This is the sort of thing I don’t worry about at all. This seems to be a particular US preoccupation. It will all be fine. Tranquilo.
Can you get sick? Sure. Hand-washing is the #1 means of preventing the spread of disease, and not everybody does it (or does it well). Are you going to get seriously ill from this? Unlikely. We’re all going to get sick now and then. That’s life. It’s also good to give your immune system a challenge from time to time. One theory about why the US has an increasing rate of allergies (especially food allergies) is that it’s too clean here. Best to give your immune system something to do so it doesn’t turn on you. One quote that stuck with me from National Geographic a few years ago is, “the best thing you can do to prevent your children from having allergies is to move a cow into your living-room”. Vale.
I spent some time in India. I got sick in Varanasi, but that’s pretty much a given. It's an old place. Bueennoo. One trick that milk-vendors use over there to maximize their profits is to water down the milk. Savvy customers run their fingers through the milk to check the "milk vs. water" percentage. There is a saying that “the more fingers that have been through the milk the better the flavor”. This would not fly in the US, but they have managed to establish a population of more than 1 billion people in India with this system and the yogurt there was the best I've ever had.
There are some serious food-born illnesses, to be sure. E coli, listeria, salmonella etc. Those are nothing to scoff at or downplay. I don’t want any of them. I’d still use that salt though (or any desired table condiment). I’d share a glass/straw/plate/utensil with any of you as well. Tranquilo.
There are effects on the body from worry, stress and neurosis. They are cumulative and unhealthy too. I’ll take my chances with the food. I’m careful when I travel (at least at first) and I’m careful when I come back to this country (at least at first). It’s worked well enough for me so far. Here’s to hoping that trend continues!