Yeah hummus doesn't last long enough for me to know how long it lasts in the fridge.
I generally don't put tahini in mine most of hte time (although when you do, it definitely adds a richness). I do put lots of garlic in mine. Probably enough that you don't want to be near me after I eat it.
Oh, and I noticed you said you used garlic salt? Ditch that and use WHOLE GARLIC CLOVES. Seriously. There is no way that garlic salt is any kind of substitute for whole cloves. Even if you just use one instead of the 3 I usually use *grin* ... use fresh whole garlic. I promise you that will make a HUGE difference.
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