The Truth About Cast Iron

paintflinger · Mar 27, 2015

Haggises said:
The point of using soap is to wash off the fat that the bacteria can lodge in. Not to slide the bacteria off.
Not sure what's hard to understand about this.

Fair enough. However, you're never going to wash off all of the fat and grease.

Kit Walker said:
Detergents break down the grease and fats so that they can be washed away from the surface. There would be little point in using them if they didn't.

Also, a layer of grease can create an anaerobic environment.

Like I said above, you're never going to fully wash off all the fat and grease. Again, please show me bacteria that can thrive in an open environment, can produce enough of a concentration of toxins, and won't be killed by simply heating the pan.

Only information I've found is the following and non of it is likely to be in your home, especially if you keep it clean and follow good food prep safety:

Seems almost every question about bacteria seems to bring about both the bacteriophobes and the cavalier. In this case, the cavalier are probably closer to being right, but I'll try to present the facts so that you can decide for yourself.
The most common microbe groups responsible for household food poisoning are:

Salmonella, found in poultry, produces the CdtB toxin. CDT can be denatured (technically, "heat-labile") but is one of the most resistant toxins, taking 30 minutes at 70° C to destroy. This type of bacteria isn't normally associated with eggs, but since chicken eggs and other poultry products may be handled in the same area, it's not unthinkable that the shells could become contaminated - and depending on how you handle the eggs, so could the frying pan.

E.Coli is normally associated with beef but is also known to be found on egg shells. It's improbable, but not impossible for it to be found in yolks as well. This is a bit of a weird one because egg yolks also have immunization properties against e.coli, but not in the yolk itself or the frying pan. The strains of e.coli associated with food poisoning encode Shiga-Like Toxin (SLT) and also Enterotoxins, the latter of which are often heat stable. I'm not sure about SLT, but the STs can withstand boiling for 30 minutes.

Campylobacter (causing Campylobacteriosis) produces certain enterotoxins and also CDT. As above, these tend to be heat-resistant.

C.botulinum is responsible for for botulism and is ubiquitous. The spores are incredibly difficult to kill but they are also only harmful to infants and the immunodepressed. More importantly, the bacteria are killed by heating to 85° C for 5 minutes and are also anaerobic - meaning they can only grow when they are not exposed to air. In other words, these may be present, but won't grow and produce toxins on a reasonably clean pan.

C.perfringens is one of the most common sources of food poisoning, and I believe is actually what drives a lot of the specific food safety/food inspection rules. The spores are very heat resistant (can survive boiling for a full hour), and even though it is anaerobic, it is also aerotolerant. It can grow on a pan - just more slowly than it would grow in an enclosed container or in raw/fresh food.

S.Aureus causes staph infections but also produces heat-resistant enterotoxins. It doesn't generally come from food, but more than 20% of humans are carriers, and also many pets (cats and dogs), so it is very likely in your household somewhere and can easily get on your frying pan and multiply on leftover food bits.

B.cereus is less common but very resilient (they're known for "fried rice syndrome" because they can survive steaming) and afterward produce spores and heat-resistant enterotoxins. Important to note that many strains of this are harmless - but not all.

V.cholerae causes (as you may have guessed) cholera symptoms which come from CTX and TCP toxins. Both of these are heat-labile although I wasn't able to find a time/temperature data point.

Chances are, you have at least one these friends in your kitchen. Chances are, you have several. The question is, did enough of them manage to get onto your frying pan after your last meal to produce dangerous levels of toxins?
Probably not. It's really very unlikely. But it is possible, and you're taking a chance if you don't wash your dishes.
In fact, it's probably more dangerous with eggs, because typically you'd cook eggs only up to a temperature of around 70° C, at most (63° is the temperature at which they set). So day after day you're bringing all those lovely bacteria right into the danger zone for several minutes and not staying above it for very long at all!
Doing this one time... really not a big deal. Bacteria don't get to multiply much in the 5 minutes (or less) it takes to fry an egg, and most eggs aren't even contaminated to begin with, although there have been small outbreaks.
But doing this several times, day after day - you're increasing your risk each day because the pan may never get hot enough, long enough, to kill all of the new bacteria from the day before.
I would strongly recommend that you wash your pans after use. You don't need to use soap if they're cast-iron; a good scrub with salt and hot water is fine. But please - especially if you're going to be cooking for guests - don't just leave the dirty pans sitting there and use them again the next day without washing them first. It's not safe.

