Wasted effort making a starter

[Lloyd]

I make my starter, freeze it in ice cube trays, and then defrost some each time I make a batch. Nothing unusual there I'm sure.

Whilst making my latest batch, I suddenly realised than I was following the instructions without thinking.  Heat milk to just below boiling, maintain for 10 minutes, then cool rapidly to 20C.  But I'm using pasteurised milk, and these steps are just pasteurising again. Think I've just saved myself a whole load of extra work.  Or have I missed something?

[Susan38]

Hi Lloyd,

I've read in the Home Cheesemaking book by Rikki Carroll that when making mother cultures you want to totally sterilize the milk, so the starter culture you add in later are the *only* bacteria that are in the milk.  Vat pasteurized milk, as I understand it, does not totally kill all the bacteria, so I think you are correct in what you did.  It's a bit of a bummer that the milk was heat treated twice, but since there is not that much of it added in to your cheese it should not be a big deal?  So I'm thinking your effort was not wasted, but then I'm not an expert on the subject as thus far I've only used direct-set starter cultures. --Susan

[awakephd]

I think Susan is right on target. Consider that pasteurized milk will still spoil in the fridge. Did the pasteurization leave some bacteria behind? Possible ... and also possible that the subsequent handling of the milk allowed bacteria to re-colonize. The only way to keep milk for months or years is to ultrapasteurize it and seal it up immediately, keeping everything sterile all the way through.