Any "l" libertarian is against the FDA, as libertarians (of either stripe) believe that the invisible hand of the free market will self-regulate businesses.
The companies that produce subpar and/or contaminated products would go out of business. And sure, some consumers might die in the process, but hey, freedom isn't free!
You're working under the flawed assumption that because something is government regulated, it is safer or better.
That's ideal and all, except for the fact that government agencies are run by people, just like corporations. These government agencies need money to operate, just like corporations. The people at these agencies need to get paid, just like corporations. Not all the people that work at government agencies are of the highest integrity, just like corporations.
It is interesting that a government agency like the FDA allows so much garbage to enter our food supply because it benefits corporations and yet makes it difficult for things that are actually good for us to make its way in...