The Minimum Temperatures of Growth of Some Bacteria

The commonly occurring bacteria may be divided into four groups on the basis of their behaviour at various temperatures. These are (i) the Staphylococci, not growing below 10° C, (ii) most strains ofB. coli, B. proteusand Micrococci ceasing growth in the range 5−0° C, (iii) some strains ofB. proteusetc. capable of growth at 0° C, (iv) many strains ofAchromobacter, Pseudo monas, and various yeasts growing rapidly at 0° C. (sometimes in 5 days), and down to about −5° C. on unfrozen media. 2. Bacterial growth on frozen media has not been observed below −3° C. The author is indebted to Dr G. S. Graham-Smith, F.R.S., who read the manuscript, to Mr W. A. Bmpey for the supply of cultures, and to Mr J. Barlow for assistance in the experimental work.