Ps. Fernandez et al., RELATION BETWEEN THERMAL-RESISTANCE AND DPA CONTENT IN VARIANTS OF THE SAME STRAINS OF BACILLUS-STEAROTHERMOPHILUS SPORES, Letters in applied microbiology, 19(2), 1994, pp. 118-120
Rough and smooth variants of Bacillus stearothermophilus strains ATCC
12976 and 12980 were isolated. These variants showed morphologically d
ifferent colonies. In both strains the rough variants were less heat-r
esistant than the smooth ones, and their activation occurred in a shor
ter time; on the other hand, their dipicolinic acid (DPA) content was
higher. These results indicate that a relationship between higher DPA
content and higher thermal resistance does not exist. Therefore, this
evidence supports the hypothesis that DPA is not the determining facto
r in the degree of spore heat resistance but that it could, instead, h
ave a role in maintaining thermal resistance obtained by other means.