It is named SF for <em>Streptococcus faecalis.</em>
The genus Streptococcus will be cultured.
Explanation:
A selective media is the one which allows the growth of only certain organism with selective properties to ensure that any other organisms do not grow on the media.
<em>Streptococcus faecalis</em> is a gram-positive cocci which contaminates milk and water through the fecal route as it inhabits the gastrointestinal tracts of several mammals including humans.
The media in which <em>Streptoccous faecalis</em> grows is termed as SF indicating the first letter of the genus and second for the species and being a selective media it can only culture the genus Streptococcus.