what types of plastic bags are food safe and big enough for turkey brining?

Suzanne, thanks for the link to food safe plastic bags! I've used a clean, 13-gallon plastic kitchen garbage bag before. There weren't any issues with the plastic affecting the flavor of the food, but I was worried about what might be leaching into the food.

I've also brined a turkey in a big stock pot, but the turkey + the brine + the heavy pot was super heavy for me. We've used the Ziploc XL Big Bags for storage of large items in the past so I know they'll be strong enough and large enough for brining a 20# turkey in. Since it's food grade plastic, I'll feel a lot better about using it instead of a clean garbage bag. Thanks!

I used the turkey roasting bags for my dry brined turkey (15 lb.). I twisted the end real well, fastened the plastic fastener after pressing out the air, and put a twist-tie a couple inches beyond that to ensure no leakage; also taped the whole twisted end flat back on itself with thick packaging tape, but that was probably overkill.

Lori, there was a thread about this right before Thanksgiving. I did the dry brine on my 18 pound turkey (worked great, btw), and I used a clean "kitchen bag." There was some concern that it might not be food-safe, so I ran out in a rain storm in the middle of the night and bought 2.5 gallon ziploc bags which my turkey did not fit into. So I held my breath and kept the turkey in the kitchen bag. We're all still alive so I guess it was OK.

I've preferred to buy a clean plastic bucket (5 or 10 bucks ... It's worth it). Weigh the bird down to ensure the brine covers it. You will end up witha tasty bird, and a new storage container !

Here is a link with some very useful info about food safe plastic bags, has brands and sizes listed, hope this helps.
http://www.virtualweberbullet.com/plastics.html