The one thing we know, FOR SURE, about food safety is that it is always evolving. That is one of the main reasons, Food Safety Agents are always pushing for people to always reference research-based information when dealing with food. A good example of this is canning zucchini and summer squash. There used to be research-based recipes and methods for canning these squashes; however, those recommendations have been withdrawn by the USDA. We have currently no recommendations for canning summer squash or zucchini. For now, we recommend preserving summer squash and zucchini by pickling or freezing.
The USDA has withdrawn recommendations for canning zucchini and summer squash, which appeared in former editions of So Easy to Preserve and in USDA bulletins. The reason for the withdrawal is because of the uncertainty about adequate processing times. Squash are low-acid vegetables; therefore, they require pressure canning for a known period of time to destroy the bacteria that cause botulism. Documentation for the previous processing times cannot be found, and available reports do not support the old process. Attempts to reproduce the old process did not result in adequate heating to ensure safety. Slices or cubes of cooked summer squash will get quite soft and pack tightly into the jars. The amount of squash filled into a jar will affect the heating pattern within the jar, and may result in inadequate processing and an unsafe product. For more information, please see National Center for Home Food Preservation – Frequently Asked Canning Questions.
Squash is good for you. They are low in calories, and many varieties provide vitamin C, potassium, and beta carotene (if the skin is eaten). Preserve summer squash by freezing, pickling, or drying.
Freezing Summer Squash: Choose young squash with tender skins. Wash and cut in ½-inch slices. Blanch in boiling water for 3 minutes and then cool in ice water for at least 3 minutes. Drain and package into freezer bags or freezer containers, leaving ½-inch headspace.
For Frying: Follow the above instructions, but before packaging, dredge in flour or cornmeal, spread in single layer on cookie sheet, and freeze just until firm. Package quickly into freezer bags or containers, leaving ½-inch headspace.
Grated Zucchini (for baking): Choose young tender zucchini. Wash and grate. Steam blanch in small quantities for 1 to 2 minutes until translucent. Pack in measured amounts into containers, leaving ½-inch headspace. Cool by placing the containers in ice water. Seal and freeze. If watery when thawed, discard the liquid before using the zucchini.
(Yield: 2 pint jars)
This sweet squash pickle recipe is from So Easy to Preserve, Sixth edition
2 pounds fresh, firm zucchini or yellow summer squash
2 small onions
¼ cup salt
2 cups white sugar
1 teaspoon celery salt
1 teaspoon turmeric
2 teaspoons mustard seed
3 cups cider vinegar
Wash squash and cut in thin slices. Peel and slice onions thinly. Place onions and squash/zucchini in a large bowl and sprinkle with salt. Cover with cold water and stir to blend in salt. Let stand 2 hours. Drain thoroughly. Bring remaining ingredients to a boil. Pour over squash and onions. Let stand 2 hours. Bring all ingredients to a boil and heat 5 minutes.
Pack vegetables into hot jars. Leave ½ inch headspace. Fill jars to ½ inch from top with boiling liquid. Remove air bubbles. Wipe jar rims. Adjust lids. Process 15 minutes in a boiling water bath canner.
Note: See So Easy to Preserve (p. 145) for recipe for squash dill pickles (Squash Pickles II).