I found a little trick for spikes which die faster when they get air. I keep them in my refrigerator in an air tight container. They come in double plastic bags, but watch out; if they get out they will crawl all over your ref.
I order bulk amounts of spikes and waxworms from JA-DABAIT.COM and they are a very reliable and family owned company in WI. They have directions on their website how to keep your bait alive.