Open bottle of Whole Foods cider- need to pasteurize again??

Hi there!

Sorry if this is a silly question, but I'm a total newb! I bought two 1 gallon jugs of 365 juice to ferment, an s-04 yeast, airlocks and toppers, but have been researching whether I want to buy more equipment like to check SG, tubing and bottles, sanitizer etc. before I pitched the yeast. (Yes to all of those!)

Anyway, I had to open one of the bottles to check what size top I needed, and forgot that I had opened it and it has been sitting out with the other jug at room temperature for almost a week now! Uh Oh.

I was planning on adding brown sugar and apple juice concentrate before starting the brew, should I just put the juice in a pot, warm it to 170 to pasteurize it again, and dissolve the sugars in it? Do I need to sanitize the pot first? Do I need to sanitize the jug after I pour out the juice? TIA!!

First pour out like 2 oz or so to smell and taste. If it tastes ok, doesn't smell then you are probably fine to toss yeast in on it. But for peice of mind and all do one of the 2 options below.

Option 1 : get some campden tablets or metabisulfate and put that in wait 24 hours and go from there.

Option 2: use a 'double boiler' method and pasturize the juice in the glass jug. Just put the whole thing in a large pot that has water in it. This will allow you to take care of all that sanitation in one shot.

Option 3, pasturize the juice in a pot, and sanatize the jug with Idophor or Star San when you sanatize everything else.

I'd cap it with an airlock and wait a bit. If it's bubbling, wild yeast is already going and I'd just let it go.

Personally, I would just add a bit more yeast (even if wild stuff is going) and see what happens. Little to lose

Oh, I like the double boiler method- esp. as I don't have my sanitizer yet. Thanks so much for the input!

**update** I tasted it and it seemed fine. I just added some brown sugar and sprinkled the yeast on top. I figure I can take a risk with 1 gallon. I'll let you know how it turns out!