Choosing the right material for what you are printing requires some research - ultimately the decision of which material to use depends on what you use it for.
Food safe and non-food safe 3D printing filaments (FDA Approved);
Safe 3D printing materials for food contact:
PLA without additives - Natural PLA is made from corn starch and is generally considered food safe, however it has a low melting point, an aspect definitely to be considered when heating and storing food. It is always wise to check with your suppliers as some manufacturers will blend in other additives for color or strength which can make the filament unsafe to ingest.
PET, PETG / T-Glass (Ultra-transparent modified PETG). Used for bottled water among other things.
ULTEM 9085, used to make food trays.
Polypropylene (PP), one of the most common food storage plastics.
Natural grade Nylon 6 & 6.6 (without additives)
Ways to ensure your prints are food safe;
Wash your part with warm water and antibacterial soap immediately after use
don't use the dishwasher - prints become deformed and warped with time leaving space for bacteria to grow
Seal your print with a food safe epoxy or sealant to cover the porous areas that may collect bacteria.
Unsafe 3D printing materials for food contact;
ABS - ABS filament is generally considered unsafe to use with anything that will come into contact with food, it contains toxic chemicals which can contaminate your food.
PLA with additives (Do adequate research on the filament you choose to use)
Nylons with additives (e.g. oilon or Mos2)
*** Always check the material safety data sheet (MSDS) that breaks down the chemical properties of the filament and will specify whether it is FDA approved or food safe***