Lactobacillus starter question

I have a question regarding lactobacillus starters and potential contamination (if that is possible).

Today, on day four of my lacto starter I noticed a rather large furrball resting on the bottom that resembles mold you might find growing on bread, appearing white and fuzzy and about the size of a large marble.

I was planning on pitching into the lacto today but now I’m not sure if I should.

I started by pitching a rather fresh vile of Lacto D. from White Labs into 1000ml of cooled wort (75 degrees) with a gravity of 1.012 (attempting to match the gravity of the beer in the secondary, which currently has a healthy dose of Brettanomyces Brux). I also added 100ml of Santa Cruz brand organic apple juice to the wort prior to pitching to aid in feeding the bacteria.

I purchased a heat pad and played with the settings until I was able to keep the starter around 99-106 degrees and left it in the flask (no stirplate) for 4 days with foil and a rubber band acting as an airlock.

So my question is, did I contaminate it somehow? Should I dump it and start over? Or pitch it and hope for the best?