Dr. Begely: Well, it doesn't infect... This result definitely shows that there are no bacterial spores in the fluid.
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Dr. Shelly: But that doesn't really prove anything. We heated the sample to 90 degrees. At that temperature spores are killed.
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So which is it? Are their bacterial spores or aren't there?

 There aren't any bacterial spores

 There are bacterial spores in the fluid.