Just because it was done in the past doesn't mean it shouldn't, either.
... Not the urine thing. We have better ways to mess with pH.
If you're going to be aging for several years, then sure - sterilizing is useful. Otherwise, you're wasting time with overkill and risking possibly contaminating with bleach or soap flavor.
Menthol's an antiseptic. I'd add it in after fermentation's done.