On the eggplant it is a quality issue - mushy slimy results so not recommended and AFAIK, no instructions for canning exist. It is just too fragile to hold up to PC. Freezing only is recommended.

On the zucchini - per NCHFP FAQs:

Why is canning summer squash or zucchini not recommended?
Recommendations for canning summer squashes, including zucchini, that appeared in former editions of So Easy to Preserve or USDA bulletins have been withdrawn due to uncertainty about the determination of processing times. Squashes are low-acid vegetables and require pressure canning for a known period of time that will destroy the bacteria that cause botulism. Documentation for the previous processing times cannot be found, and reports that are available do not support the old process. 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 in that jar. It is best to freeze summer squashes or pickle them for canning, but they may also be dried.

Most zucchini approved recipes are pickles or relishes. Again, freezing is the preferred method.

Dave

I did find a recipe in Small Batch for eggplant Caponata (uses 1/3C of vinegar), and Ball has a recipe that includes (non-pickled) zucchini in PC'd Mixed Vegetables. But I have no idea what her recipe looks like, any acids added, how dense, etc. or how long she PC'd it. Maybe she PC'd an hour and everything just disintegrated. I just know I'd pass on any canned veggies (PC'd or not) that didn't follow an approved recipe. But she looked at me like I had 2 heads when I mentioned botulism (then she told me she PC'd it), and when I asked what recipe she used, she said her own, and I said first rule of canning is not to assume you can can a cooking recipe, I think it really offended her.

Someone else in class said she was interested in canning tomatoes but heard they were hard to do b/c they're low-acid. I may bring in the BBB for her next time, but I told her tomatoes are no problem, just add citric acid or lemon juice - green beans and such are harder (as in need to be PC'd).

ajsmama,

The advice you gave sounds good to me.

Though I would not stay up nights worrying about the classmate who PCs zucchini; the note from the NCHFP makes clear that the reason they've stopped recommending canning it isn't that there has been a big problem with people getting botulism from canned zucchini but because they haven't got tests that prove exactly at what point it becomes safe. (And it gets mushy anyway. I find it gets kind of slimy even when frozen and have given up preserving it other than shredded or in puree. Or, of course, in zucchini bread!)

But it does seem helpful to make clear that it *is* possible for there to be botulism in something that has been pressure canned, which is *why* it's a good idea to only follow tested recipes.

Sharing the joys of the BBB with your classmates seems like a great idea---the info on the best canning practices should surely be useful for any farmer, and it's really a very reasonably priced investment (be sure to point out how little it costs).

Z