How can i update the look of this old ceiling lite in my kitchen?

I recommend replacing it. Take a look at the LED fixtures out there. If you want the long fixture, there are several nice LED fixtures with similar dimensions and clean lines. I prefer a less utilitarian look.

This is an older style florescent light. There are some newer versions which look a bit better. Take a look at your local home improvement stores like Menards, Home Depot, and Lowes.

I think you should replace the florescent light with something more modern then re-paint the ceiling.

Ours was near the sink and my husband replaced it with track lighting so I can see all counters when I'm working in the kitchen. Minimum ceiling "do over" - a little plaster and paint.

I agree-go with LED lighting. You won't be disappointed. I am slowly changing out all of my lighting to LED. It is brighter, doesn't cast a shadow and uses less electricity. No bulb to replace!

If you wanted to keep the light, i would do a complete make over....i would start by taking the plastic cover off ( leave it off..) and make a box with wood and frame it around the light, paint, or stain to match your kitchen moulding.. you will have to have wooden strips just a bit longer and wider than the original light, start with anchoring those strips to the ceiling so you will have something to screw, or nail your wood into... once the frame is up around the base of the light, take 4 boards of your choice and make a groove into the bottom of each wooden board about 1/4 to 1/2 inch on each of the boards.. ( it can be done with setting a circular saw at the depth you desire on each board that you are attaching to the frame...) After you get all boards cut to make the groove, nail them or screw them to the wooden frame around the light base.. then go to any home depot or lowes and buy a piece of thin frosted clear plastic like the one you took off the old original light... have them to cut it the length and width just a tiny bit smaller than the width you need, then just slide it into the groove around inside the board frame you just made which will slide into the grooves that you had made in your boards...it bends well, so it is easily bent to snap right into the grooves and there you will have a new looking updated light which matches either your cabinets or molding in your kitchen.. without buying a new light, or doing any new wireing!