I do what IslandLizard does. I very carefully cut the top of the outer wrapper and pull out the inside pouch of yeast. I spray it with star-san, spray the scissors I'm going to use to cut them. I spray my fingers too.
Then when the time comes to pitch into the flask, I shake up the yeast, spray both yeast and scissors again, cut and pitch.
I've read from White Labs that the possibility of contamination if you don't do this is slight, but why take the chance? I wouldn't worry at all about your yeast.
My son is a microbiologist; I've asked him about this stuff, and you know what? Your starter was almost certainly infected before you even pitched the yeast. All that dust in the air? Lots of it is....contaminated with bacteria, there's wild yeast floating around, it's a miracle we breathe this stuff in and still survive. Some will have made its way into your starter. But it doesn't matter because the billions and billions of yeast cells outcompete whatever gets in there.
BTW, this is why many brewers work to chill fast and get their wort into an enclosed fermenter as quickly as they reasonably can. They'll keep the kettle covered, etc. It's not a panic, it's just that the faster you get the yeast into the fermenter and going, the better.
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I made a starter last night, brewing today. I even go so far as to oxygenate the starter wort so the yeast in there gets a head start, and I try to time my starter so that I'll pitch it 15-18 hours after it begins. And I'll pitch the entire starter into the wort, no chilling, no decanting. I want that yeast going to town when it is introduced to fermenter and its oxygenated wort. I've had action in the fermenter in as little as 3.5 hours after pitching, and always within about 6 hours. I'm working to ensure that whatever fell into the wort before I closed up the fermenter finds itself facing 150 billion or more hungry yeast cells.