update: as I imagined, in speaking with Medela, they can not give a clear answer, but do err on the side of caution and recommend dumping the last 1-2 days worth of milk, given the speed of spore growth.  I was skeptical about the earlier reference I found :)  For future reference for others, they also send new tubing to moms that are experiencing mold growth in their tubing.   Thanks!

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