Roast beef query...

So I got this package of deli-cut roast beef from the market a while ago. I open it up, and find something I’ve never seen before: little specks of white stuff all over it. They’re kind of hard, but melt under my fingers when I rub/press it.

Given that, I’m assuming it’s fat (and given that I’ve eaten four sandwiches with this roast beef since then). But how/why did this happen? Does it have something to do with the coldness of the insulated pack I bring my lunch in, or is it something that happened in manufacturing?

(Or, if this isn’t fat, let me know how long I have to live! :D)

Your description sounds like the white stuff is fat. When chilled, melted fat re-solidifies and appears white. Perhaps they didn’t prepare the stuff for packaging correctly. (I’d be more worried about the salt content than the fat content of deli meats.)