Por que han sido rechazadas mis fotos?

Next time just post the header of the refusal: "Quality Issues". The text is always the sane and not important. The mechanical translation is quite good, but multiple languages may confuse the system, so it's best to stay in one language. 

As checking assets takes time, you should limit yourself to one to three assets and then check, if you can check the reminder by yourself. You can always post a new request, if the solutions offered for one asset do not fit a different one.

This said, I checked 2086:

You clearly see the high noise level, when checked at 100%. You used ISO 1000, so you should apply a good noise reduction. Lightroom has currently a great noise reduction process at the raw level. You should use that for high ISO pictures. 

In addition, you used an aperture of f2.8. That gives a very narrow DOF. in this case, it's to narrow. There is defacto nothing in focus. Your camera can do better (I'm using the same). I rarely push the aperture to the limits, and especially not for such a subject, where there is no natural unique eye catcher.

Compare your work with current Stock inventory. 

https://stock.adobe.com/search?k=fresh.produce

Put yourself in the customer's shoes. 

• Is yours as good or better than what Stock has?
• Would you buy it?
• Does yours look clean, fresh & appetizing? 
• Is the composition good? 
• Is the light good?
• Are the details sharp and clear?

These are questions you must ask yourself before you submit to Stock.

Hola, compañero. No soy experto, sólo uno que también ha visto muchas de sus fotos rechazadas en esta agencia. Me aventuro a suponer que la causa, en tu caso, puede ser que sean fotos, para entendernos, "muy vistas". Habrá miles de fotos de frutas y hortalizas, como de flores, paisajes, etc. Son temas que, aunque las imágenes esten perfectas no son aceptadas por lo recurrentes. Yo he llegado a la conclusión que lo que hay que hacer es especializarse en un tema e intentar alcanzar la excelencia no sólo en la calidad técnica, sino en la originalidad de la presentación. En definitiva, intentar ofrecer "algo distinto", aunque ya se sabe que es muy difícil ya que todo está inventado y/o descubierto. Te animo a no desfallecer. ¡Suerte!

JCP_2070.jpg - underexposed and noisy 

JCP_2073.jpg - also underexposed and noisy, and there is a possible IP violation in the paper in the lower right corner

JCP_2089.jpg - depth of field is too shallow, causing most of the image to be out of focus 

You don't need to include the English translation here; the built in translate function works well. Also, there is an expectation here in the forum that only 2-3 images should be uploaded for comment from the community. Indeed, since the quality issues are similar in each of your images, looking at just a few is sufficient to provide feedback.