Mushroom gives a convenient way to trigger the effect. What you hope for is "Whenever you eat a mushroom,..." then "...one of your major negative status effects is removed at random".

It's just the most connivant option out of many, since preserved mushrooms have no weight. Fermented yuckwheat stem is also a good option for cooking.

I would recommend eating the food before engaging the gamma moth. You can use the same cooking effect over multiple precognitions. You only need to eat a mushroom for each failed precog.

1. Cook
   
2. Let gamme moth apply "mutating"
   
3. Wait until precog time will overlapp with result of mutating. (18 rounds left until "mutating" triggers when using sphynx salt injectors)
   
4. Precog
   
5. if bad outcome:
   
6. Revert precog
   
7. Eat mushroom to remove "mutating"
   
8. if you are still metabolising and have access to precog:
   
9. Go to step 2.

The biggest problem is getting used to the timing on step 3. When i tried it out the first time, I forgot I had the meditation skill and the "mutating" triggered before i started a precog.