What is the ruling on eating cheese made from calf rennet imported from Western countries?

Cheese mixed with rennet from a ritually slaughtered calf is unanimously considered permissible (halal). However, if it's mixed with rennet from a calf not ritually slaughtered, there is a difference of opinion: some permit it because the Companions ate cheese made by the Majus (Zoroastrians), which was mixed with rennet from their dead animals, and because impurity can become pure through transformation (istihala). Others forbid it, arguing that what separates from a dead animal is also considered dead (maytah). It is advisable to err on the side of caution and avoid areas of disagreement as much as possible, or to take only what is necessary when there is a need. As for rennet taken directly from a living animal (as a liquid), it is unanimously considered pure because it is not something severed from a living being; rather, it is in the same category as the vomit of an edible animal.