Why does olive oil & vinnegar (mixed) need to be refrigerated anyway?
Jeanette Guire
in home-made salad dressing), the recipes all ask for it to be refrigerated
(where it congeals to a gooey mess).
What is different about olive oil + vinnegar + a few spices & salt from a
microbial culture standpoint?
Why must I refrigerate a mix of that which doesn't itself need to be
refrigerated?
Rod Speed
Essentially because the mixing will normally end up contaminating
the mixture, if only because the container wont be sterile.
Ron Peterson
wrote:
> Neither olive oil nor vinnegar need to be refrigerated; yet when mixed (as
> in home-made salad dressing), the recipes all ask for it to be refrigerated
> (where it congeals to a gooey mess).
> What is different about olive oil + vinnegar + a few spices & salt from a
> microbial culture standpoint?
The bacteria need to be in water to live and the oil provides the food
for them to grow.
--
Ron
Goomba38
>> Why must I refrigerate a mix of that which
>> doesn't itself need to be refrigerated?
>
> Essentially because the mixing will normally end up contaminating
> the mixture, if only because the container wont be sterile.
>
They technically weren't sterile beforehand either.
Goomba38
Bacteria do not need water to survive.
That said, I'd be curious if this is just habit or has anyone actually
done study of whether the mixed oil/vinegar require chilling to keep
bacterial load in check? What other ingredients are added tht might
introduce higher risks?
Rod Speed
Goomba38
Not nearly...clean is a far cry from "sterile" which is what I was
responding to.
GreenieLeBrun
Sterility (from a microbiological view)is like virginity it either is or it
isn't no in between.
GreenieLeBrun
Microorganisms such as bacteria and fungi (including yeasts) require a
certain level of "Available Water" to metabolise and grow. Properly made
jams do not have sufficient "Available Water" to permit microbial growth.
Fungi and bacteria can grow (usually anaerobically) at an oil/water
interface an this causes immense problems when water gets in to fuel
storages causing the build up of gunge that can disable jet engines (most
embarrising at 20,000 feet when all engines cut out).
The question is what bacteria are able to grow at the vinegar/oil interface?
My guess would be very few medically important microorganisms if it is good
quality vinegar.
Either make the dressing up in small batches and discard the unused portion
or keep it in the fridge and either zap it in the microwave or warm it up
with warm water before use.
Rod Speed
> Rod Speed wrote:
>> Goomba38 <Goom...@comcast.net> wrote
>>> Rod Speed wrote
>>
>>>>> Why must I refrigerate a mix of that which
>>>>> doesn't itself need to be refrigerated?
>>
>>>> Essentially because the mixing will normally end up contaminating
>>>> the mixture, if only because the container wont be sterile.
>>
>>> They technically weren't sterile beforehand either.
>>
>> The containers they came in were near enough.
> Not nearly...clean is a far cry from "sterile"
They're pretty close to sterile in practice.
Rod Speed
Wrong with new containers for those components.
Rod Speed
The problem with that theory is that the dressing sold ready to use already
has that interface and doesnt require refrigeration until its opened.
Daniel MacKay
You're not listening. Either a container is sterile - that is, a can,
or a jar with an airtight seal, and has been "processed" at a certain
temperature for a certain number of minutes, or it is not. There is no
such thing as "pretty close in practice."
Dressing and mayonnaise containers in the grocery store are not. They
have cardboard seals, are in no way airtight, and have not been
"processed." They *can't* be processed - you can't heat mayonnaise.
Conversely, if you argue that a plastic jar with a cardboard seal is
sufficient to preserve food, you should put up some fruits and
vegetables that way and check back on them in a couple of weeks.
--
Daniel MacKay
Halifax, Nova Scotia, Canada
Phred
I noted various responses to this thread, but my opinion is that it's
the *spices* that will most likely cause a potential problem by
introducing a suite of chemicals that microbes will find useful for
growth. (As well as probably introducing a nice selection of
bacterial spores to start the rot, so to speak. :-)
Also, as others mentioned, bugs that may be able to metabolise
pure olive oil probably require some moisture present to do their
thing, and that would be provided by the vinegar.
