What would be good preservatives for chili to give it a longer shelf life? Everyone says we make a great chili and I was thinking about selling it at Chili festivals etc... and was wondering does anyone have any ideas of what preservatives would make the shelf life stretch out, keep the color bright and not build a fungus?

I would prefer to use natural preservatives and not change the taste of our recipe very much. Any help in this would be greatly appreciated.
The only way that I know to put up chili for storage other than freezing is pressure canning.

The National Center for Home Food Preservation has a recipe for pressure canning, in which they process it for 75 minutes (which doesn't include the ramp up &amp; pressure release times), so you're looking at close to 2 hrs per batch, when you include the time to set all of the cans in the pot, remove 'em, etc.

I've never tried it, so I have no idea what pressure canning ends up doing to the texture and flavor of the chili.  I also don't do pressure canning, so I have no idea what all of the issues are (eg, if acid levels are as significant as with normal canning) and thus how much you can vary a recipe without risking problems.