Botulism concerns re infused oils and confit

[Lisa Shock]

Today, The Minimalist column by Mark Bittman extols the joys of homemade flavor-infused oils, without regard to the food safety issues inherent in taking foods known to carry C botulinum spores and placing them in the low-acid, anaerobic environments in which they thrive.

Do they not have fact-checkers or nutritionists or someone check these articles? This is a basic issue covered in the ServSafe exam, and in health code requirements in most US states.

HERE is a link to more detailed info, written by scientists.

[lala]

Doesn't surprise me, I never cared for his column anyway. If people follow the directions and get sick, will they sue?

[Lisa Shock]

Doesn't surprise me, I never cared for his column anyway. If people follow the directions and get sick, will they sue?

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They could. There are only a few situations where you can't sue someone in the US.

[prasantrin]

In fairness, the recipe uses the "safer" method which involves heating the aromatics in the oil, then cooling, bottling, and refrigerating it. He says the oil is usable for one month or so, which is longer than FDA guidelines of 10-14 days, but the FDA often rules on the side of overly safe (the FDA used to say pork should be cooked to 170F which results in dry, unpalatable pork, but has more recently given a lower end of 160F which is a bit more appetizing).

That still doesn't make his method perfectly safe, but it's not as quite as egregious as made out to be, in my opinion.

[Fat Guy]

As I understand it, botulism is primarily a concern if you infuse with raw product and store at room temperature. Bittman's recipe calls for cooking followed by refrigeration and recommends using within a month.

[Lisa Shock]

Botulism spores are heat resistant. And, several of the deadly strains grow at refrigeration temperatures. That's why it is of such great concern.

Garlic in particular is known to carry a large number of the spores, and keeping any garlic, cooked or not, in a low acid, anaerobic environment ins dangerous.

There have been outbreaks involving cooked garlic oil, and roasted garlic infused oil. These cases were part of the FDA's banning garlic oil infusions, except those produced with an acid from the beginning of the process.

[sickchangeup]

Botulism spores are heat resistant. And, several of the deadly strains grow at refrigeration temperatures. That's why it is of such great concern.

Garlic in particular is known to carry a large number of the spores, and keeping any garlic, cooked or not, in a low acid, anaerobic environment ins dangerous.

There have been outbreaks involving cooked garlic oil, and roasted garlic infused oil. These cases were part of the FDA's banning garlic oil infusions, except those produced with an acid from the beginning of the process.

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Letter to the editor?

[David A. Goldfarb]

If there's no link to comment on the article or the recipe, they usually show up on his blog by the next day or so at http://bitten.blogs.nytimes.com/

[Lisa Shock]

I wound up sending email to Bittman. So far, just got an auto-reply. The blog only has a video version of his recipe and no place to comment upon it.

BTW, to be precise about the heat issue, the spores can live up to five hours in boiling water. I didn't see Bittman take the oil that hot or cook it for that long. You can kill it in a pressure canner that is at 250° F for more than 5 minutes. But, again, I didn't see a pressure canner used in the video or read about using one in the article.

[rlibkind]

the Times has corrected the earlier on-line story in Wednesday's food section (and the on-line version), as follows:

A recipe on Page 4 today with the Minimalist column, about infused oils, corrects two errors that appeared in the recipe when it was published at nytimes.com on Friday, Saturday and Sunday. The online recipe misstated the amount of time the oil should cook after it bubbles and the length of time it is safe to use after being refrigerated. The oil should be cooked five minutes, not “a minute or two,” and it should be kept in the refrigerator no more than a week, not “a month or so.” The corrected version can also be found at nytimes.com/dining.

[Lisa Shock]

Wow, maybe they did read my email.

Of course I also gave a personal injury lawyer buddy of mine a heads-up too...

[lala]

I'm sure many people wrote in, I certainly did. It was good to see the correction.

Fat Guy, both the garlic and fresh herbs cited are problematic in infused oils that are to be stored. That's basic food sanitation, taught early on at the CIA, and as Lisa pointed out, on the SafeServe test. Best practice is to make infused oils fresh daily and not store more than a day or two in the fridge.

