Abstract
The combined effect of water activity (aw) and pH on growth and toxin production by Clostridium botulinum type G strain 89 was investigated. The minimum aw at which growth and toxin formation occurred was 0.965, for media in which the pH was adjusted with either sodium chloride or sucrose. The minimum pH (at the optimum aw) for growth and toxin production of C. botulinum type G was found to be 5.6. Optimum conditions for toxin activation were a trypsin concentration of 0.1%, a pH of the medium of 6.5, and an incubation for 45 min at 37 degrees C. These data did not show evidence of heat-labile spores, since a heat shock of 75 degrees C for 10 min did not significantly decrease the spore count of strain 89G in media at pH 7.0 or 5.6. It was frequently observed that cells grown at reduced aw or pH experienced severe morphological changes.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Baird-Parker A. C., Freame B. Combined effect of water activity, pH and temperature on the growth of Clostridium botulinum from spore and vegetative cell inocula. J Appl Bacteriol. 1967 Dec;30(3):420–429. doi: 10.1111/j.1365-2672.1967.tb00320.x. [DOI] [PubMed] [Google Scholar]
- Ciccarelli A. S., Whaley D. N., McCroskey L. M., Gimenez D. F., Dowell V. R., Jr, Hatheway C. L. Cultural and physiological characteristics of Clostridium botulinum type G and the susceptibility of certain animals to its toxin. Appl Environ Microbiol. 1977 Dec;34(6):843–848. doi: 10.1128/aem.34.6.843-848.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Giménez D. F., Ciccarelli A. S. Another type of Clostridium botulinum. Zentralbl Bakteriol Orig. 1970;215(2):221–224. [PubMed] [Google Scholar]
- Sonnabend O., Sonnabend W., Heinzle R., Sigrist T., Dirnhofer R., Krech U. Isolation of Clostridium botulinum type G and identification of type G botulinal toxin in humans: report of five sudden unexpected deaths. J Infect Dis. 1981 Jan;143(1):22–27. doi: 10.1093/infdis/143.1.22. [DOI] [PubMed] [Google Scholar]