chemically

Biscuits and crackers are chemically leavened.

饼干和脆饼干是用化学方法发酵的。

But honestly there is no way for them to be sure. Until someone invents a way to chemically trace minerals from the source mine, it’s a very difficult problem.

但老实说，这个问题连他们自己也搞不清，除非有人能发明一种化学追踪法，可以将矿产一直追踪到开采地，这的确是个很麻烦的问题。