[rlibkind]

The video accompanying the article on the Times' web site includes a superimposed "correction" when Bittman says it can be stored for a month, and another emandation clarifying cooking time.

[Magictofu]

I thought that since oil heats up at a far higher temperature than water (temperatures much higher than in a pressure canner) even the most resistant bacteria would be killed by the process. Is the issue mostly about the short cooking time?

[MaxH]

I thought that since oil heats up at a far higher temperature than water  (temperatures much higher than in a pressure canner) even the most resistant bacteria would be killed by the process.

I haven't read the article, but the problem is more subtle. If any water remains in the flavoring component (garlic etc.), that will self-limit its local temperature to water's boiling point (212 F) which won't reliably kill C. bototulinum spores even with hours of cooking. It's for this reason that commercial canning uses pressure cookers: pressure raises water's BP permitting water-bearing foods (which is most foods) to get hot enough to kill the tough spores. As others have said, garlic in oil is a classic hazard, it's cited in US and international botlism-prevention advisories.

Same hazard lurks, unpublicized, in currently fashionable confit recipes. Historically, meats like duck to be cooked and preserved in fat at room temp. were first very strongly salted, often including saltpeter -- chemical preservation, which can inhibit Claustridia growth even with spores present. Today, many meat confit recipes are salted for flavor, not preservation. The meat's then cooked at normal pressure and stored anaerobically under fat -- conditions permitting C. bot growth which, over time, produces deadly toxin. Commercial fresh confits today come with instructions to use soon or freeze (also inhibiting organism growth). The toxin itself is fragile and killed by brief cooking (a safety factor in uses like cassoulets). Big risk is if a fresh confit is stored for more than a few days at room or even refrigerator temp. (one or two of the four major C. bot strains grow at refrigerator temps), then eaten or "sampled" without further cooking. I've seen online confit recipes and discussions describing room temp. storage for months. A public-health time bomb.

On one popular food Web site, warnings about this (citing FDA/NIH/WHO guidelines)evoked a skeptic's reply that there's no cause for concern unless the poisoning is demonstrated (?!). By the way, even this food Web site has carried reckless advice to take Acetaminophen (a drug lately in the news) when you have a partially impaired liver!

[TimmDavis]

I thought that since oil heats up at a far higher temperature than water  (temperatures much higher than in a pressure canner) even the most resistant bacteria would be killed by the process.

I haven't read the article, but the problem is more subtle. If any water remains in the flavoring component (garlic etc.), that will self-limit its local temperature to water's boiling point (212 F) which won't reliably kill C. bototulinum spores even with hours of cooking. It's for this reason that commercial canning uses pressure cookers: pressure raises water's BP permitting water-bearing foods (which is most foods) to get hot enough to kill the tough spores. As others have said, garlic in oil is a classic hazard, it's cited in US and international botlism-prevention advisories.

Same hazard lurks, unpublicized, in currently fashionable confit recipes. Historically, meats like duck to be cooked and preserved in fat at room temp. were first very strongly salted, often including saltpeter -- chemical preservation, which can inhibit Claustridia growth even with spores present. Today, many meat confit recipes are salted for flavor, not preservation. The meat's then cooked at normal pressure and stored anaerobically under fat -- conditions permitting C. bot growth which, over time, produces deadly toxin. Commercial fresh confits today come with instructions to use soon or freeze (also inhibiting organism growth). The toxin itself is fragile and killed by brief cooking (a safety factor in uses like cassoulets). Big risk is if a fresh confit is stored for more than a few days at room or even refrigerator temp. (one or two of the four major C. bot strains grow at refrigerator temps), then eaten or "sampled" without further cooking. I've seen online confit recipes and discussions describing room temp. storage for months. A public-health time bomb.

On one popular food Web site, warnings about this (citing FDA/NIH/WHO guidelines)evoked a skeptic's reply that there's no cause for concern unless the poisoning is demonstrated (?!). By the way, even this food Web site has carried reckless advice to take Acetaminophen (a drug lately in the news) when you have a partially impaired liver!

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I'm not sure what Duck Confit recipes your coming across, but all the ones I've use or shown, the salt is used for both preservation and flavor. And mostly for preservation.

