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Factors Affecting the Growth and Interaction of the Rough and Smooth Variants of Bacillus stearothermophilus . 2. Media and pH
Author(s) -
HILL W. H.,
FIELDS M. L.
Publication year - 1967
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1967.tb09712.x
Subject(s) - lag time , chemistry , phosphate buffered saline , lag , food science , chromatography , biology , biological system , computer network , computer science
SUMMARY— The influence of various media and pH upon the growth and interaction of rough and smooth variants of Batiks stearothermophilus NCA 1518 in pure and mixed populations was determined. The rough variant had a lower nutritional requirement than the smooth variant. The rough variant had a slightly shorter generation time in a minimal broth than in a trypticase soy broth devoid of phosphate buffer (TSA‐A). The generation time of the smooth variant grown in the minimal medium was much longer than that in TSA‐A. Available carbohydrate influenced growth of the rough variant more than the smooth variant. The rough variant showed an increase of only 3 hr in lag time at pH 6.0 and 8.0 as compared to pH 7.0, while the smooth variant had an increase in lag time of 37 hr at pH 6.0 and 47 hr at pH 8.0 as compared to pH 7.0. The smooth variant produced very little basic substances in TSA‐A while the rough variant produced large amounts of these substances.