"Quality Issues"

Your cutout work is not precise enough, you need to train your skill in that task: 

I just shortly looked into that file, without doing my usual tests, and I saw those errors immediatly. 

Taking the images to Photoshop, and laying a red line around the cutout shows very easily where you have cutout defects:

You have here multiple errors: aliasing (arrow), rendering inconsistencies and cutout errors. As the plate is a geometric form, you should have cut out the plate geometricly, without considering the greens. After that, you recreate the mask at the greens. That gives you the needed sharp corners, where the leaves get over the plate's border. It also makes sure that the plate is correctly cut out. You have, by accident, cut off part of the plate.

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Coming back to your steak asset, a blue line exposes errors in the cutout. Those blue points show transparency, where no transparency should be. The blured line shows that your cutout is too soft, checking at high magnification (without the line effect) shows a ghost line around the flesh. 

This will cause major issues with the asset, when a buyer decides to get a drop shadow, or use a non-white background. They won't be happy, as they will need to pass hours of correcting your asset.

Whith the blue line, you see immediately where errors are to be found. Those are easy corrections during the cutout work, as you only need to paint over the mask to get rid of those holes. I suppose that you used some automatic masking to start with. I avoid that, whenever I can.

I'll discuss one specifically; however, generally speaking, the rest lack a sense of actual photorealism and have a "plastic" quality about them. Improved irises with facial restoration software and some editing.