Moldy Beer?

I'm trying to keg a batch of porter after 5.5 weeks of fermenting and after opening the fermenter, I noticed some spots on the top of the beer that look like mold. The color of it is greenish. I'm just wondering if this is actually mold, should I keep it or will it be affected? Here is a picture of the batch.

Can't tell from the photo, but it's likely just yeast rafts.

Unless you're seeing hairs growing, or it smells/tastes like Satan's Anus, bottle it and drink it.

Ok good but the batch still has the same flavor as the two previous ones did. A sour odor and smell which completely ruined the 2nd and slightly mellowed out over the life of the first.

Its not the water and I have a hard time believing we have ruined 3 out of 3 batches after being so careful. I don't think its the aluminum pot because the smell and taste is so strong.

Could it be the yeast? We usually buy the cheapest yeast we can. Is yeast making my beer sour?

Sour or astringent (Vinegar or Red Wine)

If you're fermenting WAY too hot, it may create some flavors that can seem kind of astringent, the same can happen if you're boiling your steeping grains.

A sour taste, on the other hand almost always means that you've got a infection of some kind (and it will be bacterial or wild yeast, which your photo does not look like.)

What source are you using for your yeast? The cheapest brewers yeast I can think of off the top of my head are Nottingham or Windsor, which should both ferment out reasonably clean (if a bit sweet in the case of Windsor.)