There is bacteria in there. Whether or not it will cause a problem is hard to say. A major risk of pitching a potentially contaminated starter, one that may not smell/look bad at first, is the bacteria will have a chance to outgrow the yeast once pitched into fresh wort.
If your starter looks/smells/tastes bad, it is obviously a no-go. If it doesn't, you decide if you will risk it or not. I always default to pitching the best yeast possible. If you are going to the trouble of making 5 gallons of delicious wort, why risk ruining everything with your pitch.
To be very general though, it is probably fine. There is probably enough yeast, and probably very few bacteria, and it will probably make fine beer. But, I like the details, and it is ususally the difference between good beer and great beer.
Bacteria are the only culture some people have.