Heat the milk, slowly, to 86°F on the lowest possible setting.
Remove the milk from the heat and stir in the packet of cream cheese culture mixture with an up and down motion, not round and round. [Do not stir longer than 15 seconds.]
Cover the pot and leave the mixture to culture at room temperature for 12 hours (about 72° - 77°F.)
After 12 hours, your milk will curdle. Remove the lid and you’ll see the cheese is fairly solid but still relatively soft and resembles yogurt. This is normal and is what makes milk become cream cheese. The whey (clear or cloudy liquid) is separating from the cheese. (Save the whey for other uses if you like. *see below)
Next, drape a piece of doubled muslin in the colander set over a bowl. (I clip the edges of muslin to the bowl to hold it in place.) Carefully pour or spoon the cultured milk into the prepared container.
Gather up the corners of the muslin, use cotton string to tie these together, then hang from a hook or knob, allowing the whey to drip into a clean large bowl (you can use the leftover whey, too!)
After 6-12 hours, the cream cheese will reach a thicker consistency. (The longer you allow it to drain the more it will thicken.)
Salt the cream cheese and store in an airtight container.