I'm getting sick of seeing "preservative-free" emblazoned on every cosmetic package I come across. Maybe it was the microbiology classes in college, but frankly, I'm quite fond of preservatives. What exactly is the FDA's stance on preservatives in cosmetics? Are they optional? Required, but loosely enforced?

I recently looked at the ingredients on a mass market mineral foundation that contained organic (in the chemical sense, not the agricultural) fillers but had no preservatives. I know the chance of contamination in a "pure" mineral foundation (i.e., only crushed minerals sans fillers or additives) is relatively low since a bunch of dry inorganic powder isn't the most hospitable environment for microorganisms. But wouldn't the risk be increased by using tasty additives like Aloe barbadensis gel? The liquid formula from the same line had a similar LOI, but with methylparaben. Is there a reason besides marketing to omit preservatives in the powder? Am I just worrying too much?