Studies on gaseous fermentation of sweetened condensed milk caused by hyperglycophilic torulopsis
Zhang, T.Z.
Zhonghua Yu Fang Yi Xue Za Zhi 21(4): 202-204
1987
ISSN/ISBN: 0253-9624 PMID: 3652868 Document Number: 302861
In 1985, of the 1270 tins of sweetened condensed milk in our district, 600 tins were found bloated. In these bloated tins, no deterioration was evident and the bacteria count also conformed to the standard, but hyperglycophilic Torulopsis (10-2 510/g) was found and, by means of counterevidence, proved to be the bacteria that caused the bloat. The bacteria show little or no growth in malt extract or other non-sugar or low-sugar media, but grew luxuriantly in media with high sugar content. The most suitable concentration of glucose was 40%, at temperature 28-30.degree. C, pH 6 and less than 10% Sodium Chloride. On fermentation with sucrose, glucose, fructose, seminose, raffinose and melibiose both acid and gas were produced, while lactose, maltose, mannitol, D-galactose, inulin, L-arabinose, dulcitol, D-xylose, trehalose and inositol were not fermented. The bacteria were not toxic to the experimental animal. It was identified to be Torulopsis by the Institute of Microbiology of Academia Sinica.