“pre-recorded royalty free loops and samples”
I would propose that these are two separate issues, samples and loops. Leaving aside drum loops from the equation since just about everyone uses them, if you are talking about melodic loops, an instrument playing a melody in a looped audio file then I would say you shouldn’t use it and the company you are submitting to probably is not interested in that type of composition.
If you are talking about samples, like a sample set of a vintage synth, where you have to play/create your own melody using the samples of the synth that the company provided, then you’re just fine.
My personal opinion: Music pieced together from melodic construction kits, like bass lines, guitar melodies and horn lines, that someone else has written should never be entered into a music library as an original composition.
For example, one of our composers creates popular music construction kits that you can download royalty free to help you create your own version of his music
http://www.equinoxsounds.com/dlg/cart/index.php?action=desc&pn=234&c=35&page=8
I would never want to see music created from this construction kit submitted to our library.
Using a construction kit like this and then adding a guitar solo or sax solo on top does not make this your music, in my opinion, even though it is considered royalty free.
I’m not sure how apple loops and garageband work though. Maybe they don’t have loopable melodies.
And again, these are just my opinions.
-Mark