Is this true or shtuyot?
From Star-K:
https://www.star-k.org/articles/articles/1106/the-spice-of-life-a-kashrus-overview-of-salt-pepper/
“Today most table salt contains this nutrient in the form of potassium iodide. Potassium iodide, however, tends to degrade in the presence of moisture; in order to protect the iodine, a small amount of dextrose often is added to the salt to prevent oxidation. While not generally a kashrus concern, dextrose is derived from corn (and sometimes, wheat) starch, and therefore poses an issue for Passover use. It is for this reason that we purchase non-iodized salt for Passover. Ironically, it is the preservative – and not the iodine itself – that poses the problem.”
Must salt have hashgahah for pesah or be non-iodized?