Further, if the pH of the final brew is higher than the magic figure
(4.6?) then some common nasties will be able to grow in it.
Cheers, Phred.
--
ppnerk...@THISyahoo.com.INVALID
Daniel T.
As I understand it, the garlic and other herbs put in the dressing may
have botulism spores on them, the oil provides the environment for the
botulism to grow. The vinegar doesn't stop the growth because it
separates too easily from the mix.
You may be able to avoid refrigeration if you first infuse the herbs and
garlic in pure vinegar. However I think the likelihood of spoilage is
greater if you do this. (It may not be toxic, but it will taste bad.)
hchi...@hotmail.com
wrote:
Consistant with the fact that mayonaise can be unrefrigerated, but
that once it is mixed into other foods the mixture can be deadly.
lee h
>
> Consistant with the fact that mayonaise can be unrefrigerated, but
> that once it is mixed into other foods the mixture can be deadly.
It seems you've sampled my Ex's tuna salad. lol.
Rod Speed
>> They're pretty close to sterile in practice.
> You're not listening.
You in spades.
> Either a container is sterile - that is, a can, or a jar with
> an airtight seal, and has been "processed" at a certain
> temperature for a certain number of minutes, or it is not.
> There is no such thing as "pretty close in practice."
You can keep asserting that till you are blue in the face if you like, changes nothing.
> Dressing and mayonnaise containers in the grocery store are not. They
> have cardboard seals, are in no way airtight, and have not been "processed."
And they are close enough to sterile for all practical purposes anyway.
> They *can't* be processed - you can't heat mayonnaise.
We aint talking about mayonnaise.
> Conversely, if you argue that a plastic jar with a cardboard seal
Its got a plastic top as well as the cardboard seal.
> is sufficient to preserve food, you should put up some fruits and
> vegetables that way and check back on them in a couple of weeks.
Having fun thrashing that straw man are you child ?
Rod Speed
> In article <c%AQi.6197$lE2....@newssvr22.news.prodigy.net>, Jeanette
> Guire <jeanet...@sbcglobal.net> wrote:
>> Neither olive oil nor vinnegar need to be refrigerated; yet when
>> mixed (as in home-made salad dressing), the recipes all ask for it
>> to be refrigerated (where it congeals to a gooey mess).
>>
>> What is different about olive oil + vinnegar + a few spices & salt
>> from a microbial culture standpoint?
>>
>> Why must I refrigerate a mix of that which doesn't itself need to be
>> refrigerated?
>
> I noted various responses to this thread, but my opinion is that it's
> the *spices* that will most likely cause a potential problem by
> introducing a suite of chemicals that microbes will find useful for
> growth. (As well as probably introducing a nice selection of
> bacterial spores to start the rot, so to speak. :-)
Doesnt explain why the ready to use stuff with the spices already in it keeps
fine until its opened and needs to be refrigerated once its been opened.
> Also, as others mentioned, bugs that may be able to metabolise
> pure olive oil probably require some moisture present to do their
> thing, and that would be provided by the vinegar.
See above.
> Further, if the pH of the final brew is higher than the magic figure
> (4.6?) then some common nasties will be able to grow in it.
See above.
Rod Speed
> Jeanette Guire <jeanet...@sbcglobal.net> wrote:
>
>> Neither olive oil nor vinnegar need to be refrigerated; yet when
>> mixed (as in home-made salad dressing), the recipes all ask for it
>> to be refrigerated (where it congeals to a gooey mess).
>>
>> What is different about olive oil + vinnegar + a few spices & salt
>> from a microbial culture standpoint?
>>
>> Why must I refrigerate a mix of that which doesn't itself need to be
>> refrigerated?
>
> As I understand it, the garlic and other herbs put in the dressing may
> have botulism spores on them, the oil provides the environment for the
> botulism to grow. The vinegar doesn't stop the growth because it
> separates too easily from the mix.
Doesnt explain why the ready to use stuff keeps fine unrefrigerated
but you need to refrigerate it once its been opened.
