Shabbos & Kashrus
A Yid may not instruct a non-Y to perform during Shabbos, the type of work a Yid himself may not perform. However, the non-Y may choose for his own convenience to perform the task during Shabbos.
We may on Friday just prior to Shabbos, instruct a non-Y worker to have a task that takes a few hours to perform, completed by Monday or even Sunday morning. Although it is quite likely and the non-Y may even volunteer, that this work will be ready on Saturday night - as long as there is no instruction implicit or explicit - to perform the task during Shabbos.
Even if Nestle Peters, Keloggs, Cadburry, Sanitarium, Heinz etc. were all fully owned by Yidden, the foods they manufactured during Shabbos would be Kosher. certified or approved, with or without assistance from Kosher agencies [see London Beth Din FAQ and other major K orgs] notwithstanding that their foods are cooked on Shabbos and Yom Tov.
The reason for this is that the foods are not cooked specifically for Jews.
Even those facilities producing foods bearing a paid for, legitimate, Kosher seal, are not prepared specifically for the Kosher consumers.
In Israel the case may be different, but the international and local non-J market is till a significant factor in overall production.