Just naturally cautious, I won’t even drink out of a plastic water bottle either if I’ve left it in the car any amount of time.
Have done a 48 hr cook—just prefer to do cooking in bags meant for sous vide-
I do use ziploc bags too
@saluki always better to be safe! 
ZipLoc bags are great to use as well: Ziploc® | Sustainability & Safety | Ziploc® brand | SC Johnson
@tkyogastronome:
I think you might have overcooked your steaks. Here, below, are Kenji Alt’s recommendations for steaks. I prefer Med-rare, and I NEVER cook my steaks more than 1 - 1 1/2 hours. Thick loin lamb chops cooked this way were spectacular!
Beef Steak Med 140°F 45 min - 3 hours
Beef Steak Med-rare 130°F 45 min - 3 hours
Beef Steak Med-well 150°F 45 min - 3 hours
Could be more going on with the steaks… There is a previous discussion under the heading Bland and Dry:
Soft boiled eggs… 167 degrees for 13 min. Make sure temperature is exact. If they are not done enough for you try bumping up your time by a minute until you get it right.
If your meat is coming out dry, try salting or brining it, before you seal it in vacuum bags.Let the bags sit, in the refrigerator, for a day or two, before cooking them. You can also make sure, that you don’t set the temperature too high. Seriouseats.com has some good advice, on temperatures.