> You may be able to avoid refrigeration if you
> first infuse the herbs and garlic in pure vinegar.
You're unlikely to be able to do that in a sterile situation without a lot of trouble.
> However I think the likelihood of spoilage is greater if you do this.
Corse it is.
E Z Peaces
Cheap olive oil goes rancid faster than good oil because cheap oil is
more acidic. Also, if you keep your olive oil refrigerated, you may get
condensation in the oil when you have the cold bottle out and open.
Moisture may soon spoil the flavor.
So when you add vinegar and water, the oil will deteriorate faster.
Each time you shake it, you mix air into it.
John Weiss
>>>>>> Why must I refrigerate a mix of that which
>>>>>> doesn't itself need to be refrigerated?
>>>
>>>>> Essentially because the mixing will normally end up contaminating
>>>>> the mixture, if only because the container wont be sterile.
>>>
>>>> They technically weren't sterile beforehand either.
>>>
>>> The containers they came in were near enough.
>
>> Not nearly...clean is a far cry from "sterile"
>
> They're pretty close to sterile in practice.
Nope. Once the containers are opened, they are no longer sterile. After
being used many times and opened & closed repeatedly, they are no longer
sterile. The container used for the mixture may be as clean or cleaner
than the bottles of oil & vinegar.
FWIW, many restaurants keep salad dressings in unrefrigerated containers.
If you use them up in a reasonable time (a few days) there is no need to
refrigerate them.
OTOH, repeated shaking of the mixture will aerate it, and possibly
accelerate the oxidation of the olive oil, which will change its taste and
aroma. Refrigeration may help delay that oxidation.
OhioGuy
some of the oil. The resulting mixture may be less acidic, and therefore
easier for microbes to grow in. Plus, as some have mentioned, the act of
pouring both ingredients into a mixing container probably contaminates it
with at least a few microbes anyway.
Rod Speed
> Rod Speed <rod.sp...@gmail.com> wrote...
>>>>>>> Why must I refrigerate a mix of that which
>>>>>>> doesn't itself need to be refrigerated?
>>>>>> Essentially because the mixing will normally end up contaminating
>>>>>> the mixture, if only because the container wont be sterile.
>>>>> They technically weren't sterile beforehand either.
>>>> The containers they came in were near enough.
>>> Not nearly...clean is a far cry from "sterile"
>> They're pretty close to sterile in practice.
> Nope.
Yep.
> Once the containers are opened, they are no longer sterile. After being used many times and opened & closed
> repeatedly, they are no longer sterile.
And few bother to refrigerate olive oil and vinegar once they have
been opened and the container doesnt say that you should either.
> The container used for the mixture may be as clean or cleaner than the bottles of oil & vinegar.
Unlikely given that the container will have been washed
in the home, and not new in the manufacturing plant.
> FWIW, many restaurants keep salad dressings in unrefrigerated
> containers. If you use them up in a reasonable time (a few days)
> there is no need to refrigerate them.
Irrelevant to the question that was asked.
Brian Mailman
> Daniel T. <dani...@earthlink.net> wrote:
>> Jeanette Guire <jeanet...@sbcglobal.net> wrote:
>>> Why must I refrigerate a mix of that which doesn't itself need to be
>>> refrigerated?
>>
>> As I understand it, the garlic and other herbs put in the dressing may
>> have botulism spores on them, the oil provides the environment for the
>> botulism to grow. The vinegar doesn't stop the growth because it
>> separates too easily from the mix.
>
> Doesnt explain why the ready to use stuff keeps fine unrefrigerated
> but you need to refrigerate it once its been opened.
How about what "we" say over here in rfp when a similar question comes
up: "Commercial producers have equipment and techniques not available
to the home cook."
B/
GreenieLeBrun
No, not unless those containers were sterilised via autoclaving, hot air
(160C), or gamma irradiation.
GreenieLeBrun
You will find that these commercial dressings contain preservatives that
inhibit the growth of microorganisms
Rod Speed
They end up close enough to sterile due to the manufacturing process.
Rod Speed
Mine doesnt.
