What sealants and plastics are safe to use?

Given that there’s a bit of plumbing and waterworks, how do I know I’m using components that are safe to use in a machine that will eventually feed me?

For example, milliput. Can I safely use it in an area that comes in contact with the water, soil or plants?

Is foodsafe plastic the same as farmbotsafe? This site here has a nice list: