Entirely correct and well backed up with sources. Myself I mix my own e-liquid, whilst not knowing exactly what goes into them due to using flavourings made by flavour companies, I have a better idea than some.
To avoid diacetyl just do not use any eliquid that has a butter like flavour (custards and creams are the usual candidates). When you pick up on what diacetyl smells like you can smell it from a mile off.
Unfortunately though - flavour companies started advertising "diacetyl free" on flavours while replacing it with chemicals which are just as bad - Acetyl Propynol and in some cases Butyric Acid.
Anyone who is interested in this I recommend reading Dr Farsalinos studies on the subject.
To avoid diacetyl just do not use any eliquid that has a butter like flavour (custards and creams are the usual candidates). When you pick up on what diacetyl smells like you can smell it from a mile off.
Unfortunately though - flavour companies started advertising "diacetyl free" on flavours while replacing it with chemicals which are just as bad - Acetyl Propynol and in some cases Butyric Acid.
Anyone who is interested in this I recommend reading Dr Farsalinos studies on the subject.