GreenieLeBrun
There is no such thing as "close enough to sterile". Sterility is an
absolute. Granted, the vessels will be, in all probability, very clean but
that is the best that can be claimed.
Bob F
<hchi...@hotmail.com> wrote in message
news:s297h3hakjmmgvo8e...@4ax.com...
Doesn't it usually say "refrigerate after opening"?
Bob
Rod Speed
> Rod Speed wrote:
>> GreenieLeBrun <Greeni...@hotmail.com> wrote:
>>> Rod Speed wrote:
>>>> GreenieLeBrun <Greeni...@hotmail.com> wrote:
>>>>> Rod Speed wrote:
>>>>>> Goomba38 <Goom...@comcast.net> wrote
>>>>>>> Rod Speed wrote
>>>>>>
>>>>>>>>> Why must I refrigerate a mix of that which
>>>>>>>>> doesn't itself need to be refrigerated?
>>>>>>
>>>>>>>> Essentially because the mixing will normally end up
>>>>>>>> contaminating the mixture, if only because the container wont
>>>>>>>> be sterile.
>>>>>>
>>>>>>> They technically weren't sterile beforehand either.
>>>>>>
>>>>>> The containers they came in were near enough.
>>>>>
>>>>> Sterility (from a microbiological view)is like virginity it either
>>>>> is or it isn't no in between.
>>>>
>>>> Wrong with new containers for those components.
>>>
>>> No, not unless those containers were sterilised via autoclaving, hot
>>> air (160C), or gamma irradiation.
>>
>> They end up close enough to sterile due to the manufacturing process.
> There is no such thing as "close enough to sterile". Sterility is an absolute.
Wrong, as always. A freshly manufactured glass bottle is close
enough to sterile just because of the process used to make it.
> Granted, the vessels will be, in all probability, very clean but that is the best that can be claimed.
Same thing, different words.
just joe
>
>> There is no such thing as "close enough to sterile". Sterility is an
>> absolute.
>
> Wrong, as always. A freshly manufactured glass bottle is close
> enough to sterile just because of the process used to make it.
>
>> Granted, the vessels will be, in all probability, very clean but that is
>> the best that can be claimed.
>
> Same thing, different words.
>
uh, rod buddy, words mean something.
sterile will never mean close enough to sterile.
different words mean different things.
amazon.com has some good deals on dictionaries.
Daniel MacKay
> Having fun thrashing that straw man are you child ?
Don't take my word for it. do it.
Rod Speed
> Rod Speed wrote
>> Daniel MacKay <dan...@bonmot.ca> wrote:
>>>> They're pretty close to sterile in practice.
>>> You're not listening.
>> You in spades.
>>> Either a container is sterile - that is, a can, or a jar with
>>> an airtight seal, and has been "processed" at a certain
>>> temperature for a certain number of minutes, or it is not.
>>> There is no such thing as "pretty close in practice."
>> You can keep asserting that till you are blue in the face if you like, changes nothing.
>>> Dressing and mayonnaise containers in the grocery store are not. They
>>> have cardboard seals, are in no way airtight, and have not been "processed."
>> And they are close enough to sterile for all practical purposes anyway.
>>> They can't be processed - you can't heat mayonnaise.
>> We aint talking about mayonnaise.
>>> Conversely, if you argue that a plastic jar with a cardboard seal
>> Its got a plastic top as well as the cardboard seal.
>>> is sufficient to preserve food, you should put up some fruits and
>>> vegetables that way and check back on them in a couple of weeks.
>> Having fun thrashing that straw man are you child ?
> Don't take my word for it. do it.
No thanks, it aint relevant to what is actually being discussed.
Rod Speed
>>>> They end up close enough to sterile due to the manufacturing
>>>> process.
>>
>>> There is no such thing as "close enough to sterile". Sterility is an
>>> absolute.
>>
>> Wrong, as always. A freshly manufactured glass bottle is close
>> enough to sterile just because of the process used to make it.
>>
>>> Granted, the vessels will be, in all probability, very clean but
>>> that is the best that can be claimed.
