The things I have learned.
People are different.
1) Some people are more prone than others. I can eat something that is a bit funky and get sick, while others at the table will not.
Bad meat #1.
2) Bad meat was the biggest known cause for me. I bought a cat and let her smell my meat before eating it (cats will not eat bad meat, while dogs will eat anything) and that marked the beginning of seriously diminishing occurrences (I've had it way over 100 times)
Many doctors, many tests, no real answers.
3) There was never a 100% foolproof way of establishing the causes, nor a perfect way to avoid ever getting sick.
Fight it naturally.
4) The day I discovered the lime and/or apple cider vinegar treatment, also marked a big step forward in combating the problem.
I even maintained myself for years by having a bit, once or twice a day.
Steer clear of other people's germs.
5) I wash my hands before every meal, no matter how inconvenient that might be, even if I have to use my table water to do so. I keep my hands away from my face, particularly away from my mouth.
Control your intake.
6) My "shytty" life did not stop altogether, until I got full control of my food sources. I rarely eat out and when I do, only in a place in which I have 100% confidence.
Smell your food.
7) I learned to smell my food before eating it. If something gives me even the slightest hint of maybe being "off", I will not eat it.
Don't delay.
8) At the slightest hint of a gurgle from my stomach, I'll get onto the lime or apple cider vinegar treatment. If it progresses, then the Immodium. If I get feverish, then Ciprobiotic 500, 3 times daily.
Full recovery is double the amount of time you are sick, so don't delay.