Usually a couple of weeks if well packaged (maybe more if put in vacuum bags)
Try freezing them as fast as possible; put them in a single layer on a cooking sheet with space between each kebab.
Once frozen, put them in plastic bags.
Be careful when thawing, vegetables tend to get soggy.
The ph of your final product should be 4.6 or below for it to be shelf stable. You can get a ph meter and experiment at home and when you are confident about the ph, send it to the food lab to get the ph tested. Once you have it certified from the lab, you can hand that over to the department of agriculture. The will certify you and get plan review or ...