>>
>> Same thing, different words.
> uh, rod buddy, words mean something.
And in that particular case, they mean essentially the same thing.
> sterile will never mean close enough to sterile.
And close enough to sterile has a different meaning to sterile.
> different words mean different things.
And in that particular case, they mean essentially the same thing.
> amazon.com has some good deals on dictionaries.
Only a fool bothers with that sort of dinosaur technology when there are so many online.
Daniel T.
> > As I understand it, the garlic and other herbs put in the
> > dressing may have botulism spores on them, the oil provides the
> > environment for the botulism to grow. The vinegar doesn't stop
> > the growth because it separates too easily from the mix.
>
> Doesnt explain why the ready to use stuff keeps fine unrefrigerated
> but you need to refrigerate it once its been opened.
Commercial salad dressings and acidified sauces are
microbiologically safe. Manufacturers follow strict quality
controls and diligently comply with FDA-mandated Good
Manufacturing Practices in production of these commercial
products. Commercial salad dressing and sauce products are also
made with pasteurized eggs that are free of Salmonella and other
pathogenic bacteria and further ensure the safety of these
products. As such, these commercial products do not have the food
safety risks associated with their homemade counterparts, which
contain unpasteurized eggs. Homemade versions also may not
contain sufficient quantities of food acids like vinegar (acetic
acid) or lemon juice (citric acid) to kill harmful
microorganisms.
(http://www.cfsan.fda.gov/~mow/chap1sal.html)
just joe
>> amazon.com has some good deals on dictionaries.
>
> Only a fool bothers with that sort of dinosaur technology when there are
> so many online.
>
kinda why i suggested it to you...................................
Logan Shaw
Well, you learn something new every day. Rod Speed has his own brand
of salad dressing, just like Paul Newman. I never would've guessed it.
- Logan
hchi...@hotmail.com
wrote:
>> Consistant with the fact that mayonaise can be unrefrigerated, but
>> that once it is mixed into other foods the mixture can be deadly.
>
>Doesn't it usually say "refrigerate after opening"?
You obviously know my old girlfriend.
Rod Speed
Never ever could bullshit its way out of a wet paper bag.
Even someone as stupid as you should be able to find countless
examples of where I have posted a link to an online dictionary.
Rod Speed
Pathetic.
Rod Speed
>>> As I understand it, the garlic and other herbs put in the dressing
>>> may have botulism spores on them, the oil provides the
>>> environment for the botulism to grow. The vinegar doesn't stop
>>> the growth because it separates too easily from the mix.
>> Doesnt explain why the ready to use stuff keeps fine unrefrigerated
>> but you need to refrigerate it once its been opened.
> Commercial salad dressings and acidified sauces are microbiologically safe.
They do however tell you to refrigerate after opening. There's a reason for that.
> Manufacturers follow strict quality controls and diligently
> comply with FDA-mandated Good Manufacturing
> Practices in production of these commercial products.
See above.
> Commercial salad dressing and sauce products are also made with pasteurized eggs
Not the ones being discussed, those dont contain any eggs at all.
> that are free of Salmonella and other pathogenic bacteria
> and further ensure the safety of these products.
See above.
> As such, these commercial products do not have
> the food safety risks associated with their homemade
> counterparts, which contain unpasteurized eggs.
Not the ones being discussed, those dont contain any eggs at all.
> Homemade versions also may not contain sufficient
> quantities of food acids like vinegar (acetic acid) or
> lemon juice (citric acid) to kill harmful microorganisms.
Unlikely with the mixture being discussed, see the subject.
> (http://www.cfsan.fda.gov/~mow/chap1sal.html)
Not relevant to what is being discussed.
just joe
> Never ever could bullshit its way out of a wet paper bag.
>
look up the word 'grammar'. you could probably find a good book on
amazon.com
William Souden
>
> Pathetic.
>
>
You certainly are, welfare boy.
William Souden
John Weiss
>
> Wrong, as always. A freshly manufactured glass bottle is close
> enough to sterile just because of the process used to make it.
So, what does that have to do with the state of olive oil or vinegar?
