What is the ruling on using a food product containing the additive (E-471), which has both plant and animal sources, given the phrase "permitted stabilizers," and can the principle of "the default state of things is permissibility" be applied?

The basic principle regarding foods is that they are permissible and lawful, and doubt does not render them forbidden. The possibility that the substance might be from pork does not necessitate its prohibition. Rather, the principle of permissibility is applied until that (prohibition) is known, especially since it is produced in Muslim countries.