Of the three 5L packs that I opened that looked like this, I mixed one. It was definitely darker than the usual ginger-ale color, but moreover the huge quantity and different size of the black particles would have made it very difficult to filter out, so I also have no intention of running my film through this. I returned the three packs yesterday, as Ilford Switz. immediately agreed to exchange them.
I have a fourth pack with the same batch number which looks ok...the crystals in part A are white at least instead of wheat-bran looking, 'though it does have a few black specks.
As I noted before, the 1-liter packs I bought at the same time have no issues whatsoever.
To Simon at Ilford: if it helps in narrowing the origin of the problem, in addition to the 94D098 on the box, the number printed on the Part A sachet was 89A187.