You can store Impossible Beef just like any other meat -- it poses no unique food safety risks.
If sold thawed, the package should have a sticker with a “best by" date (added by the store). For best quality and freshness, we recommend keeping it in your fridge and finishing it off before that date. Like any other perishable food, though, after you’ve opened the package, the freshness starts to diminish. After the package has been opened, we recommend finishing it within three days, or by the “best by” date on the sticker -- whichever comes first.
You can re-freeze Impossible Beef to use later if needed. To make sure it stays fresh, we recommend it spend no more than three days total thawed once the package has been opened, and that you finish it off before the "use by" date printed on the back of the packaging.
If you purchase Impossible Beef frozen, you may choose to thaw it in the fridge prior to cooking. Once thawed, it will stay fresh with the package sealed for 14 days, or for three days once the package has been opened -- whichever comes first. The package should be consumed prior to the "use by" date printed on the back of the package.