Description
Oxytetracycline – Glucose – Yeast Extract Agar (OGYE) is based on the formulation of Mossel et. al. and is used in the isolation and enumeration of yeasts and moulds in food samples.1,2
In his early work (1951), Mossel3 reported that Glucose Yeast Extract Agar was comparable to Mycophil Agar which was recommended for use by Sharf (1960)4. Mycophil Agar however supported the growth of Lactobacilli when present because of its acid pH of 5.8.
In later work, Mossel et al5 added Oxytetracycline to the medium as a selective agent and increased the pH to neutral. Koburger et al6 found that the use of this antibiotic in a medium of neutral pH produced higher retrievable counts from a variety of foodstuffs because stressed yeast cells can grow more easily at a neutral or near neutral pH.
It should be noted that due to the possibility of partial decomposition of glucose during the autoclaving process, the pH of the medium may be lowered relative to the level prior to sterilisation. This pH change however, will have little or no effect on the growth of the organisms that the medium is designed to isolate since optimal pH growth conditions for most fungal organisms lies between a pH range of 5.5 – 7.0.
