Garlic in Olive Oil Safety

[Vision]

Hi everyone, first post here. I've worked in a few restaurants including a high end Italian one, which brings me to...

The cooks would make this garlic and oil pasta for us which was unbelievable. Nothing complex, but the chopped garlic used was held in olive oil, all kept in a bucket in the walk in.

Do you know what it tastes like when garlic starts to develop that richness of flavor? When you first cut and saute it in oo, it's not all that flavorful. But...at some point after sitting in oo it develops this wonderful, rich, rounded, pungent taste which I can't get enough of. You can't get it from infusing oil with garlic.

And there's all these warnings about keeping garlic in oo and botulism. But how can it be?

At this restaurant, besides the bucket, each table got a bottle of oo with garlic cloves and herbs in it. They would change the garlic/herb mix every month or so, but always kept the oil. Nobody ever got sick, and the oil was great. I once asked the old Italian chef/owner about Botulism and he had no idea what I was talking about.

So my questions are, does anyone know the taste I'm talking about? Does anyone know how to create this flavor? So far I can't do it; must not let it sit long enough.

Right now I've got a bulb chopped and sitting in oil. I leave it out for a few hours a day and keep it in the fridge at night and during the day.

What do people with experience think off all the botulism warnings? Overblown? It has to be. Some of these warnings even say to not keep garlic in oil in the fridge; but botulism spores only grow above 40 degrees. And haven't you see bottles of oil containing entire cloves in it?

[Lactic Solar Dust]

At the 1st restaurant I cooked in the chef instructed us to pass a container full of garlic cloves through a meat grinder into a bucket and cover the "crushed" garlic with olive oil. We cooked with this stuff and the service staff placed little ramekins of it on the tables for the customers to dip their bread in. Personally, I wasn't down with it, thought it was quite disrespectful to the product to ram it through a meat grinder (I didn't work very long at that restaurant).

I choose to sous-vide my garlic with olive oil and salt. The final product is a perfectly infused oil with very sweet garlic.

Edited July 7, 2009 by Lactic Solar Dust (log)

[nickrey]

It appears that the link between garlic in olive oil and botulism poisoning stems from an incident where three people suffered botulism poisoning after consuming garlic bread made from garlic in olive oil. Check this link for the abstract of the report.

Garlic is a low acid food. When you put such foods in olive oil where there is no oxygen and store them at room temperature, it gives ideal conditions for botulism to grow. So why isn't this form of poisoning more common? Put simply, botulism has to be there in the first place for it to grow. This is obviously far from a regular occurrence. But food safety processes are there to prevent known risk factors: just because it hasn't happened yet doesn't mean it won't happen.

The acidifying agents referred to in the article as being required by the FDA act to make the oil medium unsuitable for botulism to grow. I'm not sure what effect this would have on the garlic flavor you were talking about.

[Heartsurgeon]

i typically take an entire head of garlic, run the cloves through a garlic press, and cover the garlic mash with 1/4-1/2 cup of olive oil. i let the oil/garlic mixture sit out for anywhere from a few minutes to an hour, and use it during the meal prep.

i pour some oil through a sieve, and use it to dress a salad (with lemon or balsamic vinegar, salt, pepper)

i use some of the oil to cook/sear with.

the garlic mash can be added to a pot of rice that is cooking (amazing flavor in the rice), to a soup, stock, or sauce.

whatever is left over, i discard. Easy to make this freah, everytime you use it.

the idea of storing it (uncooked) for a long period of time is unappealing to me. short term use (used the same day)...no problems.

[andiesenji]

I never use cold-infused garlic in oil. While the incidence of botulism is low, it does exist and I do not want to be the one statistic.

I oven-roast garlic in oil in a Corning pot. I buy the peeled garlic cloves sold by Costco, Sam's Club or Smart & Final in the large containers.

You can chop it if you wish - I always leave the garlic cloves whole because I like it that way.

Cover the garlic with two liters, or more, of garlic oil - doesn't have to be extra-virgin, I happen to like a Greek brand that comes in a big tin.

Place in the oven at 275 F., and roast for 2 1/2 to 3 hours until the garlic is nicely caramelized.

Taste it.

Transfer to a glass container with a tight-fitting lid.

This does not need refrigeration and will keep for months.

Do use care in removing the garlic and whatever oil you want to use. I use a ladle which I have rinsed with boiling water. You don't want to introduce any other foodstuff into the oil.

In this photo, you can see the roasted garlic cloves scattered over a pan full of raw vegetables ready for roasting and the oil has been used to dress and flavor the vegetables.

