Bacteria generally turn the media pH indicator yellow/orange, as well as making the media turbid. if you're curious what has contaminated your culture (if anything), just inoculate a bit of your media into LB broth unsupplemented, supplemented with an antibiotic (amp, kan, etc), or supplemented with an anti-micotic (cycloheximide/nystatin) and grow overnight. if nothing grows in your unsupplemented LB then it was not a contamination, if something grows in antibiotic supplemented LB then you know it was fungal, and if something grows in the anti-fungal but not the antibiotic then you know it was bacterial.

However, unless you're continually seeing the same result in your TC culture, contaminations are usually one-off events and it might be quickest to just begin from fresh stocks again as Markus suggested, perhaps being careful of letting the cells culture too long before passage.