Hi,
While I'm unsure about the particulars of Food Saver bags, I can tell you that many, MANY plastic bags that you'll find at grocery stores contain PVCs and other agents harmful to coins. I highly recommend buying the right coin storage containers for your coins to ensure they won't get ruined over the long haul. These safe coin supplies include inert 2x2 flips, inert plastic tubes, and quality coin folders and coin albums. While they may cost a little more than the plastic bags at the grocery store (or mean having to wait a few days to buy them at your local hobby supply store or via the internet) -- trust me! -- it's an investment that will pay you dividends over the long-term.
Best wishes!
Josh @ CoinValues