Yes, it can be sanitary to not use soap on cast iron, as long as the skillet is properly seasoned and maintained. The key to keeping a cast iron skillet clean and safe for cooking is the build-up of a natural non-stick coating called "seasoning." Seasoning is formed by repeatedly applying and polymerizing oil on the skillet's surface, creating a protective layer that prevents rust and provides a non-stick cooking surface.
Using soap on cast iron can strip away this seasoning, exposing the iron surface and potentially leading to rust formation. However, if the skillet is seasoned properly, it forms a stable and protective barrier that resists bacterial growth and keeps the cooking surface safe.
Here's how to clean and maintain a seasoned cast iron skillet without using soap:
Immediate cleaning after use: After cooking with your cast iron skillet, immediately clean it while it's still warm. Use a soft brush or a non-metal scrubber to remove any food residue or stuck-on bits.
Rinse with hot water: Rinse the skillet with hot water to remove any remaining debris. Avoid using cold water as the rapid temperature change could cause the cast iron to crack.
Dry thoroughly: Thoroughly dry the skillet with a clean towel to prevent moisture from causing rust.
Re-season when needed: With regular use, the seasoning on the skillet may wear off over time. When you notice the skillet becoming less non-stick or starting to rust, it's time to re-season it.
Avoid cooking highly acidic foods: While a well-seasoned cast iron skillet can handle acidic foods in moderation, it's best to avoid cooking highly acidic dishes for an extended period, as they can potentially break down the seasoning.
Cook regularly: Regular use of the skillet helps maintain and build up the seasoning, making it more non-stick and enhancing its overall performance.
If you're concerned about sanitation, it's essential to ensure that your cast iron skillet is properly seasoned and free from rust. The high heat used in cooking with cast iron also helps kill off most bacteria and pathogens.
That being said, if you're dealing with raw meat, particularly poultry, or any other potentially harmful bacteria, you might consider using a mild soap and water to clean the skillet. In such cases, immediately dry the skillet and promptly re-season it to restore its protective coating.
In summary, as long as your cast iron skillet is well-seasoned, properly maintained, and used for regular cooking, not using soap for routine cleaning should not pose any sanitation issues. However, there might be situations where using soap is prudent, especially when dealing with potential sources of harmful bacteria.