In a large, heavy pot, heat milk over medium-high heat just to the point of boiling, stirring often to prevent scorching. As soon as it looks as though it's about to boil (small bubbles are beginning to break the surface), remove from heat and drizzle in lemon juice, whisking briskly. Reduce heat to low, return pot to burner, and whisk for another 2 minutes (do not let boil). Cover and let sit 10 minutes.
Meanwhile, line a large colander with cheesecloth and set in sink. Pour in curds and whey. Tie two opposite corners of cheesecloth into a knot over curds and repeat with other two corners. Hang cheesecloth sack from sink faucet for 1 to 2 hours, or until curds have stopped draining.
Pour curds into a bowl and add salt and oregano. Rub between your fingers to mix and to break curds into small grains. Cheese will keep, covered and chilled, up to 1 week.
Note: Nutritional analysis is per tablespoon.