Description
WL nutrient media is prepared to the formula described by Green and Gray, who pursued an extensive study of brewing and industrial fermentation processes and techniques used to monitor microbial contamination.
Their work on various beers, worts, liquid yeasts and other fermentation products led to the production of a basic formula, which could be produced in agar or broth form, adjusted in pH to suit various requirements and be rendered selective for bacteria but inhibitory to yeasts, when examining the bacterial flora usually encountered in beers. Variations in incubation atmosphere, time and temperature are also possible with these media, so that the whole spectrum of bacterial and yeast flora associated with fermentation processes can be adequately controlled with their use.
WL Nutrient media is suitable for the growth of yeast, but where the yeast cell numbers are low, bacteria may also be detected. pH 5.5 is suitable for the cultivation of brewer’s yeasts but adjustment to pH 6.5 with 1% sodium bicarbonate facilitates the growth of baker’s and distiller’s yeasts
