Isolation and characterization of the microbial population of different South African kefir grains

International Journal of Dairy Technology - Tập 57 Số 1 - Trang 33-37 - 2004
R. Corli Witthuhn1, Tersia Schoeman1, T.J. Britz1
1Department of Food Science, Stellenbosch University, Private Bag XI, Matieland, 7602, South Africa

Tóm tắt

Kefir, a slightly acidic fermented milk, is produced by adding lactic acid bacteria and yeasts, in the form of grains, to milk. The bacteria and yeasts present in the kefir grains are known to vary widely. Selective growth media and morphological and biochemical characteristics were used for the isolation and identification of the microbes present in the grains from eight different sources in South Africa. The kefir grains were activated in milk for only 24 h to prevent any changes in the microbial population of the grains. The microbial numbers varied between 6.4 × 104and 8.5 × 108 cfu/g on the media selective for the bacterial species and between 1.5 × 105and 3.7 × 108 cfu/g on the media selective for the yeast species. The bacterial genera that were identified included Lactobacillus, Leuconostoc and Lactococcus and the yeast genera included Zygosaccharomyces, Candida and Saccharomyces. The distribution frequencies of the microbes in the different grains were determined and most of the grains were dominated by two microbial species. No pediococci, acetic acid bacteria or propionibacteria were detected.

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Tài liệu tham khảo

10.1017/S002202990002759X

Benkerroum N, 1993, Development and use of a selective medium for the isolation of Leuconostoc spp. from vegetables and dairy products, Applied Environmental Microbiology, 59, 607, 10.1128/aem.59.2.607-609.1993

DSMZ, 2001, Deutsche Sammlung von Mikroorganismen und Zelkulturen Gmbh

Duitschaever C L, 1989, What is kefir and how can it be made?, Modern Dairy, 68, 18

10.1006/fstl.1996.0135

Harrigan W F, 1976, Laboratory Methods in Food and Dairy Microbiology, 47

Iwasawa S, 1982, Identification and fermentation character of kefir yeast, Biological Chemistry, 46, 2631

Kaufmann K, 1997, Kefir Rediscovered

Koroleva N S, 1988, Technology of kefir and kumys, Bulletin of the International Dairy Federation, 227, 96

10.1111/j.1365-2672.1984.tb01415.x

Nickels C, 1964, Methode zur differenzierung und quantitaven bestimmung von Saureweckerbakterien, Milchwissenschaft, 19, 374

10.1111/j.1365-2621.1996.16-316.x

10.1111/j.1365-2672.1996.tb03286.x

10.1016/S0723-2020(11)80074-3

Saloff‐Coste C J, 1999, Kefir, Danone World Newsletter, 11, 1

Steinkraus K H, 1996, Handbook of Indigenous Fermented Foods, 305

Swanson K M J, 1992, Compendium of Methods for the Microbiological Examination of Foods, 75

10.1051/lait:19954-523

10.1271/bbb1961.50.2673

Vedamuthu E R, 1982, Economic Microbiology, 199

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International Journal of Dairy Technology

Tập 57 Số 1

33-37

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