[quietbritishjim]

> industrially, McD's in at least North America used beef tallow as one of the par-frying oils for their fries well into the 21st century

Everything I've read says that McDonald's switched globally to vegetable oil in the early 1990s. I think you've misremembered.

[bluGill]

Right. They used solid blocks in the 1990s, but it was vegetable oil not beef tallow. Of course to make vegetable oil a solid block they had to make it a trans-far which is worse than saturated fat (as we now know, but didn't then). In the late 1990s they switched to a liquid oil, though I don't know how what it was (I suspect it still had a lot of trans fats, but I don't have information on the composition). I quit just after that, but I think they switched the fat used again in the early 2000s to something that was pure vegetable oil.