculosis , food science , biology , chromatography , chemistry , bacteria , medicine , pathology , genetics
Aims: Four chemical decontamination protocols for milk were compared with respect to mean percentage recovery of spiked Mycobacterium avium subsp. paratuberculosis , minimum detection limit and ease of application. Methods and Results: Raw milk spiked with 10 6 cfu M.a. paratuberculosis was decontaminated prior to culture by: (1) treatment with 0·75% (w/v) hexadecylpyridinium chloride (HPC) for 5 h; (2) and (3) Cornell methods employing brain heart infusion broth containing 0·75% (w/v) and 0·9% (w/v) HPC, respectively; and (4) a C 18 ‐carboxypropylbetaine (CB‐18™) method. The 0·75% HPC method yielded the highest mean percentage recovery of M.a. paratuberculosis (28·7%) and was capable of detecting the lowest number of cells (30 cfu/40 ml). Conclusions: Treatment of milk with 0·75% HPC for 5 h was shown to be superior to the other methods for decontaminating milk prior to culture for M.a. paratuberculosis . Significance and Impact of Study: Certain chemical decontamination protocols are too harsh for application to milk. The ‘best’ decontamination protocol only recovered a fraction of the M.a. paratuberculosis cells present in a milk sample.