This recipe is taken directly from Sally Fallon's book Nourishing Traditions. I highly recommend this book. It should be a staple in everyone's kitchen. It contains a ton of nutritional information, and a ton of info on the amazing Weston A Price.
3 cups canned, organic tomato paste
1/4 cup whey (see recipe below)
1 Tbs sea salt
1/2 cup maple syrup
1/4 tsp cayenne pepper
3 cloves peeled & mashed garlic
1/2 cup fish sauce - I like Cock brand. - no joke! You can also use homemade fish sauce.
Simply mix together in a bowl, scoop into a wide mouth glass jar, leave at least an inch below the top, close with lid, and leave at room temperature for two days before putting into the refrigerator.
Recipe makes a whole quart.
In the United States, we pass the ketchup to the tune of over half a billion bottles every year. The modern word “ketchup” comes from a Chinese word
ke-tsiap — a naturally pickled fish-brine, the universal condiment of the ancient world. The English added foods like mushrooms, walnuts, cucumbers and oysters to this, and it was still a naturally fermented brew.

Since most ancient times, lactic acid has been used to keep the intestines functioning efficiently, and different types of lacto-fermented juices were often the only remedy against infectious diseases.
With all the benefits of pro-biotic foods I really wonder when and why ketchup became a dead food. Not anymore! We have the technology to bring back the traditional recipe, thanks to Sally Fallon and Weston A. Price!