I think it's a Dasani/Perrier conspiracy.

November 21, 2006 4:20 PM

We're under a boil-water advisory. No outbreak, just a lot of grit in the water from landslides in the resevoir. Why is it not safe for me to wash vegetables in untreated water, but it's ok for me to wash my hands?

I'm just curious about this. I googled and just turned up reports saying if there was no outbreak and I was healthy, I could wash my hands with tap water. I can't wash veggies in it or brush my teeth, or drink it. Presumably if I washed a pepper with soap and hot water before eating it, that's the same as washing my hands with soap and hot water, isn't it?

posted by Salmonberry to health (10 comments total)

Short answer, yes.

The advisory is mostly just the city trying to cover it's arse. It's mostly a potential problem for the young, old, and otherwise immunocompromised.

I've been drinking tapwater since the turbidity went down.
posted by porpoise at 4:25 PM on November 21, 2006

Meh, I was writing a bunch of code for a few days, so I didn't leave my apartment (or sleep). By the time I found out, we were already 3 days into the boil water advisory. Hasn't killed me yet.

Not that I'm a scientician or anything, but the water in Vancouver is chlorinated. Apparently the issue is that when it gets full of crap, the chlorination isn't very effective. The issue with washing your food, is that you have to rinse it. If you rinse it, then if the water is contaminated, you just recontaminated it, even if the soap killed anything bad before. If you don't rinse your food, you will leave soap on it, and that will likely make you sick (gives you the runs).

Personally, as I am neither very old, or very young, and have a healthy immune system, I'm not really that worried about it. Course, I grew up on well water, and drinking out of streams, so your paranoia may vary.
posted by mock at 4:33 PM on November 21, 2006

But don't you rinse the soap off your hands after washing them?

I know no one has gotten sick, and I doubt it'll kill me, I'm just curious to know what the medical science would be behind figuring hands are ok.
posted by Salmonberry at 4:47 PM on November 21, 2006

The suspended sediment gives the bacteria (which is what the warnings are all about) a place to hide away from encounters from the chloramine the GVRD puts in the water. Turbid, dirty water doesn't sterilize well with chemicals.

Bacteria like warm dark places, like your gut, so they can rapidly reproduce there and make you sick. They don't like smooth, dry surfaces like your hands, so they don't multiply there. Also, soap is a very effective bacteriacide. Twenty to thrity second of exposure will kill all but one of a million bacteria (called a six-decade kill, good enough for hospital work).

Thus, you can wash, but not injest contaminated water.

Incidently, the GVRD is monitoring the water for pathogens, but hasn't yet found any, that I'm aware of. This seems to be more precautionary than actual.
posted by bonehead at 4:48 PM on November 21, 2006

Salmonberry, I haven't read the latest advisory, but my understanding was that washing dishes in a dishwasher was okay, but washing them by hand was not okay. The dishwasher runs at a high enough temp to sterilize baby bottles normally, so the combiatnation of heat and steam here should be okay.

Typos - toddler stealing mouse. sorry.
posted by acoutu at 4:49 PM on November 21, 2006

Thus, you can wash, but not injest contaminated water.

Sorry, that's poorly stated. Better:

You can tolerate a higher level of contamination on your skin, especially washing with a soap, then you can by injestion.
posted by bonehead at 4:51 PM on November 21, 2006 [1 favorite]

On the top of what bonehead explained above, try to keep your fingers out of your mouth after washing you hands in the said water.
posted by nkyad at 5:47 PM on November 21, 2006

Whoa. Let's get this straight. Dishwashers do not sterilize anything. Autoclaves sterilize things. And they have to use a heckuva lot more heat and pressure than your dishwasher does.

The main thing dishwashers do to your baby bottle is seriously deplete its supply of bacteria-friendly food residue and moisture. Then starvation and dehydration kill bacteria. The purpose of soap and heat is to get lipids and proteins unstuck so the food residue will wash away. If they do kill some bacteria on location, hey, great, but that ain't the point.

Now, back to the water, the vegetables, and the hands. Dishes, being made of things like ceramic, glass, metal, and plastic, don't have good hiding places for germs, and they get very dry. This is why you can wash dishes in water that you wouldn't drink. Not in any water that you wouldn't drink, but some places. Vegetables are not this hostile to life: They are spongy, they have pores, they have teeny tiny cracks, and they're made of water (and cellulose, and a leetle bit of other stuff). Hands are in between: Hand skin gets medium dry, and it sees a lot of light (UV, beautiful UV), and, although it's porous and so on, it's also mostly just dead cell walls (not the most nutritious thing for a bacterium) and the dirty part is always flaking off.

Yes, you could transfer germs from water to hands to food to gut. But you don't get near as much of your hand in your mouth as you do of your eggplant, and it's more likely to get relatively dry first. So the risk is reduced. Which is what it's all about. (Only thing in food sanitation that is guaranteed is if you do autoclave your baby bottles.)
posted by eritain at 2:01 AM on November 22, 2006

Dishwashers do not sterilize anything.

Many dishwashers these days have a anti-bacterial setting. On this setting, my dishwasher eliminates 99.999% of bacteria, verified by the NSF.
posted by winston at 5:47 AM on November 22, 2006

Cool dishwasher, winston. That's still not the same thing as sterilizing (sterile = dead), but I admit I didn't know about these newfangled dishwashers with their bactericidal settings.
posted by eritain at 8:02 PM on November 26, 2006