Having the garlic and oil ready for use in this manner saves me a great deal of time.

This is the gallon jar that lives in my pantry.

Edited July 7, 2009 by andiesenji (log)

[mr.baconhead]

I never use cold-infused garlic in oil.  While the incidence of botulism is low, it does exist and I do not want to be the one statistic.

I oven-roast garlic in oil in a Corning pot.  I buy the peeled garlic cloves sold by Costco, Sam's Club or Smart & Final in the large containers.

You can chop it if you wish - I always leave the garlic cloves whole because I like it that way.

Cover the garlic with two liters, or more, of garlic oil - doesn't have to be extra-virgin, I happen to like a Greek brand that comes in a big tin. 

Place in the oven at 275 F., and roast for 2 1/2 to 3 hours until the garlic is nicely caramelized. 

Taste it.

Transfer to a glass container with a tight-fitting lid. 

This does not need refrigeration and will keep for months.

I've been wanting to try this ever since I saw the tubs of organic garlic at Costco, but always wondered about the bots/storage thing.

Is there a disadvantage to doing this on the stovetop instead of in the oven?

[OliverB]

my relatives (who are Italian on one side and live in Reggio Emilia) make a very simple spaghetti alio e olio (spelling?) by just smashing garlic, mixing with oil and mixing all that into the hot pasta. Some salt, basil, parsley or red pepper and parmesan. Super easy and one of those foods I want a tub full of to sit in :-)

Of course, that area of Italy is full of those things~~

It's all done fresh though, not sure what might or might not have developed in that bucket of oil and garlic, though I doubt the garlic changes much when it's just sitting in oil. Well, it'll deteriorate eventually I guess.

If I'd want to try this I'd get the peeled garlic mentioned, throw it for a couple sec into boiling water and then directly into oil. And I'd put that in the fridge I think.

[Lisa Shock]

The garlic must get to 250° for at least 5 minutes to kill the botulism.

Boiling water temperatures WILL NOT kill it even after hours at boiling temperatures.

Most strains thrive at refrigeration temperatures, so refrigeration after making oil won't retard growth if you didn't kill it while processing.

There have been instances of botulism poisoning from garlic oil made from roasted garlic. So, you need to be careful while roasting.

Here in Phoenix, it's a violation of the health code to make or serve garlic oil, regardless of how it is handled.

The FDA recommends processing the garlic with vinegar from the start, so that you get an acid environment that is hostile to botulism.

[AVFOOL]

At the 1st restaurant I cooked in the chef instructed us to pass a container full of garlic cloves through a meat grinder into a bucket and cover the "crushed" garlic with olive oil.  We cooked with this stuff and the service staff placed little ramekins of it on the tables for the customers to dip their bread in.  Personally, I wasn't down with it, thought it was quite disrespectful to the product to ram it through a meat grinder (I didn't work very long at that restaurant).

I choose to sous-vide my garlic with olive oil and salt.  The final product is a perfectly infused oil with very sweet garlic.

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SV garlic with olive oil and salt at what temp. and how long?

[Vision]

Most strains thrive at refrigeration temperatures, so refrigeration after making oil won't retard growth if you didn't kill it while processing.

←

Botulism as I've read, grows from 40 to 140f.

[OliverB]

now I'm curious, I'll have to dig for some of my garlic oil recipes later on. I do remember that none of them keep long at all, which is why I never made them. Well, at least not to keep and store, just fresh to be used that day.

Can't somebody just come up with vaccination for botulism? The culinary doors this could open....

;-p

[David A. Goldfarb]

I've been using Bourdain's garlic confit method from the _Les Halles Cookbook_ lately, which is 2-3 heads of garlic separated, but roasted with the peels on in a little olive oil and maybe some thyme at 375 F for around 20-25 minutes (I don't have the book in front of me, but off the top of my head, I think I've got it all in there). The garlic cloves are popped out of the peels after cooling, and the garlic and oil can be chilled. As I recall, he does it in an aluminum foil packet, but I just use a small copper casserole.

The garlic has a nice rounded flavor this way, and it's easy enough to make that I don't need to make more than I can use in a reasonable amount of time, which I usually consider to be up to a month, though if I were being really careful, I would probably use it within a week.

[andiesenji]

now I'm curious, I'll have to dig for some of my garlic oil recipes later on. I do remember that none of them keep long at all, which is why I never made them. Well, at least not to keep and store, just fresh to be used that day.

