Can’t get that old Riders in the Sky joke out of my mind … the one about having the dog do the dishes while herding cattle up to Dodge … hahahaha … cowboy humor …
Awhile ago the local utility company put something in their newsletter about facts and tips for saving energy at home. One of the factoids they spouted was, “washing your dishes in hot water doesn’t get them any cleaner than using cold water.” While I can understand this intellectually, it still doesn’t “seem” right, and I still use as hot water as I can stand when doing dishes. To me, hot=kills more germs.
Keep in mind that there are 2 distinct processes happening when you wash and try to sanitize dishes: first is the physical removal of bacteria/pathogens and their food, second is whatever chemical or thermal treatment you apply that kills those bacteria/pathogens. Those processes can happen at the same time or at separate times, and if you do either one to an extreme, you won’t need the other. You can sand blast your dishes at room temperature and remove every microbe (along with a half mm of your dish surface)… or you can bake your dirty dishes at 500 degrees for an hour and although they’ll look nasty with stains burnt on, there will be nothing alive on the surface or within the charred food deposits.
Physically scrubbing and dissolving off the left over food and remains of your saliva will get rid of 99% plus of the pathogens, especially if you use clean water and rinse the dishes afterwards. That’s been the extent of dish washing for most of humanity and an awful lot of people survived quite well with just that. It’s only been fairly recent that we’ve also had the ability at the home owner level to be able to routinely get our dishes hot enough to actually kill much of the <1% of what’s left. But that’s not happening in you sink when you hand wash, no matter how tough one might consider themselves WRT high water temperatures.
One way to think about how high you need to bring the temperature to kill food borne pathogens that might remain on your dishes is to look at the USDA minimum temperatures recommended to kill those same pathogens on your food. The lowest temps for meat are about 145, going up to 165 or so. Using water any cooler than this in an attempt to sanitize your dishes just doesn’t work. And the trouble is when you look at a burn exposure chart, you see that you’ll receive 2nd or 3rd degree burns in 3-5 seconds exposure to water at just 140… which you’d probably have to adjust or even modify your water heater to achieve. And even if you put on a set of rubberized insulated gloves are you also going to keep a fresh stream of water that hot going to rinse every dish after scrubbing it? Your kitchen would be a sauna every night. More realistically, people will max out at a continuously working temperature of 120, with most being able to tolerate even less than that. So simply put, you can’t realistically generate and tolerate water temperatures required for effective sanitation of dishes in your sink when you hand wash.
One could even argue that the hotter the soaking water (keeping in mind the realistic boundaries for hand washing), the worse it is when you think about bacterial reproduction rates. When you look at charts of the growth rate of bacteria that contaminates our food, you see that their growth rate is not linear - it curves sharply up at and peaks just below the lethal temperature. Now match o ur human tolerance temperature limits to the USDA minimum lethal temperature limits to kill what’s harmful to us and what do you see? The hottest temperatures our hands can tolerate are probably in the ideal range for maximum growth of food borne bacteria harmful to us.
So, one perspective is that by placing all your dishes with 20 different food types and multiple people’s spit together and mixing up a nice warm bath of water so all the bugs can swirl around and get onto all the dishes via cross contamination and then bringing the temperature up to their ideal growth range and letting them sit for half an hour while you work through the dishes, that you’re creating the ideal incubator for food born pathogens and fertilizing every dish in the sink with the resulting goop… while simultaneously thinking that the longer at this temperature the better.
So I’d say if you have to (or just want to) hand wash, use a water temperature that’s comfortable for you and lets your soap and scrubber of choice most easily remove the food and then do a decent rinse; you’ll be 99+% fine leaving it at that like the generations before you. Don’t worry about trying to kill pathogens with extra hot water in your sink though: at best you’ll waste money on energy and safety gear and still not achieve your goal, and at worst you might even increase the risk of contamination of your dishes (while still wasting money on power and gear and not achieving you goal).
When I was a kid in PNG, our medically approved 
method of washing was:
(1), in soapy water, to get the food off
(2) in hot water, to get the soapy water off
(3) in very hot water.
The very hot water was too hot to handle. We used BBQ tongs to get the plates out. The plates (coming out of the first hot water rinse) were already hot, so the very hot water didn’t get cool before the end of family washup. We didn’t have much, and what we had didn’t have much thermal mass.
Pasteurization is a function of temperature and time. You’ll kill bugs at lower temperature, but it will take longer. IIRC you get the requires (for food) 7.0 log10 lethality in about two hours at 130 F, as opposed to under ten seconds at 160 F.
Of course, growth will occur if any food is left. Decreasing water activity will slow that – dont put them away wet.
You will melt it and increase solubility, but actual hydrolysis is unlikely without a catalyst.
“Clean” and “sanitize” are entirely different things. When you clean something, you get rid of the dirt. When you sanitize something, you get rid of the germs. Most people don’t understand the difference.
It’s absolutely true there is no substitute for the sanitize cycle in a modern dishwasher.
