Effects of sporulation pH on the heat resistance and the sporulation of Bacillus cereus.
Spores of Bacillus cereus ATCC 7004, 4342 and 9818 were obtained in nutrient agar at several pH from 5.9 to 8.3. The optimum pH for sporulation was around 7, but good production of spores was obtained in the range 6.5-8.3. With all three strains, D-values clearly dropped with sporulation pH, decreasing by about 65% per pH unit. z-Values were not significantly modified (P > 0.05) by this factor. Mean z-values of 7.13 degrees C +/- 0.16 for strain 7004, 7.67 degrees C +/- 0.04 for 4342 and 8.80 degrees C +/- 0.64 for 9818 were obtained.
Mazas
M
M
Departamento de Higiene y Tecnología de los Alimentos, Universidad de León, Spain.
López
M
M
González
I
I
Bernardo
A
A
Martín
R
R
D001409:Bacillus cereus / Q000502:physiology*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D013171:Spores, Bacterial / Q000502:physiology