Minimal Growth Temperature, Sodium Chloride Tolerance, pH Sensitivity, and Toxin Production of Marine and Terrestrial Strains of Clostridium botulinum Type C
AUTOR(ES)
Segner, W. P.
RESUMO
Minimal growth temperatures of four marine and two terrestrial strains of Clostridium botulinum type C were determined in a laboratory culture medium, fortified egg meat medium (FEM), and in ground haddock. The inoculum equaled 2 × 106 viable spores per tube with five-tube replicate sets. The spores were preheated in aqueous suspension at 71 C for 15 min prior to inoculation to reduce toxin carry-over. Similar results were obtained in both substrates. Both the marine and the terrestrial strains grew at 15.6 C, but only the terrestrial strains grew at 12.8 C. None of the strains grew at 10 C during prolonged incubation. The sodium chloride tolerance and the pH sensitivity of the marine and the terrestrial strains were determined at 30 C. The basal medium consisted of beef infusion broth. The inoculum level equaled 2 × 106 unheated spores per replicate. Growth was inhibited at salt concentrations from 2.5 to 3.0%. The terrestrial strains were more pH-sensitive than the marine strains. Whereas the terrestrial strains failed to grow below pH 5.62, three of the marine strains grew at pH 5.10, but not at pH 4.96, during extended incubation. One marine strain grew at pH 5.25, but not below. FEM and proteose peptone-Trypticase-yeast extract-glucose medium permitted the production of high levels of botulinum toxin among four media tested. Toxin produced by the marine and terrestrial strains showed no increase in toxicity after incubation with trypsin.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=376479Documentos Relacionados
- Effect of temperature, sodium chloride, and pH on growth of Listeria monocytogenes in cabbage juice.
- Effect of water activity and pH on growth and toxin production by Clostridium botulinum type G.
- Physiology of Toxin Production by Clostridium botulinum Types A and B: III. Effect of pH and Temperature During Incubation on Growth, Autolysis, and Toxin Production
- Heat Resistance of Spores of Marine and Terrestrial Strains of Clostridium botulinum Type C
- Effect of Sodium Chloride and pH on Enterotoxin C Production