• Journal of Environmental Health Sciences
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• v.7 no.1
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• pp.51-57
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• 1981

This Study was carried out to investigate yeast and mold contamination in fermented milk products produced by 9 different domestic manufacturers from October 20. to December 5. 1980 The results obtained in the study were as follows 1) pH values of the products were ranged from pH 3.14 to pH 4.20 and average of sour milk drinks was pH $3.66\pm 0.19$ and fermented milks pH $3.74\pm 0.11$. Therefore the difference of pH average among sour milk drinks and fermented milks was statistically significant. (p<0.01) 2) In case of yeast contamination, yeast was found on all the four producted at the same date. From this result, it seemed that yeast contamination occured during the manufacturing progress. 3) Degree of contamination by the indicator organisms was E. coli positive, 3.7%: over 1,000 yeasts/ml, 14.8% over 10 molds/ml, 0.9%. 4) In the range of over 1,000 yeasts/ml, degree of contamination by yeast was 8.4% in fermented milk and 16.7% in sour milk drink. 5) Yeasts in product C increased to the spoilage number within 5 days and in H increased within 10 days at 5C. At 15$\circ$C, yeast increased to the spoilage number within 15 days in product A.D. 6) It seems that the yeast number of initial contamination should be important than the increase rate as criteria on the fermented Milk products.

• Mycobiology
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• v.38 no.3
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• pp.206-209
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• 2010

To produce bioactive compound enriched yeast using medicinal Gugiga (Lycium chinensis Mill), several edible Saccharomyces species were cultured in Gugija extracts added yeast extract, peptone and dextrose medium (GE - YEPD medium) at $30^{\circ}C$ for 24 hr, and their growth were determined. Growth of Saccharomyces cerevisiae K-7 and Sacchromyces cerevisiae ACTC 7904 were better than those of the other yeasts. Two yeasts were selected and then determined their some physiological functionalities after cultivated the yeasts in the GE - YEPD medium and compared those grown on YEPD medium. Antihypertensive angiotensin I-converting enzyme (ACE) inhibitory activity of S. cerevisiae K-7 grown on GE - YEPD medium was about 20% higher than that grown on YEPD medium. Superoxide dismutase-like activity of S. cerevisiae ACTC 7904 was also about 12% more high. However, the other physiological functionalities were almost same or lower. Optimal addition concentration of Gugija extract was 10%, and maximally growth and ACE inhibitory activity of S. cerevisiae K-7 were shown when the strain was cultured in 10% Gugija extracts containing YEPD medium at $30^{\circ}C$ for 12 hr.

• Mycobiology
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• v.39 no.1
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• pp.33-39
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• 2011

Wild yeasts on the surface of various fruits including grapes were surveyed to obtain yeast strains suitable for fermenting a novel wine with higher alcohol content and supplemented with rice starch. We considered selected characteristics, such as tolerance to alcohol and osmotic pressure, capability of utilizing maltose, and starch hydrolysis. Among 637 putative yeast isolates, 115 strains exhibiting better growth in yeast-peptone-dextrose broth containing 30% dextrose, 7% alcohol, or 2% maltose were selected, as well as five ${\alpha}$-amylase producers. Nucleotide sequence analysis of the 26S rDNA gene classified the strains into 13 species belonging to five genera; Pichia anomala was the most prevalent (41.7%), followed by Wickerhamomyces anomalus (19.2%), P. guilliermondii (15%), Candida spp. (5.8%), Kodamaea ohmeri (2.5%), and Metschnikowia spp. (2.5%). All of the ${\alpha}$-amylase producers were Aureobasidium pullulans. Only one isolate (NK28) was identified as Saccharomyces cerevisiae. NK28 had all of the desired properties for the purpose of this study, except ${\alpha}$-amylase production, and fermented alcohol better than commercial wine yeasts.

• Tuberculosis and Respiratory Diseases
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• v.38 no.3
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• pp.287-296
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• 1991

Colonial morphology of the various yeasts often encountered in sputum or other clinical specimens was investigated on the corn meal-potato-yeast extract agar medium (GJCPY) containing orange-yellow pigments extracted from Gardenia jasminoides fruits in hopes of differential identification on primary cultures. The results obtained are as follows. 1) Cryptococcus neoformans which is a medically important yeast and whose colony showed brown to purple brown on GJCPY medium was distinguishable not only from buff colored Cr. laurentii after one week incubation but also from Candida spp. 2) Colony color of Candida albicans, a most common species in sputum specimens and of Ca. parapsilosis, a rare isolate, remained unchanged even after 15 days incubation. 3) Ca. tropicalis, second common isolate from sputums and Ca. krusei, a rare isolate, formed a characteristic rough and wrinkled colonies that permit to differentiate them from others. 4) Rare isolates, Ca. guilliermondii and Ca. lusitaniae, turned to prussian blue within three days of incubation. 5) Torulopsis sp. and Saccharomyces cerevisiae showed glossy grayish blue or light blue after one week incubation. The findings clearly showed that Ga. jasminoides pigments medium was useful to the morphological differentiation of medically important yeasts that were often encountered in sputum or other clinical specimens.