P.S. I'd like to draw attention to the fact that of all of the items in the list above, botulism, despite having some of the worst symptoms, is generally the least of your worries. Both the bacteria and the toxin are easy to kill, and the spores are harmless to healthy adults. So if you hear people on this site or any site talk about food safety entirely in terms of botulism and the temperatures required to kill/inactivate the bacteria/toxin, ignore them, because they haven't done their homework.

A layer of grease wouldn't provide enough of an environment to build up enough toxins.

As I stated earlier, if it makes you feel better to use soap, then do so. Washing off unused fat and grease certainly makes sense if you're worried about any rancid flavors. It just doesn't make sense to give all the credit to the soap/detergent, when the heat is going to garner you far more safety. That and making sure your food is uncontaminated.

For me, cleaning the pan involves heating it up till its smoking and then adding tap water to it so it flashes to steam / boils and pulls anything off the surface. Quick method for cleaning. Throw it back on the heat with some oil and heat till smoking again. Et fini. Big note here is that I'm applying enough heat and for enough time that it kills anything that might be on there. I'm also not waiting to clean it.

Also, I'm surprised no one has gone into the leeching of iron from cast iron pans.

Donnchadh_Sempill · Mar 27, 2015

For me, I allow the skillet to cool, then wash it thoroughly with hot, clean water. I then dry the pan with a towel, and toss it in the oven at 250-300 for 15 minutes. I then coat it with oil/shortening while still hot. Lodge Manufacturing recommends that you leave out the soap. They've been in the business for A LOT of years--and have A LOT to lose if the advice is bad.

beginish · Mar 27, 2015

I appreciate all of the views on cleaning, food poisoning and toxins. Let's just leave that with the idea that everyone should clean their pans in whatever fashion they want, for whatever reason they want. It's not like getting germs from used razors.

I kid, I kid.

thematthatter · Mar 27, 2015

paintflinger said:
Fair enough. However, you're never going to wash off all of the fat and grease.

Like I said above, you're never going to fully wash off all the fat and grease. Again, please show me bacteria that can thrive in an open environment, can produce enough of a concentration of toxins, and won't be killed by simply heating the pan.

Only information I've found is the following and non of it is likely to be in your home, especially if you keep it clean and follow good food prep safety:

A layer of grease wouldn't provide enough of an environment to build up enough toxins.

As I stated earlier, if it makes you feel better to use soap, then do so. Washing off unused fat and grease certainly makes sense if you're worried about any rancid flavors. It just doesn't make sense to give all the credit to the soap/detergent, when the heat is going to garner you far more safety. That and making sure your food is uncontaminated.

For me, cleaning the pan involves heating it up till its smoking and then adding tap water to it so it flashes to steam / boils and pulls anything off the surface. Quick method for cleaning. Throw it back on the heat with some oil and heat till smoking again. Et fini. Big note here is that I'm applying enough heat and for enough time that it kills anything that might be on there. I'm also not waiting to clean it.

Also, I'm surprised no one has gone into the leeching of iron from cast iron pans.

1. Cook chicken to 165F, Pink is not an indicator of doneness.
2. that's generally associated with feces, just assume that E. coli is everywhere.
3. I dont know enough about Camplobacter except that lysol kills it.
4. not really something you need to worry about unless your canning your cast iron pot.
6. lives in your nose in about 20% of the population at any one time. Also causes acne and boils. Washing your hands will prevent this. Time is needed for the heat stable toxins to develop.
7. A part of your natural flora of your skin. No amount of scrubbing will get rid of it, opportunistic infection.
8. we are overdue for a cholera outbreak.

basically if you want to prevent food borne illness, proper hygiene, proper food storage temperature (under 39F in fridge or over 140F for hot holding not to exceed 4 hrs) and proper cooking will prevent the majority of food problems. 145F for pork, beef and fish/165F for leftovers, ground meats and chickens.

