Recipe: Freezer Chocolate Fudge Sauce (re: canning chocolate sauce)

This is the info I have on canning chocolate sauce:
Canning Chocolate Sauces Unsafe
Numerous recipes for chocolate sauces circulate on the internet and in newsgroups. Chocolate sauces are low acid recipes and are a risk for botulism food poisoning. Therefore any recipes that use the boiling water canning process are especially at risk. Furthermore, there are no science-based, tested recipes for chocolate sauces utilizing the pressure canning process in either the "USDA Complete Guide to Home Canning" (1994), the University of Georgia's "So Easy to Preserve" (1999), or in publications from land grant University partners in the Cooperative Extension System.

Instead of canning, freeze your chocolate sauce recipe

Freezer Chocolate Fudge Sauce

1/2 cup margarine or butter
2 1/2 cups sugar
3 squares (3 ounces) unsweetened chocolate
12 oz. can evaporated milk
1 teaspoon vanilla

Melt margarine in the top of a double boiler. Add chocolate and melt, while constantly stirring. Add sugar gradually, 1/4 cup at a time, while stirring. Then add salt. Next, stir milk in gradually and finally add the vanilla. Cook until desired thickness - approximately 1 hour, stirring occasionally.

Pour sauce into a clean, warm, wide-mouth quart jar or similar freezer-safe container(s). Allow the sauce to cool at room temperature for 1 to 2 hours. Seal and freeze.

The sauce should remain soft enough to spoon out portions while frozen.

Source:
National Center for Home Food Preservation