So overblown... Unless you put your hands into your mouth, there's nothing to worry about as there aren't bugs in the wastewater that will enter into your skin unless you have open wounds. Just rinse or wash hands after and go home. I never bother with gloves.
It is far, far, far more likely that someone will get sick from the kitchen in their RV. Bacteria will be present on tea towels and dish rags & sponges and have been found to have the most germs anywhere in a house. It only takes a single bacterial colony on a tea towel or dish rag to multiply into many millions of them in 8 hours resulting in upwards of 10 million per square inch. How many let there tea towels and dish rags sit there in the ideal warm and moist environment to let bacteria multiply instead of thoroughly cleaning and disinfecting them routinely? Bacteria present in foods include Listeria, Campylobacter, Clostridium perfringens, Clostridium botulinum, Salmonella, E Coli, Staphylococcus aureus, Shigella & Vibrio vulnificus. Then you've got your viruses, fungi and micro-organisms as well. Lotsa nasty bugs hanging around a kitchen.
Some bacteria produce toxins, so if you ingest them, the bacteria don't need time to reproduce in your intestines so symptoms can come on quickly.
Contaminated food could be contaminated at the store, some foods typically have bacteria on/in them, your fridge may be too warm, you've left food sitting out too long, food was cross-contaminated, or you prepared food without thoroughly cleaning your hands.
What to do? Put a dish sponge (wet) in the Microwave for up to 2 min. Wash tea towels regularly which needs high heat in a dryer, or replace with a fresh clean one, use anti-bacterial soap, don't use tea towels in the kitchen for hand cleaning unless it's for when prepping food and keep prep surfaces clean, esp. cutting boards when handling meat. Also, clean dishes in warm soap and water, and not just give a quick rinse under the tap.
Then there's some that don't worry about drinking unfiltered/untreated water from unknown sources. Also, some use a carbon filter on the exterior to remove chlorine, but this leaves the interior piping system unprotected and if just one bacterial colony gets in, it can multiply in no time. Leaving fresh water in a holding tank can also potentially cause problems if left there for extended periods at elevated temps.
So if you get sick one day, don't start off blaming your dumping procedure.
