Smoothing 3D printed object from Polysmooth™ for better cleaning - is it food safe?

Half years ago I created a video where I was talking about food safe 3D printing. One of the test probes was cup 3D printed from Polysmooth™ from Polymaker™. It can be smoothed using isopropyl alcohol. I couldn't find any food grade certificate on the box, but I needed it only to see if smoothing the surface can result easier cleaning after direct contact with food. I smoothed the cup from Polysmooth using a brush, but smoothing was far from perfect and surface become very sticky and it perform very badly on the bacterial test. Few weeks later I was contacted by Polymaker, because my method is not correct, they can provide me PolyBox™ and Polysher™ so I can get more relevant results. They also mention that they have certificate for PVB, the main material in this filament and also for transparent version of the Polysmooth filament. Test was repeated with cups prepared by Polymaker, and they perform much better on bacterial test, but far from perfect, not comparable with Injection Molded or coated with Epoxy resin. Test was prepared in cooperation with University of Novi Sad, Serbia, Department of Biotechnology and Pharmaceutical Engineering.
Contents:
0:00 introduction
6:49 results
7:14 conclusions

Food Safe 3D printing video
https://youtu.be/lFtMIo00tfY
https://youtu.be/lFtMIo00tfY?t=636 (results)

Polysmooth safety data sheet:
https://polymaker.com/Downloads/SDS/PolySmooth_SDS_V4.pdf

University of Novi Sad, Department of Biotechnology and Pharmaceutical Engineering
http://www.tf.uns.ac.rs/site/index.php/en/departments/9-katedre/251-biotechnology-and-pharmaceutical-engineering

Szent István University, Faculty of Food Science
https://food.sziu.hu/node/2830

Cup (STL file) can be downloaded from MyTechFun website:
http://www.mytechfun.com/video/35

Видео Smoothing 3D printed object from Polysmooth™ for better cleaning - is it food safe? канала My Tech Fun