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Sensitivity of Bacillus coagulans spores to combinations of high hydrostatic pressure, heat, acidity and nisin
Author(s) -
Roberts C.M.,
Hoover D.G.
Publication year - 1996
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1996.tb03520.x
Subject(s) - spore , nisin , bacillus coagulans , hydrostatic pressure , chemistry , food science , endospore , agar , d value , microbiology and biotechnology , biology , bacteria , fermentation , physics , genetics , organic chemistry , antimicrobial , thermodynamics
We investigated the combined effects of pressure, temperature, pH, initial spore concentration and the presence of nisin on the survival of spores of Bacillus coagulans. Spores were more sensitive to pressure both at lower pH and at higher treatment temperatures. An additional 1.5‐log 10 reduction in cfu ml ‐1 was observed when pH was lowered from 7.0 to 4.0 during pressurization at 400 Mpa and 45°C. A 4‐log 10 cfu ml ‐1 reduction was observed when the temperature was increased from 25°C to 70°C during pressurization at 400 Mpa. The spores were sensitive to nisin at concentrations as low as 0.2 IU ml ‐1 . At least a 6‐log 10 reduction was generally achieved with pressurization at 400 Mpa in pH 4.0 buffer at 70°C for 30 min when plated in nutrient agar containing 0.8 IU ml ‐1 nisin.