Using PET bottles for long term storage of wort

I managed to get a few 1 Litre Pet Bottles, formerly from a Biology lab (they were used to store water). I was wondering does anyone know of a good way to santise these for storage of wort.

I was hoping to use them to make up a couple of litres of wort and then freeze/refridgerate it and defrost and use for a starter. My biggest concern is sterilizing it. I have access to fairly horrific amounts of isopropyl and starsan. Would one of these or an alternative be the best way to sanizise the bottle effectively?

Why not just boil the wort before making the starter? I have some right out of the mash tun froze in a food saver bag.

IIRC, boiling wort won't sterilize it and you would be running a risk with anything less than pressure canning. The risk is probably very small, but the stakes are very high. Just an FYI as I am not an expert on this or any other subject. Google botulism for some frightening information.

I've never sterilized anything. Boiling may not kill botulism spores but it does destroy it's toxin. Freezing the wort limits any growth to about none anyway, as does the pH of fermenting wort.

The easiest thing, in my opinion, is to invest in a box of quart freezer bags. They're easy to use, cheap, and disposable. Also, as other say freezing them will keep the nasties from reproducing.