Metabiotic growth of clostridium botulinum with toxin production in the fresh tomato

The fungi Alternaria, Aureobasidium, Fusarium, Geotrichum, Mucor, Fusoma, Rhizoctonia, and Stemphilium were identified in molded tomatoes obtained in local markets. The pH of the infected tissue of tomatoes grown in Arizona was as high as 7.4, and of tomatoes grown in California as high as 8.3. The pH of the sound tissues of the center of some tomatoes and of the tissue across from the site of infection was raised as compared with the pH of normal tomato tissue. Bacillus megaterium, B. Thuringensis, Enterobacter hafnia, Erwinia (6 species), Klebsiella pneumoniae and Staphylococcus were recovered from the juice cavities at the site of infection from 21 of 28 tomatoes examined, from the center of the tomato of 6 and across from the site of infection from 11 tomatoes. Mesocarps of sound, early mature tomatoes exposed by folding back incised skin were inoculated with Alternaria, Rhizoctonia, or Fusarium and with one loop heated cell suspension of either Clostridium sporogenes or C. Botulinum. The tomatoes were incubated at 25°C and 30°C for three or more days. Visible deterioration was observed only at the site of infection. C. Sporogenes was isolated from the juice cavities of 15 of 18 tomatoes adjacent the mesocarp, from tissue of 9 of 18 tomatoes 1 cm distant from the site of infection and from 4 tomatoes at the site across from the The pH of the infected tissue ranged from 6.39 to 8.0. The pH of tissue 1 cm distant from the site of infection was between 4.36 and 4.9, and of tissue across from the site of infection between 4.3 and 4.46. C. Botulinum was recovered from 19 of 27 juice cavities inoculation. adjacent the site of infection, from 6 of 26 tomatoes at a distance of 1 cm and from 1 of 21 tomatoes at the far side.

With an inoculum of 4 X 10³ spores, the estimated numbers of cells of C. Botulinum in infected tissue ranged from 2.4 X 10⁶/g macerate of the fifth day when inoculated with Alternaria, to a maximum of 9 X 10⁹ cells/g macerate when the tomato was inoculated with C. Botulinum 4 days after inoculation with Fusarium. Toxic effects of the infected tissue were demonstrated by the injection of 0.09 ml of tissue supernatant diluted to 0.35 ml in gelatin-phosphate buffer into mice. Twelve of 16 mice receiving supernatants from tomatoes with associated growth of the molds Alternaria and Fusarium died, but only 1 of 8 mice died when Rhizoctonia was the associated mold. Three of 8 mice receiving heat-inactivated supernatant of Alternaria-C. Botulinum died, and all injected with Fusarium-C. Botulinum heated-inactivated supernatant survived. Mice given toxic supernatant and antitoxin survived.