Packaging plants don't manufacture bottles; they fill bottles that have
been made elsewhere and shipped.
Rod Speed
Rod Speed
> Rod Speed <rod.sp...@gmail.com> wrote
>> GreenieLeBrun <Greeni...@hotmail.com> wrote
>>> Rod Speed wrote
>>>> GreenieLeBrun <Greeni...@hotmail.com> wrote
>>>>> Rod Speed wrote
>>>>>> GreenieLeBrun <Greeni...@hotmail.com> wrote
>>>>>>> Rod Speed wrote
>>>>>>>> Goomba38 <Goom...@comcast.net> wrote
>>>>>>>>> Rod Speed wrote
>>>>>>>>>>> Why must I refrigerate a mix of that which
>>>>>>>>>>> doesn't itself need to be refrigerated?
>>>>>>>>>> Essentially because the mixing will normally end up contaminating the mixture, if only because the container
>>>>>>>>>> wont be sterile.
>>>>>>>>> They technically weren't sterile beforehand either.
>>>>>>>> The containers they came in were near enough.
>>>>>>> Sterility (from a microbiological view)is like virginity it either is or it isn't no in between.
>>>>>> Wrong with new containers for those components.
>>>>> No, not unless those containers were sterilised via autoclaving, hot air (160C), or gamma irradiation.
>>>> They end up close enough to sterile due to the manufacturing process.
>>> There is no such thing as "close enough to sterile". Sterility is an absolute.
>> Wrong, as always. A freshly manufactured glass bottle is close
>> enough to sterile just because of the process used to make it.
> So, what does that have to do with the state of olive oil or vinegar?
Everything to do with the fact that they are sterile enout for all practical purposes.
> Packaging plants don't manufacture bottles; they fill bottles that have been made elsewhere and shipped.
Duh.
E Z Peaces
Bacteria don't have to be involved. Why do canned goods go bad in
months or years (depending on what food it is)? Why does unopened
cooking oil go bad in months? Why does expensive olive oil have a
longer shelf life?
They deteriorate chemically. When you make dressing, you add water,
acid, and air to olive oil. They speed the deterioration.
just joe
>
>> look up the word 'grammar'. you could probably find a good book on
>> amazon.com
>
> Never ever could bullshit its way out of a wet paper bag.
>
>
er, uh, um, skippy?? you already wrote that. i think you're missing a verb.
but, whatever. your attempts at insults are so pedestrian that i'm amused
rather than offended. try some of these:
http://b3ta.com/questions/insults/
they speak english, so if you need help with translations, you have my
addie.
to save on postage, when you order your dictionary and grammar book, get a
thesaurus (you may need to look that word up), and the autobiography of ben
franklin (now he was a man that could drop an insult) or something on the
rich history of the algonquin club; dorthy parker et al.
but, you've been poked with a fork and you're done.
Rod Speed
just joe <don....@alaska.com> wrote just the
puerile shit thats all it can ever manage.
William Souden
and over. Took him forever to figure out he was misspelling "puerile".
Come on, welfare boy, show us the flushing routine.
zxcvbob
> Daniel T. <dani...@earthlink.net> wrote
>> Rod Speed <rod.sp...@gmail.com> wrote
>>> Daniel T. <dani...@earthlink.net> wrote:
>
>>>> As I understand it, the garlic and other herbs put in the dressing
>>>> may have botulism spores on them, the oil provides the
>>>> environment for the botulism to grow. The vinegar doesn't stop
>>>> the growth because it separates too easily from the mix.
>
>>> Doesnt explain why the ready to use stuff keeps fine unrefrigerated
>>> but you need to refrigerate it once its been opened.
>
>> Commercial salad dressings and acidified sauces are microbiologically safe.
>
> They do however tell you to refrigerate after opening. There's a reason for that.
The main reason is because the taste better that way.
Bob
Cheeky Bastard
anyhow.
Do as you wish with it. Do you think most care?
Maybe you have a dorm room fridge? <grin>
"Rod Speed" <rod.sp...@gmail.com> wrote in message
news:5nhpgqF...@mid.individual.net...
