Author Topic: Milk left out to acidify - Is it safe?  (Read 269 times)

Offline nugoat

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Milk left out to acidify - Is it safe?
« on: December 18, 2013, 01:03:44 PM »
I'm preparing to make my second cheese, a Queso Oaxaca, and the recipe calls for half of the milk to be left "out for 24 hours until a pH of 5.3 is reached".

I am using pasturized, non-homoginized, whole milk. It is in the 1 quart glass bottles that it came in.

I left the milk out for the 24 hours per the recipe, but it got too late to make the cheese yesterday, so I put it in the fridge and was planning to make the cheese this afternoon. While it certainly looks clabbered, much like the milk I added culture to for another recipe, I started getting paranoid and wondering if it would actually be safe to use.

Are there any general safety guidelines for this sort of thing?

Thanks,

Steve



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Offline Sailor Con Queso

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Re: Milk left out to acidify - Is it safe?
« Reply #1 on: December 18, 2013, 04:10:34 PM »
Unpasteurized raw milk contains many types of native lactic bacteria. Consequently, acidification by natural bacteria is done in many places around the world. When milk is pasteurized, the process kills all of the desirable lactic bacteria and instead leaves only spoilage bacteria. These are the bacteria that make old milk go bad and stink. Raw milk left out will "clabber" naturally while pasteurized milk will simply spoil.

So, I cannot recommend leaving the milk out as your recipe suggested. As a microbiologist, I would not consider this cheese safe for consumption. This recipe was bad advice and I would look for another source.
A moldy Stilton is a thing of beauty. Yes, you eat the rind. - Ed
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Offline nugoat

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Re: Milk left out to acidify - Is it safe?
« Reply #2 on: December 18, 2013, 05:15:27 PM »
Thank you for the response. I kept looking at those bottles thinking that something wasn't right. It was only four quarts that were left out, so it isn't too great of a loss, and a darned sight better than getting sick.

In general, how long can pasteurized milk sit out and still be safe to use? Are there any particular red lines that one shouldn't cross?

Thanks,

Steve

Offline Sailor Con Queso

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Re: Milk left out to acidify - Is it safe?
« Reply #3 on: December 19, 2013, 08:26:15 AM »
Bacteria double their population approximately every 20 minutes so I wouldn't let the milk sit out at all. Even if the milk doesn't "spoil", you might get off flavors.
A moldy Stilton is a thing of beauty. Yes, you eat the rind. - Ed
www.boonecreekcreamery.com

Offline nugoat

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Re: Milk left out to acidify - Is it safe?
« Reply #4 on: December 19, 2013, 12:28:21 PM »
What was I thinking!? I'm making cheese, not compost tea!  ;D


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