[MaxH]

I'm not sure what Duck Confit recipes your coming across, but all the ones I've use or shown, the salt is used for both preservation and flavor. And mostly for preservation.

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Timm, I researched the subject in some depth a while ago, viewed a range of online confit recipes, and consequently took that point for granted above. Certainly my caution is not intended for the older French recipes I have (in the standard early-1900s reference cookbooks), or any similar ones, designed properly for long unrefrigerated storage. An earlier summary below gives sources. If you want to correct Harold McGee, I can put you in touch, he's local to me; but I've seen modern recipes myself that support his point, using quantitatively far lighter salting than the originals (whether or not they characterize this with the vague term "preservation" -- any degree of salting can be said to help preserve meats, after all). I've also seen modern recipes for non-poultry and non-meat confits, cooked and preserved in fat, with very little salt at all. Without all of that, I would never have posted above.

Current popularity of poultry confits has sometimes dangerously obscured the fact that originally, like other meats preserved for unrefrigerated storage, they were very highly salted, often with nitrite or nitrate preservatives ("saltpeter"). A detailed French recipe in the old Larousse Gastronomique begins by steeping a cut-up goose in a kilogram (two pounds) of mixed salt and saltpeter, and claims indefinite shelf life for the result. In sharp contrast, as Harold McGee explains [On Food and Cooking], most modern non-canned meat confits are made to be eaten within a few days, therefore salted much more mildly, for flavor and color, not preservation. This "few days" also coincides with published guidance on other foods subject to anaerobic bacteria.

[Lisa Shock]

MaxH, thank you so much for posting this information!

[Lisa Shock]

Today's Recipe Redux, in the Times Magazine is Brandied Peaches and the article incorrectly states that old canning methods, where air pockets remained in low-acid sugared fruit, harbored botulism and implies that the current author's water-bath canning procedure will eliminate the threat. Um, wrong and wrong.

They really need an educated editor over there....

[Lisa Shock]

The time limit to edit posts is past, so sorry about the double post.

I just wanted to add that I recognize that peaches aren't normally a huge source of botulism spores, unlike garlic, so there is less of a concern when preserving them.

[Lisa Shock]

I just saw Sandra Lee making garlic oil without acidulation or heat, and recommending keeping it for up to two months in the fridge on her Money Saving Meals show. Maybe she should have paid better attention in class at the Cordon Bleu -and of course some one at the Food Network should be checking these recipes for safety.

[Cim Ryan]

Given that the smoke point of olive oil is higher than 250F, why not "pressure can" an infusion to sterilize it?

[MaxH]

Given that the smoke point of olive oil is higher than 250F, why not "pressure can" an infusion to sterilize it?

Cim, I'm not quite sure what you mean by "pressure can," but if (unlike most home cooks) you have a pressure cooking system that reliably meets the recommended guidelines then you certainly can kill off Claustridia spores. That's what commercial canners are required to do. One of the notorious US botulism outbreaks (Bon Vivant soup co.) happened when equipment malfunctioned and failed to sterilize canned Vichysoisse (potato-leek) soup, meant to be served cold, without further cooking.

Fat smoke points are all safely above the required temperature. A dangerous misconception (surfacing in some past eGullet postings, and almost any other forum addressing this) is that heating fats to 250F or higher also heats the foods in the fats to the same temperature. You'll find no chemists and few physicists with that notion. They know that if the foods contain any water (as they always do, in these situations) it limits the local temp. in the food to only 212F, and very efficiently too, thanks to Lvap (latent heat of vaporization). Same physical effect that demands much more energy to boil away a quantity of water than to heat it to the boiling point; same effect that makes evaporative cooling work, and various other things we take for granted.

The whole point of pressure is to raise water's boiling point high enough that everything in the food can get above 250F, water and all.

Edited September 21, 2009 by MaxH (log)

[Lisa Shock]

That would seem to work, however, most health department guidelines for professionally producing such a product (where it's allowed at all) also require acidulation of the garlic as the first step. One quick note is that even under pressure canning conditions, the product would have to fully reach temperature and stay there for more than 5 minutes.

You may have noticed that there isn't much garlic oil for sale in supermarkets.

[MexChef]

So, does anyone have a suggestion of how to safely make garlic oil, without cooking it?