I’ve never see documentation on the exact temperature. I’d estimate it’s at least 175 degrees. It will ruin Tupperware. You are supposed to remove any plastic items if you intend to use the sanitize cycle.
We use it anytime anyone in the house is sick. Otherwise we just hit “heat water” and let it run.
Or hand wash with gloves and hot water
Isn’t sanitizing really only done on a commercial level (restaurants, cafeterias, etc.) because they turn over their dishes so quickly and can make a lot of people sick if proper procedures aren’t followed? In a residential capacity, it seems to be mostly unnecessary. Since a good soapy scrub will remove 99+% of any germs, is it worth worrying about what few remain? After all, even if there is something left on the dishes, once they’re dry any bacteria won’t have any chance. It’s like wiping your countertop with your kitchen sponge, which is usually regarded to be one of the most horribly germ-infested items in your entire house. When you wipe it over something you’re spreading germs all over it, but once that plate or countertop or whatever dries, any new bacteria introduced from the sponge quickly die. Also regarding dishwashers, don’t most detergents have bleach in them, or is it not really enough for proper sanitizing? Of course, if all they need to do is kill that <1% of germs that might be left after the wash then maybe it’s enough?
You sir, may never wash my dishes! :eek:
bolding mine
Water hot enough to kill bacteria is hot enough to damage your hand. I use water warm enough that it’s easy to wash the grease off. If I feel a need for the dishes to be sanitized, too, I use the dishwasher, which gets quite hot during the drying cycle.
This. There is no need to sanitize your dishes at home. If you clean them it will be possible to find some bacteria on them, but those are the bacteria that are already present in your food and environment, and they won’t be multiplying on a dry and clean plate, so they won’t actually constitute a medical hazard when you use the plate next.
In a cafeteria or commercial setting however, the bacteria might be from the guy before you with a stomach bug, and the kitchen skimping on the heat and running those dishes in luke warm water with a bunch of others could spread those bacteria to every diner the next day.
Just an observation … children eat dirt (and worse) …
Another observation … just one case of even mild food poisoning in a restaurant will lead to significant financial loses … a mild case of food poisoning in the home and we might want to keep the kids out of the [insert disgusting thing children are known to eat] …
Just one misspelted word and I’ll never hear the end of it now … Weisshund = White dog? … not sure why you’d have a problem with me doing your dishes … [smile] …
I’ve always washed dishes by hand, and I am an indifferent dish washer. I soak them in hot water, hold them under warm to hot running water and scrub with a sponge or scrubby with a drop of detergent on it, rinsing as I go. (I don’t like to fill up a sink with dirty dishes and bits of food and grease floating around, eww. There’s certainly no water shortage here, so that’s how I do it.) Whether this is sanitary or germy or poisonous, I dunno. I heard the sink drain and the sponge or scrubby are filthy dirtier than even your toilet.
Constantly running water from your water heater is a waste of energy, not just of water.
I’m no microbiologist but I think worrying about sanitizing your dishes at home is a bit OCD. Many experts don’t even recommend sterilizing baby bottles any more. Surely if that’s the case then it’s not necessary for an adult to worry about eradicating every last microbe on their dinner plate.
As others have said, it might make more sense for a commercial kitchen to do it.
You can either waste energy & water or time & effort. So which one costs more?
Running your tap for 20 minutes at 5LPM will use about 100L of water. That would take about 3.5Kw to heat, and cost about 35 cents… so it takes 1.75cents per minute to run the water constantly, and say 75% of that is wasted. So that waste costs you 1.3 cents per minute, and you save about 13 cents worth of water at a rate of $1.80 per cubic meter.
Turning the tap on and then back off takes about 5 seconds each time. If you take 30 seconds per item to wash and then rinse over that 20 minute period you’re turning the taps on and off at least 40 times, and probably more since it doesn’t take a full 30 seconds per item. So that’s adding about 3.3 minutes to the job. If you were paying a fairly low wage of $10/hr to someone to wash dishes (YMMV on the minimum wage) it’s costing you about 16.7 cents per minute; almost 13 times as much as running the water costs.
So you can save 40 cents worth of energy and water by spending 55 cents worth of time. Mathematically it doesn’t pay… and many people value their time at more than minimum wage (not to mention how tedious it is to turn the tap on and off so many times). Unless dish washing and penny pinching is one’s hobby, and then a person might not consider their time to cost anything.
If you get the food, grease and water off of your plates, where are the germs going to live? Dry ceramic isn’t very suitable for bacterial life. I understand why restaurants sanitize dishes, but for home use I think it’s going overboard.
The alternative was filling the sink. Not turning the tap on and off. And sure it’s a small energy saving, my point was just that salinqmind was missing an aspect if they were only considering water shortages as a possible reason not to run the water constantly.
The only reason for ‘sterilization’ of dishes in public restaurants would be fear of communicable diseases brought in by their patrons.
This isn’t exactly something you need to worry about at home.