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How on earth is not washing a cast iron with soap not harmful? Since even if you wash it good with hot water and Salt, wouldn't there still be a possibility of harmful bacteria and such left in the crevices in the metal? I mean the metal is porous, correct?

Also same goes for the seasoning we use (bacon grease, oil, etc) How does this not get a bunch of bacteria on it?

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Sorry, but these are lots of different questions. The main has to be closed, as it is about health, which is off-topic (see the faq). I will remove it and subsume the part about food safety into a single question. If you are still interested in the practice of maintenance-seasoning with spray oil, you should ask a separate question. –  rumtscho Mar 19 '13 at 10:55
    
Related: cooking.stackexchange.com/questions/21104/… –  Jefromi Mar 19 '13 at 14:06

3 Answers 3

up vote 6 down vote accepted

Toxic?

Neither the seasoning (which is essentially polymerized fat) nor the rust (which is... rust) is harmful in small quantities. Of course, I would not eat either by the spoonful.

Spray oil as seasoning fat?

See the many questions on seasoning, but cooking spray is far from ideal as a seasoning fat, as it contains emulsifiers and such, and tends to be a poly-unsaturated fat (that is, liquid at room temperature). Saturated fats are better. One of the most common household options is, dare I say it, Crisco. Or bacon fat.

Why is scrubbing with salt sanitary?

Tradition is that cast iron is not washed with soap and water. The purists will rail at me for saying this, but an occasional light wash with mild dish soap is not going to irreparably harm your seasoning. As you cook, it is continually being rebuilt, at least in frying which is what cast iron pans are best for.

Nonetheless, the common method of just cleaning out with salt and then drying leaves a dry surface, which is not hospitable to bacteria or other pathogens. They cannot grow in a desert. Even if there are micro-crevices in the pan (there are), they would either be filled with the seasoning layer and irrelevant, or leaving the bacteria in direct contact with that active iron surface, which is also not good for them. But the main issue is that the pan is dry.

Finally, since the pan is hot when being used (often even preheated in many applications) any tiny amount of bacteria which find a foothold will normally be killed quite early in the cooking process.

The seasoning—even from delicious bacon fat—that forms the protective layer on the pan is also polymerized, which makes it less available as a food source for bacteria, even if they could otherwise grow in the very dry environment of a properly cleaned and dried cast iron pan.

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Do you think that A towel dry + a crisco rub (or oil whatever rub) is ok after cooking/cleaning? (Like after I scrub it with salt+hot water). Or do I "NEED" to Bake it after I clean it? Or can I just towel dry it very well then oil rub it down? (Assuming it's not dripping with oil of course) –  Mercfh Mar 19 '13 at 2:04
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I will let people who use cast iron more than I do answer about their direct experiences... but remember, one of the reasons for the heated drying is to prevent rust. Iron likes to rust in the presence of water. It throws little rusting parties with little oxide party favors. Those micro-crevasses on the outside of your pan, with water from washing still in them after the towel dry are little rust party halls. –  SAJ14SAJ Mar 19 '13 at 2:06
    
@Mercfh you can towel dry it, or you can just put it over medium heat stovetop for a few minutes (I find throwing it on the stovetop easier...). Either way, as long as its dry. Once it has some seasoning built up on it, you don't need to keep putting oil on it to store it (put some on it when heating it for use, though, which you're probably doing anyway). Just don't store it somewhere damp. –  derobert Mar 19 '13 at 16:00
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And actually, flaxseed or (second best) soy are good choices for seasoning. And soy is very cheap. (Both are better than PAM, which is generally canola + lecithin). Google for the Sheryl Cantor blog posts, or check Cooks Illustrated's testing of it. Flaxseed oil seasoning will survive the dishwasher, soy oil mostly does. [Though if you kept doing that, I'm sure it'd ruin the seasoning soon enough.] –  derobert Mar 19 '13 at 16:06
    
@derobert This is true, but for a new cook, I was recommending oils that would be likely to be on hand in the US kitchen. –  SAJ14SAJ Mar 19 '13 at 22:58

Every time cast iron cookware is used at boiling or frying temperatures, it is so hot that any bacteria or viruses on the surface are destroyed. Other than removal of gross contamination by scraping, followed by wiping with a paper towel or dry rag, no further sanitation is needed. If meats or salty foods have been cooked in a skillet, it can cause sticking. Rinse with hot water, or a small amount of hot water can be brought to a boil in the skillet to dissolve the salt. Dry the skillet and coat lightly with vegetable oil to inhibit rusting.

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I have used Cast Iron all my cooking life. A well seasoned cast iron product should not rust, but on the off chance it does. Take a wire brush to the rust until you get to the fresh iron again. Then seal it with some oil.

You should never really use soap on cast iron because it strips the oil that is protecting it. But if you do, it is best to reapply some oil to the surface and heat it to help it bind to the cast iron. I just wash it, then re-coat mine with a little oil on a paper towel and heat it on the stove top for a couple of minutes then let it cool down before putting away.

Salt works as a good way to clean cast iron since it is abrasive enough to scour away whatever is sticking but not harm the "seasoning" of the cast iron.

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