We have this issue also, It is getting better, especially over the last couple of years. My son wants everything, even food, to be perfect; but this has lessened as his food tolerances have increased, in general.
We let him pick the bread loaves (slices have to be perfectly square) and bananas (no bruises) It helps b/c he has ownership, and can see that despite the best intentions, food is not going to look perfect.
If social stories work for you, you could try that. Things in nature are not perfect, Things manufactured or assembled by people have flaws. Machine made things have tolerances. etc. This has been an ongoing series of lessons, that take awhile to sink in.
In the short run, you can slice fruits before she sees them. This will not help desensitize, but will help get her fed in the short run when you just have to get it done.