Foundation 粉底

With the exception of powder formulas, all foundations are water-based, which means bacteria love them. Unopened, foundation can last for a couple of years, but once the seal is broken, Hammer says, it's best to replace it after 6 to 12 months. Keep foundations out of moist environments (such as your bathroom) and away from heat, as high temperatures encourage the growth of the bugs and can speed up the spoiling—true for beauty products in general. An off smell or a change in color tells you the formula is finished—applying it could cause irritation or breakouts。

Tips：粉底都含水，所以易滋生细菌。没开封的粉底可保质几年时间，一旦拆封，6到12个月就该换了。变味和变色是粉底变质的征兆。