"Food safe" is a certification that in order to get you have to have your stuff comply with a number of points and then apply to the FDA to get. So chances are there will never be a "food safe" 3d print.

However in order for a print to be food safe compliant it would probably need to be:
1. Printed in a plastic that doesn't degrade to dangerous material. ABS is out, PLA or PET is in.
2. Printed in a plastic that won't warp in a hot dishwasher. So now PLA is out too.
3. Not extruded through a brass hot end because brass contains lead. Steel only.
4. Smoothed so that there are no 3d printed layers where bacteria can grow.

Of course keep in mind not being food safe does not mean if you use it you will automatically get sick. It just means there's a higher risk of contamination. Is that risk too high for you? Maybe not. Chances are a 3d printed bread knife will work just fine. It's up to you. Personally I'm not bothered by it.