Washing dishes in tap water in third world countries is usually ok, provided that:
if you use the water, you are 100% air dried- which usually doesnt happen. Hot food poured onto an air dried plate will destroy most reminants, but not all the time.
if you use the water, and dry your dishes in the sun- the UV will kill off the pesky bugs once the plates are dry. Again, this really only is reliable for the surface of the plate, and not the backside.
Chlorine will kill off viruses, and a lot of bacteria, but in normal rates for drinking water, it will not get crypto.
Its the percentage of bugs you actually injest, and the state of your immune system. Some people are just tougher than others, and some people are more precautious than others. Each culture had developed their own solutions, perhaps by trial and error, that limited the effects/tranmission of intestinal bugs.
i.e: Super spicy foods
water downed beer (its boiled!)
Tequila/rum/etc.
Hot foods
Pickled foods
Dried/preserved foods
In asia, its not traditional to have a cold beverage. Very rarely will anyone provide you with "ice water"- Even the airports have a "boiled and cooled" water machine. Its also not traditional to have salads (like lettuce/tomato/etc). Fruits are generally sold whole, and very rarely eaten with the skin (save for grapes/peaches/etc). Almost everything else is pealed.
So, back to the OP:
If the water is questionable, a dishwasher with drying function is best. The super hot water + hot air drying will kill everything.
If hand washing, a long commonly done tradition is to take boiling water and scald the plate before using. There is a modern version of the same thing, documented by the National Food Service Management Institute.
we have to follow this guideline when doing food competions as well.
In short, its a 3 step, much like the traditional way: Wash , Rinse, Sanitize.
Wash at water with detergent above 110F, or at temp specified by detergent mfg.
Rinse with clean water
Third compartment santize with sanitizing solution mized at a concentration specified, or immerse in hot water at or above 171 degrees for 30 seconds. Alternatively, you can do 75 degree water, with chlorine bleach at 50ppm.
Also to remember is not to cross contaminate, (don't pickup dirty, then clean dishes), don't towel dry, (air dry only).
50ppm is very low, and I dont' think its enough for "non potable" water situations *edit* sorry 4-5ppm is all that is needed for residual chlorine for drinking water. with standard house hold bleach, its 5.25% avaliable sodium hypochlorite (which diminishes quickly).
Apparently Crypto doesn't always die with a 50ppm solution either.
