YGC agar

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Colonies of Yarrowia lipolytica on YGC agar, the three-field method was used as the smear method.

The YGC Agar (abbreviation of the English name Yeast Extract Glucose Chloramphenicol Agar for yeast extract glucose chloramphenicol agar ) is a nutrient medium for the isolation and selective cultivation of yeasts and molds .

Areas of application

This nutrient medium is recommended by the International Dairy Federation (IDF) and the International Organization for Standardization (ISO) for the determination of the germ content of yeasts and molds in milk and milk products and is therefore also available as yeast extract-glucose-chloramphenicol agar FIL -IDF.

In Germany, the YGC agar in which the German Institute for Standardization issued (DIN) reference method recommended to test for yeasts and molds in milk. The nutrient medium also corresponds to the recommendations of the Food, Consumer Goods and Feed Code according to Section 64 on the Official Collection of Examination Procedures (formerly Section 35 LMBG) and is used in the method for examining food; Determination of the number of yeasts and molds in milk and milk products; Reference method used.

YGC agar is used, for example, to cultivate molds such as Aspergillus brasiliensis (formerly A. niger ), Penicillium species such as Penicillium commune and Geotrichum candidum , as well as for yeasts such as Candida albicans or Saccharomyces cerevisiae . The nutrient medium is particularly suitable for counting yeasts in dairy products with a neutral pH value.

Mode of action

The antibiotic chloramphenicol it contains serves as an inhibitor against bacteria present in the accompanying flora . In contrast to culture media, which have a different antibiotic added for this purpose, the YGC agar can be sterilized in the autoclave without any impairment. A high concentration of the carbohydrate glucose promotes the growth of yeasts and molds, as does the slightly acidic pH value of around 6.6. If not inoculated, the nutrient medium is clear and yellowish. After the inoculation , the nutrient medium is incubated at 25 ° C. for up to five days .

Typical composition

The nutrient medium usually consists of (data in grams per liter ):

Culture media

The following culture media can be used to cultivate yeasts and molds:

Individual evidence

  1. ISO 6611: 2004 (IDF 94: 2004) Milk and milk products - Enumeration of colony-forming units of yeasts and / or molds - Colony-count technique at 25 ° C. In: ISO catalog . October 2004, accessed March 17, 2018 .
  2. a b c d e PDF file: YGC Agar (Yeast Extract Glucose Chloramphenicol Agar FIL-IDF). Merck Millipore , accessed March 17, 2018 .
  3. DIN 10186: 2005-10 Microbiological milk analysis - Determination of the number of yeasts and molds - Reference method. In: Buy norms and standards from Beuth Verlag - a DIN subsidiary . October 2005, accessed March 17, 2018 .
  4. Technical rule BVL L 01.00-37: 1991-12 Analysis of food; Determination of the number of yeasts and molds in milk and milk products; Reference method. December 1991. Retrieved March 17, 2018 .
  5. JJ World Hagen, BC Viljoen: Comparison of th media for the enumeration of yeasts in dairy products. In: Food Research International. Volume 30, Number 3-4, April-May 1997, pp. 207-211, doi : 10.1016 / S0963-9969 (97) 00044-6 .
  6. Michael T. Madigan, John M. Martinko, Jack Parker: Brock Microbiology. German translation edited by Werner Goebel, 1st edition. Spektrum Akademischer Verlag GmbH, Heidelberg / Berlin 2000, ISBN 3-8274-0566-1 , pp. 813-816.