I created a roast

I got a shchiekcemn and I decided to create a roast. I gave it to a co-worker. After some time, she told me I messed up.

Here are the clues what's with the roast:

1. Fire, Black, Destroy
2. Poison, Salmonella, Disgust
3. Gravy, Mayonnaise, Butter

So why did she claim I ruined it?

H1:

L1 & L3 has to deal with the preparation, whilst L2 is how my friend thought of it.

H2:

They all have similarities, all of which are negative. Whatever the case, the roast itself is negative. It was claimed it is inevitable, inedible, terrible.

• L = List, H = Hint. Note that.
– user73834
Mar 22 at 9:45
• I don't really understand how this puzzle works. It looks as though you burned it and added a weird sauce... and your friend thought it tasted terrible. I'm not sure what the puzzle itself is, because there are no obvious rules to begin solving it... or any idea what form the solution is meant to take. Mar 26 at 6:00
• @Graylocke If you mean L3, then no, it wasn't a sauce. Just to figure out the puzzle, you have to identify the clues, and figure out the reasons of the roast being ruined.
– user73834
Mar 26 at 6:24

This is probably wrong, but I've learned that

1. Occasionally the 'probably wrong' answer is actually right, and
So here goes:

The Preparation:
FIRE, BLACK, DESTROY

These are all synonyms for 'break/remove/separate'

GRAVY, MAYONNAISE, BUTTER

These are all things you 'spread'

The main roast:
POISON, SALMONELLA, DISGUST

These are all things which are 'bad or terrible'; in fact, awful

So what happens if we take the main roast, and

break it apart and spread it out?

We get:

A W F U L, or if you slur your speech, "a wuful", that is, "a waffle"

Why was it messed up?

I suppose because you roasted it? Don't roast waffles. They should go in a toaster.

Why was it 'inevitable, inedible, terrible', and negative?

Inevitable means 'absolutely certain'. Whereas to waffle is to be absolutely uncertain. This is the exact opposite, or negative/inverse meaning.
Inedible is what you get when you roast a waffle. That'd be a pretty negative experience.
Terrible means 'awful'. A word with negative connotations which has been addressed already, perhaps reiterated here as a hint.

As for 'shchiekcemn', what is that?

That one is easy. It's the Rot13 of 'fupuvrxprza' ; )

So in conclusion:

Don't roast waffles. Or else find the actual answer to this puzzle. : )