Google the acronym FATTOM, Food, acidity, time, temperature, oxygen and moisture.

A dry clean cast iron pan, in my opinion does not provide the environment to foster bacteria growth. If it did we would be storing cast iron in the fridge or freezer.

Alacrity59 · Mar 27, 2015

Kit Walker said:
Botulism is only one example, an example that I gather you missed. It's not the spores that kill you in this situation. It's the toxins that they produced BEFORE you killed them that will do so.

Insofar as soap damaging the seasoning, SOME modern soaps may, but none of the ones I've ever used have done so. The soaps used in your great grandmother's time that contained lye certainly did. However, a blanket condemnation of all soaps is merely another urban legend, backed by superstition.

YetiDave said:
The spores have to develop into bacteria first, which they can't do in the presence of oxygen. It's the bacteria that produce the toxin it's extremely rare and I can't conceive of a situation in which it would happen on an iron pan. Just sayin' that botulism is not an issue at all when it comes to your chosen method of cleaning cast iron

Kit Walker said:
What part of ONE EXAMPLE don't you understand?

Kit Walker said:
Detergents break down the grease and fats so that they can be washed away from the surface. There would be little point in using them if they didn't.

Also, a layer of grease can create an anaerobic environment.

You do paint a grim picture. I'm hoping most of us don't have a great big layer of grease sitting in our cast iron pans between meals. I think when we use our pans they are plenty hot. Hot enough to kill most anything that is going to do us damage. I tend to test mine with a few drops of water . . . that is at least boiling point. I put some olive oil in and it smokes a bit . . . that is somewhere around 320 F. An autoclave runs at about 250 F if I recall and this is what is used for surgical instruments.

I'm not saying there is no danger . . . just that if there is any danger it has got to be extremely rare.

Have there been actual cases of folk dying from not using detergent on their cast iron. . . . or for that matter not cleaning their BBQ grill with detergent between uses?

morgantruce · Mar 27, 2015

I had no idea that my frying pan was conspiring to do me in.

Legion · Mar 28, 2015

morgantruce said:
I had no idea that my frying pan was conspiring to do me in.

Frying pans don't kill people. Angry women swinging frying pans kill people.

A frying pan is perfectly safe in the hands of someone with proper experience and training in frypan use.

Lmarkow · Mar 28, 2015

This thread now belongs in the Honing forum. Lol

morgantruce · Mar 28, 2015

CHICAGO (FOX 32 News) - An Elgin woman charged with murder after allegedly hitting her boyfriend in the head with a frying pan during an argument was ordered held on $750,000 bond Monday.
Nora P. Peterson, 34, allegedly hit her live-in boyfriend Michael N. Mielczarek during an argument Saturday at their apartment in the 100 block of South State Street, according to Elgin police.
She allegedly hit him in the head with several items, including a frying pan, causing the 55-year-old man to fall and hit his head on the floor, according to a release from police.
A judge ordered Peterson held on $750,000 bond at a Tuesday morning hearing. She is being held in the Kane County Jail and will next appear in court Aug. 29.
Officers responded at 3:47 p.m. Saturday after he stopped breathing and Peterson called 911 for an ambulance, the release said. Paramedics took him to Provena Saint Joseph Hospital in Elgin, where he was pronounced dead.
Police would not comment Monday night on what sparked the fight.
An autopsy Monday found Mielczarek died of blunt force trauma to the head, the release said.
The autopsy showed he had three head wounds -- at least one that likely came from the frying pan, and one from hitting the floor, police said.

Haggises · Mar 29, 2015

NOW it belongs in the honing forum.
Wonder if that couple had the oil or water discussion...

Alacrity59 · Mar 29, 2015

More of a Clownhouse thread now.

I think Mess Hall wise we are done here. This thread is closed.

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The Truth About Cast Iron

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Haggises

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