I just had this issue come up and what I did was a little weird but it worked.
I had my herring and anchovies in a wet brine for 2 days (rock salt, Mrs. Stewart's). I pulled the bait out of the brine, laid them on paper towels to dry them out a bit then put them in a zip lock bag with a cup or borax, a tablespoon of baking soda and about 1/4 cup pickling salt.
I rolled the bait (GENTLY) in this mix and placed the bait back in the freezer.
The bait looked AWESOME! Super shiny, and firm! I was able to fish this bait over 3 weeks worth of trips. After I got home, I put the bait back in the freezer.
I am currently curing up red labeled herring to try this mix again. What's great is, because of the borax, salt and baking soda, the bait keeps really well even when not on ice. I mean, I put it on ice but it really preserves the bait. I will post a picture when I get this batch all finished up.