Scroll down to "Downloads". There is a safety data sheet to download. It doesn't say anything about food-safe certification. However, it does say that you should drink a glass of water after swallowing. The German website of Flashforge only says "Properties of PETG: Food-safe", but also nothing about a certification.

In general, you should not use printed parts for food for a long time, because bacteria or fungi can grow between the layers. But for short term use no problem. PLA and PETG usually have no additives that are not food-safe.
Otherwise you can seal any material with Expxy. But you have to make sure that the epoxy is food-safe.

The PETG from Extrudr is "FDA compliant".