Brass nozzles also have trace amounts of lead in them. It's a miniscule amount but if you're going for absolute food safety you may consider a steel nozzle.

You could coat it with a food safe epoxy or clear coat.

It's possible to smoothe PLA by exposing it to ethyl acetate (or get a spool of PVB—prints at about the same settings as PLA and smoothes with isopropyl alcohol). As others have already said though, this is probably not needed for a cutlery storage drawer insert, unless you're in the habit of putting your cutlery away dirty.

There are definitely a few potential options, I think! Mostly experimental ones though, so no guarantees that they actually work lol. For example:

• Sinter it. Basically print at 100% infill, completely pack it in salt/sand/etc, and heat it in a kiln/oven/etc. The plastic will (hopefully) remelt and solidify without all the pockets inside.
• Seal it with something foodsafe and nonpermeable, some kind of varnish or lacquer, even electroplating maybe. The pockets will still be in there but nothing will be able to get into them.
• Use the 3d print for lost PLA casting instead, essentially replacing it with something else like metal.