HiMedia – M1467 HiCrome™ OGYE Agar Base

Principle and Interpretation
OGYE Agar Media were originally formulated by Mossel et al (1, 2) for the isolation and enumeration of yeasts and moulds from foodstuffs. Mossel et al (3) further added Oxytetracycline as a selective agent and found that the use of Oxytetracycline in a medium with a neutral pH gives increased counts of yeasts and moulds as compared to media having a low pH to suppress bacterial growth. HiCrome™ OGYE Agar is a selective and differential medium, which facilitates rapid isolation of yeasts and moulds from milk and milk products. Yeast extract provides essential growth nutrients. Dextrose acts as carbon and energy source. Although the low pH helps to reduce the bacterial flora, Oxytetracycline makes the medium, more selective by inhibiting the growth of lactobacilli encountered in milk and milk-products at low pH. Incorporation of chromogenic compounds into the growth medium helps in identification of yeasts and moulds isolates directly on primary isolation. *Aspergillus brasiliensis appear as light blue coloured colonies with black spores due to presence of chromogenic mixture, C.albicans shows green coloured colonies and Saccharomyces cerevisiae forms colourless colonies.

原理與解釋
OGYE瓊脂培養基最初由Mossel等人（1,2）配製，用於從食品中分離和計數酵母和黴菌。 Mossel等（3）進一步添加了土黴素作為選擇劑，發現在具有中性pH的培養基中使用土黴素與具有低pH以抑制細菌生長的培養基相比，使酵母和黴菌的計數增加。 HiCrome™OGYE瓊脂是一種選擇性和差異性培養基，有助於從牛奶和奶製品中快速分離酵母和黴菌。 酵母提取物提供必需的生長營養素。葡萄糖充當碳和能源。儘管低pH有助於減少細菌菌群，但是土黴素通過抑制低pH下牛奶和乳製品中遇到的乳酸桿菌的生長而使培養基更具選擇性。將生色化合物摻入生長培養基中有助於在初級分離時直接鑑定酵母和黴菌分離物。 *由於存在顯色混合物，巴西曲霉（Aspergillus brasiliensis）顯示為淺藍色菌落，黑色孢子，C.albicans顯示綠色菌落，釀酒酵母（Saccharomyces cerevisiae）形成無色菌落。