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Mar 20, 2013 06:23 PM

White spots appearing on sweet potatoes [right before my eyes! ] . . .

I know I must appear frightened by sweet potatoes but this really freaked me out:

I cut into this sweet potato and a few seconds later, these crazy white spots appeared. I cut another wedge off and the same thing happened. If I moved my finger across the spots, they absorbed back into the sweet potato . I ended up cutting 1" wedges, and washed the white stuff off, and nuked them and tasted fine.

What the heck is this stuff? Is it safe to eat? (BTW, these were organic sweet potatoes from Whole Foods).

Ironically, they appear similar to the white spots on the purple sweet potato I purchased at the asian grocery (shown here:



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    1. Can't say I've ever encountered that before, but as long as the white spots didn't grow fuzz on them, I'd say it's veggie sap. Were it me, I'd have done what you did, wash them off and go for it. How do you feel?? How's your stomach? If you're still breathing and feel okay, I wouldn't worry about it (also, I wouldn't spend alot of time looking at it ...). How was dinner??

      1. That's not uncommon. It's a milky white starch in the sweet potato, sometimes called white ooze. Yes, also called sap.

        More info here:

        2 Replies
        1. re: maria lorraine

          Thanks for the link, that's very reassuring.

          Having recently seen "Attack of the Killer Tomato", I guess I let my imagination run away with me!


          1. re: mike2401

            Attack of the White Ooze. Appearing Before Your Very Eyes.
            Playing in a kitchen near you.

        2. not ironic at all....same type of vegetable, same type of substance.

          Completely harmless - it's just part of the sweet potato.

          1. Whew good to know! I've never seen this and almost ruined my dinner:)