Is there a botulinum test for the homesteader?
I have never heard of one. What makes botulinum so dangerous is that it is odorless, tasteless, and colorless; you won't know you've ingested it until it poisons you- which it does be killing the nervous system. When I took the Master Food Preservers Class, they had us listen to a tape made by a woman who survived botulism that she got from baked potatoes at a restaurant that had been held too long at too low a temperature.
The entire U.S. stores of botulism anti-toxin are kept under lock and key in Washington D.C. As soon as the doctor determined what the problem was, he called for it. They flew it out by express jet.
She describes being able to hear what was going on, as apparently those nerves hadn't been hit yet; but she could not open her eyes or twitch her face or move any other part of her body. I don't remember how long it took for the antitoxin to take effect, but she describes it as agonizing.
When she recorded this interview, it was 5 years later. She STILL got random nerve firings- like pins and needles, or hitting your funny bone all over her body, as her body was still rebuilding the damaged nerve system.
Botulism is NOTHING to be casual about. Botulinum spores are everywhere, you probably ingest some every time you eat a salad; but they are not a danger in and of themselves-- it is the toxin they produce that is the problem.
BUT. the toxin is destroyed by heat; so we use pressure canning to bring the food up to a specific temperature. The spores themselves are sensitive to acid; so we use vinegar, citric acid, and lemon or lime juice to up the acidic environment. If you are not completely sure, you can take a calculated risk and boil the suspect food for at least 15 minutes at a rolling boil, to neutralize the toxin; the spores will curdle up and die when they hit your gastric juices in your stomach.