In all reality given the conditions in the vial, I would be very suprised if "clear" oil had microbes in it. The reason being, microbes usually produce various compounds that do not react well with oils. Thus if a vial was contaminated it "should" be milky in color. Lets hope for the best.
If the bacteria was able to grow in the oil, then it'd turn turbid, right? If the bacteria is dead when placed in the vial, it won't grow on a plate or liquid culture assessment.
EDIT: Unless it's some sort of spore forming bacteria that can't grow in oil, then it could be clear, no?
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