Strange dust in the Nikon 85mm/1.8 lens

Last Saturday I bought a Nikon 85mm/1.8 lens to use for portraits and for general photography. A strange thing happened though — after trying out the lens for a few minutes, I became aware of a small dust particle on the inside of the glass! It actually looked like a black piece of plastic had been dislodged from the barrel somehow and ended up on the lens.

These things happen I guess, so I returned it and got another one. At home, I once again unpacked it and inspected it thoroughly as usual. Lo and behold, this lens had the same problem as the other one — dust inside the glass! They had no more 85mm lenses in stock either, but I am glad for the refund.

It looks like I am not supposed to have a fast 85 mm lens, but I am looking for alternatives.