Can't somebody just come up with vaccination for botulism? The culinary doors this could open....

;-p

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Irradiation would be even better.

Please note that there is a great deal of information in this thread.

see my post #18.

And here is the technical data.

Believe me, I spent a considerable amount of time investigating the various possibilities of pathogens being incorporated into various foods and how to avoid same.

I have been canning all kinds of food for most of my life and I studied all the farm bureau bulletins.

I am now seventy.

Roasting or "boiling" the garlic in sufficient oil, for the recommended time, will kill the pathogen.

Olive oil boils at 375 degrees F., in the oven at 275 F., it will reach 250 degrees after one hour, fifteen minutes, more rapidly if the oven temp is higher, but it might boil over, thus the reason I use 275.

The additional time is to allow the garlic to reach the optimum flavor. In the numerous batches I have cooked, two hours is close to optimum but I have let it go longer when I was out of the kitchen for extra time.

I also have a long history of work in the medical field, trained as both a medical laboratory technician and an x-ray technician.

Edited July 8, 2009 by andiesenji (log)

[Lactic Solar Dust]

At the 1st restaurant I cooked in the chef instructed us to pass a container full of garlic cloves through a meat grinder into a bucket and cover the "crushed" garlic with olive oil.  We cooked with this stuff and the service staff placed little ramekins of it on the tables for the customers to dip their bread in.  Personally, I wasn't down with it, thought it was quite disrespectful to the product to ram it through a meat grinder (I didn't work very long at that restaurant).

I choose to sous-vide my garlic with olive oil and salt.  The final product is a perfectly infused oil with very sweet garlic.

←

SV garlic with olive oil and salt at what temp. and how long?

←

60F for 6 hours; I also place a few sprigs of thyme in there as well.

[dondford]

I had a good garlic crop this year and wanted to store some in oil in the fridge; I have done this in the past with no problem. I have read several warning lately about the danger of botulism using this method. I see minced garlic in oil in the grocery store and assume they use some type pf preservative. I am wondering if adding a pinch of pink salt may be a good idea. What do you guys think.

Don

[dougal]

I had a good garlic crop this year and wanted to store some in oil in the fridge; I have done this in the past with no problem.  I have read several warning lately about the danger of botulism using this method.  I see minced garlic  in oil in the grocery store and assume they use some type pf preservative.  I am wondering if adding a pinch of pink salt may be a good idea.  What do you guys think.

←

Commercially, its usually processed to 'canning' temperatures.

That sort of heat/time is required to make a sufficient dent in the number of spores, from which the bacteria re-grow.

The bugs die before 60C, the toxin decomposes around 75C, but it takes 120C to hit the spores.

There are lots of different varieties of c. botulinum, with their own particular susceptibilities.

The research paper I read sometime back concluded that garlic oil could be safely stored under refrigeration for at least a couple of weeks. The growth rate is severely reduced - though not stopped entirely.

The bacteria are found in the soil, the earth (US 'dirt'?).

Making sure that no trace whatsoever of soil or outer skin gets anywhere near your oil should go a long way to keeping that soil (and soil-contacted garlic), and hence the bacteria, out of your oil.

The impossibility of ensuring that a commercial operation treats garlic skin as toxic waste (which it isn't quite) probably accounts for blanket prohibitions.

IMHO, carefully rinsing (and then hygienically air-drying) the carefully peeled cloves before introducing them to cold oil (and storing in the fridge for less than two weeks) should give a product that is as safe as anything else you might do in your kitchen.

If one rinsed the peeled cloves in a pretty dilute solution of ('pink') curing salt, that should add another "hurdle", though not a conventional one.

[andiesenji]

Commercially, its usually processed to 'canning' temperatures.

That sort of heat/time is required to make a sufficient dent in the number of spores, from which the bacteria re-grow.

The bugs die before 60C, the toxin decomposes around 75C, but it takes 120C to hit the spores.

←

The toxins have to be subjected to at least 85C for a minimum of five minutes.

Botulinus technical info.

[Restorer]

The bacteria are found in the soil, the earth (US 'dirt'?).

Making sure that no trace whatsoever of soil or outer skin gets anywhere near your oil should go a long way to keeping that soil (and soil-contacted garlic), and hence the bacteria, out of your oil.

The impossibility of ensuring that a commercial operation treats garlic skin as toxic waste (which it isn't quite) probably accounts for blanket prohibitions.

IMHO, carefully rinsing (and then hygienically air-drying) the carefully peeled cloves before introducing them to cold oil (and storing in the fridge for less than two weeks) should give a product that is as safe as anything else you might do in your kitchen.

