I made cream cheese in November and prepared some of my own starter culture from that batch to save money down the line when I wanted to make cheese again. Well, I haven't made cheese since then (now about 4 months later) and I don't know if my starter is still good.
I kept the starter in the freezer since November in ice cubes, and I kept my environment pretty sterile when I made it.
How can I test it to see if it's still good?