No, freezing does not kill bacteria

[Yuri]

Over the years I have seen so many people come and go, saying that freezing fruit is a way to sanitise it. Believe a mircobiologist here, when I say this is not true in the slightest.

Look at the article Walker 2006 Freeze-Thaw Tolerance and Clues to the Winter Survival of a Soil Community. While in some bacteria, like E. coli, viability decreases more quickly with being frozen and thawed, you can see in the graph that it still takes almost 15 cycles freezing for 24-48 hours and thawing again to even see a significant decrease in viability. Microbiologists use freezing all the time to preserve bacteria in a sample, sometimes up to 15 years.

If you have fruit and you are afraid of contamination because of bacteria on this fruit, freezing it once isn't going to do anything for you. You can rinse the fruit in star san or add sulfites to the mix some 48 hours prior, but don't expect to be safe from freezing.

I'm begging you.

 

[MashBag]

I agree with you.
Freezing is a very good way to break down fruit.

Personally I would sulphite, rather than starsan.

What's the pro's & cons of getting a fermentation going quickly and strongly rather than sulphite with clean fruit?

 

[LeeH]

I’ve I thrown in loads of frozen bagged fruit without infection so not worried in the slightest.

 

[MashBag]

I’ve I thrown in loads of frozen bagged fruit without infection so not worried in the slightest.

Me too. I have always understood yeast to have a cleaning effect.

 

[An Ankoù]

I’ve I thrown in loads of frozen bagged fruit without infection so not worried in the slightest.

Me too.

 

[MashBag]

Oh oh, this is turning into a "me too" thread

 

[foxy]

There was an outbreak of salmonella here a couple of years ago tracked back to frozen fruit. All had to be recalled. People died.
Putting frozen fruit into a fermenter is not a good idea.
Yeast as a cure all is an old wives tale dating back to the nineteenth century.

 

[LeeH]

I like living on the edge.

I’m pretty sure the alcohol will get me in the end.

 

[Rodcx500z]

The way things are going, buy this get this kills 99% of germs, we will all die from lack of an immune system

 

[MashBag]

There is certainly some reading on Google that suggests saccharomyces cerevisiae does have a limiting effect. Hmm. off for a read.

 

[MashBag]

The way things are going, buy this get this kills 99% of germs, we will all die from lack of an immune system

So true.

 

[Sadfield]

I refuse to put fruit in beer, it never makes a beer better. So, all good here.

 

[The Baron]

Freezing breaks down the cell structure of fruit to allow extraction of juice easier however if you buy supermarket frozen fruit I believe it has been sanitised/sterilised as you can defrost and eat it on your breakfast and no supermarket would leave themselves open to that risk.

 

[MashBag]

@Sadfield Well said!

 

[MashBag]

Freezing breaks down the cell structure of fruit to allow extraction of juice easier however if you buy supermarket frozen fruit I believe it has been sanitised/sterilised as you can defrost and eat it on your breakfast and no supermarket would leave themselves open to that risk.

Normal Freezing breaks down the cell structure of fruit to allow extraction of juice easier . Tried it a few years ago with a few barrels of grape must.

Lots of commercial produce is blast frozen, to stop that happening.

 

[Agentgonzo]

There is certainly some reading on Google that suggests saccharomyces cerevisiae does have a limiting effect. Hmm. off for a read.

I wonder if it's the yeast, or the alcohol that the yeast produces that kills off stuff.

I've never heard of freezing killing bacteria before though.

 

[foxy]

Freezing breaks down the cell structure of fruit to allow extraction of juice easier however if you buy supermarket frozen fruit I believe it has been sanitised/sterilised as you can defrost and eat it on your breakfast and no supermarket would leave themselves open to that risk.

Read the packet, even though they steam and boil it, it is recommended to heat before using.
Listeria is the most common bacteria on frozen food . Something that will break down one’s immune system not strengthen it.

 

[MashBag]

Are we talking about two things here? Frozen purchased fruit and home grown lobbed into the freezer?

 

[An Ankoù]

I like living on the edge.

I’m pretty sure the alcohol will get me in the end.

Me too.

 

[An Ankoù]

Are we talking about two things here? Frozen purchased fruit and home grown lobbed into the freezer?

We're talking about contamination due to sloppy kitchen procedure and food management.
And grubby little brats that pick their noses and wipe their hands on your tea towels.

Don't try to save a penny by chucking you raspberries into the same freezer bag as your chicken is probably a good starting point.
As for Listeria, we've got it growing up the front of the house. Would be very reluctant to get rid of it. In fact without it;s support, I'd be worried about the integrity of the wall!

Dear Marge,
are we doomed?