1978 Volume 19 Issue 3 Pages 273-281_1
To evaluate the safety of biological and chemical contents in “Tea fungus” as a kind of soft drink, microbial flora and organic acid content in this drink were investigated.
As the result of microbial investigation, Acetobacter xylinum was isolated from the drink as sole source of bacteria and other yeasts such as Saccharomyces cerevisiae, S. inconspicus, Candida tropicalis, Debaryomyces hansenii, were also found. Among those isolates tested, A. xylinum was found to be a zoogloeal mats forming organism, and the product was increased in cooperation with S. cerevisiae.
As the result of organic acid analysis by gas liquid chromatography, acetic acid, formic acid and lactic acid were found, especially acetic acid content occupied more than 95% of the total of them in this drink.
Several kinds of pathogenic bacteria such as Salmonella typhi, Shigella sonnei, pathogenic Escherichia coli, Staphylococcus aureus, were all died within 24 hours, when experimentally inoculated into the drink and incubation at both of 25°C and 37°C, though several kinds of filamentous fungi were found grow well in it.