If one rinsed the peeled cloves in a pretty dilute solution of ('pink') curing salt, that should add another "hurdle", though not a conventional one.

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Does that imply that you could be safest if you followed that procedure using garlic you've grown yourself, in sterile potting mix? Also, maybe a dilute bleach solution would be better for rinsing.

[thampik]

I have gone right off the idea of garlic-infused olive oil :-)

[mtigges]

Put simply, botulism has to be there in the first place for it to grow. This is obviously far from a regular occurrence.

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While I'm not sure what exactly you mean by "regular" be aware that botulism spores are commonly found throughout soils in North America.

It should never be assumed that anything harvested from your garden is free of botulism spores.

[andiesenji]

Put simply, botulism has to be there in the first place for it to grow. This is obviously far from a regular occurrence.

←

While I'm not sure what exactly you mean by "regular" be aware that botulism spores are commonly found throughout soils in North America.

It should never be assumed that anything harvested from your garden is free of botulism spores.

←

You are entirely correct. Even foods that do not come in contact with the soil - runner beans, for instance, green peas, or peppers etc., can have the botulinus organisms on them. Foods like this have to be pressure canned because, as noted above, boiling will not destroy the pathogen. Foods that have been pressure-washed and treaded with a solution of bleach in water have been tested and live botulinus organisms cultured.

However, as long as the food is consumed immediately and is not stored in an oxygen-free environment (canned or vacuum-sealed - or under oil) for a prolonged period at room temp, it is safe to eat.

Storing low-acid foods under oil or fat when they have not been cooked at a sufficient temp for long enough can be a problem.

One type of botulism is found in marine environments and can contaminate fish - which is why processors pressure cook any fish that is going to be canned either in oil or water.

Even if you use a "sterile" soil, if it is exposed to the air, the organisms can arrive from hundreds or thousands of miles away, borne by dust.

I never thought much about this until I read "The Secret Life of Dust" by Hannah Holmes seven or eight years ago. It is an eye-opener, especially if one gardens anywhere in the western U.S.

Edited July 9, 2009 by andiesenji (log)

[jgm]

Most strains thrive at refrigeration temperatures, so refrigeration after making oil won't retard growth if you didn't kill it while processing.

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Botulism as I've read, grows from 40 to 140f.

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What about freezing it? If your freezer was around 0 degrees F, and if you packaged it in small quantities (so you wouldn't have to be accessing the same container repeatedly), that would at least address the temperature issue.

Would freezing hurt it? It could be put in a pan over low heat, and brought to whatever temperature you wanted, fairly quickly.

Just asking.

[RobertCollins]

I place garlic cloves -peeled- in a pan and cover with oil. I bring the temp to 215 degrees F and simmer for about an hour.

Been doing this for a few years and so far so good as the optimist said passing the 10th floor.

I do about a pint at a time and store in a brown wine bottle corked for about a month. I think I'll try a bit with a quarter lemon in it. Who knows, I may like it acidified.

Good thread, thanks.

[OliverB]

once thing I've been wondering now, I store garlic on the counter, and while it usually does not last long, it might sit there (warm, bright) for quite a while. How about botulism developing there? If it's fine to store it like the super market, and if your hands and utensils etc are clean, how can you introduce even the possibility of botulism happening when you just peel it and put it in oil?

I won't risk it, but I'm still wondering.

[andiesenji]

once thing I've been wondering now, I store garlic on the counter, and while it usually does not last long, it might sit there (warm, bright) for quite a while. How about botulism developing there? If it's fine to store it like the super market, and if your hands and utensils etc are clean, how can you introduce even the possibility of botulism happening when you just peel it and put it in oil?

I won't risk it, but I'm still wondering.

←

Raw garlic is exposed to air and even if the pathogen is present, will not develop the toxins. This requires an anerobic or oxygen-free environment. As long as you don't vacuum seal it in a package or container and don't cover it with oil, you can use it with no problems.

I keep raw garlic in a braid, hanging in my pantry, for months. Until it dries out or starts to sprout - then it becomes bitter and I toss it and buy a new braid.

Note that wound botulism occurs in puncture wounds, just the same as tetanus does. It can develop in a puncture wound where one steps on a nail in the garden - doesn't have to be rusty, like for tetanus - which is why any wound like this should be treated by a doctor - usually with hydrogen peroxide, which introduces oxygen deep into the puncture.

Edited July 9, 2009 by andiesenji (log)