• Korean journal of food and cookery science
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• v.4 no.1
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• pp.41-46
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• 1988

Omija tea with a pH range of 2.8~3.0 was stored at $25^{\circ}C$ to study its spoilage due to microbial growth. Titratable acidity was increasing during the storage period in the tea stored with the Omija fruits but not in removed of the fruits after extraction. Microbial cells began to show up earlier in the tea without the fruits than that with the fruits. Four strains of yeasts and a strain of mold were isolated from spoiled Omija tea. Morphological, cultural and physiological characteristics of yeasts were investigated and the yeasts were identified as Rhodotorula rubra, Saccharomyces kluyveri, Cryptococcus hungaricus and Candida humicola. Morphological characteristics of the isolated mold was observed and the mold was identified as Mucor circinelloides f. janssenii.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.1
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• pp.126-130
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• 2006

The purpose of this research was to study the effect of freeze drying on the microorganisms in kefir. Influences of lyoprotectants and rehydrated media (water at $4^{\circ}C$, $25^{\circ}C$; 10% reconstituted milk at $4^{\circ}C$, $25^{\circ}C$) on the viability of lactic acid bacteria and yeasts in freeze-dried kefir were investigated. Kefir was made from cow milk which was inoculated with 5% kefir grains, and incubated at $20^{\circ}C$ for 20 h. Lyoprotectants (galactose, lactose, maltose, sucrose and trehalose) were added independently before dehydration of kefir by freeze drying. Results indicated significant loss in viability of microorganisms in kefir after freeze-drying. Addition of 10% galactose or 10% sucrose as lyoprotectants significantly increased the survival rates of both lactic acid bacteria and yeasts (p<0.05). The $4^{\circ}C$ rehydration temperature showed the best viabilities for yeasts, however, viability was not significantly affected by rehydration media (p>0.05).

• The Korean Journal of Mycology
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• v.40 no.3
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• pp.174-176
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• 2012

We report morphological and physiological characteristics of newly isolated six kinds of yeasts which are new in Korean mycoflora. The yeasts were isolated from wild flowers in Daejeon city, Korea and identified by molecular analysis of the amplified internal transcribed space rDNA sequence or partial 18S rDNA sequence. Species of isolates were identified as Kuraishia capsulate, Lodderomyces elongisporus, Pseudozyma antarctica, Starmerella bombicola.

• The Korean Journal of Mycology
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• v.39 no.3
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• pp.229-230
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• 2011

Growth profiles of Candida krusei KCTC 7213, Torulopsis sphaerica KCTC 7138 and Zygosaccharomyces rouxii KCCM 12066 in pear marc extract were determined. Candida krusei KCTC 7213 showed the highest growth in 20 hr cultivation at $30^{\circ}C$, whereas both of Torulopsis sphaerica KCTC 7138 and Zygosaccharomyces rouxii KCCM 12066 established maximal growth by 25 hr of cultivation at $30^{\circ}C$ in pear marc extract. However, all of yeasts showed lower growth in pear marc extracts rather than those of YEPD medium.

• Korean Journal of Food Science and Technology
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• v.19 no.5
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• pp.453-455
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• 1987

Swollen commercially canned grapes and peaches were collected to investigate the microorganisms involved in their spoilage. 6 of 52 grape and 19 of 23 peach samples were found to be spoiled by microorganisms. Yeasts were the only spoilage microorganisms of canned grapes with Saccharomyces cerevisiae as the leading spoilage yeast. Yeasts and bacteria were found from spoiled canned peaches. S. cerevisiae and Torulopsis stellata were the most important spoilage yeasts of canned peaches. Lactic acid bacteria, belonging to genera of Lactobacillus and Leuconostoc, were the most frequently found spoilage bacteria. Only one spore-forming bacterium, Bacillus licheniformis, was involved in the spoilage of canned peaches.

• Journal of Microbiology and Biotechnology
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• v.17 no.2
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• pp.297-304
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• 2007

The effect of yeast propagated at different aeration conditions on yeast physiology, fermentation ability, and beer quality was investigated using three strains of Saccharomyces cerevisiae. It was shown that yeast cells grown under continuous aeration conditions during propagation were almost two times higher as compared with discontinuous aeration conditions. The maximum of cell growth of all samples reached between 36 hand 48 h. The concentration of trehalose was increased under continuous aerated yeasts, whereas glycogen was decreased. It was also observed that the concentration of glycogen and trehalose in yeast cells had no direct effect on subsequent fermentation ability. The effect of yeast propagated under different aeration conditions on subsequent fermentation ability was different from yeast strains, in which the influence will be most pronounced at the first fermentation. Later, the yeasts might regain its original characteristics in the following fermentations. Generally, continuously propagated yeast had a positive effect on beer quality in subsequent fermentation. Hence, the concentration of aroma compounds obtained with yeast propagated under 6 1/h for 48 h aeration was lower than those grown under other aeration conditions in the bottom yeasts; in particular, the amounts of phenylethyl alcohol, ester, and fatty acids were decreased.