We make hummus at home a lot and on a few occasions, it seems to have gone bad quickly. It does not turn color or anything, but gets this zippy tangy taste, almost like it's fermenting. I use pretty standard ingerdients each time (chick peas, tahini, s&p, olive oil) and sometimes add extras. This most recent batch had smoked paprika and roasted garlic. It's not left out or anything and is happening after only two days. Anyone know what/why this is happening and how to prevent it?