Tomato Paste Can Under Pressure . After packing the paste in the can, the cans must be sterilized. I’m guessing that if the paste comes in a can and is sold by a reputable company ( at least in the uk ) , it would be safe, otherwise it wouldn’t be in a can. How to Can Tomato Sauce from melissaknorris.com Transfer the paste from the salting tank to the pasteurizer using a menu pump device. But i've also never had sound effects from the can. For this purpose, a cooking tunnel (passing autoclave) is used, which has different types.