> Daniel MacKay <dan...@bonmot.ca> wrote:
>
>>> They're pretty close to sterile in practice.
>
>> You're not listening.
>
> You in spades.
>
>> Either a container is sterile - that is, a can, or a jar with
>> an airtight seal, and has been "processed" at a certain
>> temperature for a certain number of minutes, or it is not.
>> There is no such thing as "pretty close in practice."
>
> You can keep asserting that till you are blue in the face if you like,
> changes nothing.
>
>> Dressing and mayonnaise containers in the grocery store are not. They
>> have cardboard seals, are in no way airtight, and have not been
>> "processed."
>
> And they are close enough to sterile for all practical purposes anyway.
>
Cheeky Bastard
not post and just do as you are going to anyway.
"Rod Speed" <rod.sp...@gmail.com> wrote in message
news:5ni7a8F...@mid.individual.net...
> John Weiss <jrw...@nospamattglobal.net> wrote
>> Rod Speed <rod.sp...@gmail.com> wrote...
>
>>>>>>>> Why must I refrigerate a mix of that which
>>>>>>>> doesn't itself need to be refrigerated?
>
>>>>>>> Essentially because the mixing will normally end up contaminating
>>>>>>> the mixture, if only because the container wont be sterile.
>
>>>>>> They technically weren't sterile beforehand either.
>
>>>>> The containers they came in were near enough.
>
>>>> Not nearly...clean is a far cry from "sterile"
>
>>> They're pretty close to sterile in practice.
>
>> Nope.
>
> Yep.
>
>> Once the containers are opened, they are no longer sterile. After being
>> used many times and opened & closed repeatedly, they are no longer
>> sterile.
>
> And few bother to refrigerate olive oil and vinegar once they have
> been opened and the container doesnt say that you should either.
>
>> The container used for the mixture may be as clean or cleaner than the
>> bottles of oil & vinegar.
>
> Unlikely given that the container will have been washed
> in the home, and not new in the manufacturing plant.
>
>> FWIW, many restaurants keep salad dressings in unrefrigerated
>> containers. If you use them up in a reasonable time (a few days)
>> there is no need to refrigerate them.
>
> Irrelevant to the question that was asked.
>
>> OTOH, repeated shaking of the mixture will aerate it, and possibly
>> accelerate the oxidation of the olive oil, which will change its
>> taste and aroma. Refrigeration may help delay that oxidation.
>
>
>
Cheeky Bastard
Besides we use the ovlive oil way before it is in question.
We also have known you can cook with it as long as you never hit the flash
point of the oil.
"Rod Speed" <rod.sp...@gmail.com> wrote in message
news:5ngjckF...@mid.individual.net...
> GreenieLeBrun <Greeni...@hotmail.com> wrote:
>> Rod Speed wrote:
>>> Goomba38 <Goom...@comcast.net> wrote
>>>> Rod Speed wrote
>>>
>>>>>> Why must I refrigerate a mix of that which
>>>>>> doesn't itself need to be refrigerated?
>>>
>>>>> Essentially because the mixing will normally end up contaminating
>>>>> the mixture, if only because the container wont be sterile.
>>>
>>>> They technically weren't sterile beforehand either.
>>>
>>> The containers they came in were near enough.
>>
dank
> On Oct 14, 10:18 pm, Jeanette Guire <jeanettegu...@sbcglobal.net>
> wrote:
>
>>Neither olive oil nor vinnegar need to be refrigerated; yet when mixed (as
>>in home-made salad dressing), the recipes all ask for it to be refrigerated
>>(where it congeals to a gooey mess).
>
>
>>What is different about olive oil + vinnegar + a few spices & salt from a
>>microbial culture standpoint?
>
>
> The bacteria need to be in water to live and the oil provides the food
> for them to grow.
That sounds right. The vinegar is normally acidic enough to prevent
bacterial growth and the oil normally can't support bacteria, but
when the vinegar is diluted the pH increases enough to support
growth, and the vinegar contains lots of micronutrients. The spices
add even more nutrients.