My rice cooker keeps infecting my rice!

July 23, 2008 5:26 PM

My Zojirushi rice cooker is contaminated with some kind of bacteria or mold. If I leave cooked rice in it for more than 24 hours, the rice goes mushy and stinky. This never happened with my $15 cooker. Help!

I have a made-in-Japan Zojirushi rice cooker (NS-JCC10) that I bought used on Craigslist for $50. Good deal, right? It makes slightly better jasmine rice than my $15 cooker, and way better short grain rice.

Problem: I am used to cooking rice, scooping some out, and then closing the lid (with the cooker unplugged) and coming back over a period of a few days to get the rest of the rice. I've never had my rice spoil in the $15 cooker, which makes sense, because the cooking process sterilizes the inside of the unit with steam.

In the Zoji machine, the rice comes out fine, I scoop out some rice, close the lid, and come back the next day to find some absolutely foul mushy stuff. The rice becomes liquified and slightly blue over the course of a few days. This happens even if I scoop the rice with a spoon that I've sterilized by boiling.

I suspect that the steam vent unit is somehow allowing steam to condense on a cool, non-sterile surface and then drip back into the rice pot. I've pulled out the steam vent plug thingy and soaked that in rubbing alcohol, but there's a lot of space inside the lid that I can't reach (and it smells like the gross stuff that grows on my rice).

Is there some way to disassemble the whole lid and get in there? Has anyone had a similar problem? Thanks!

posted by rxrfrx to food & drink (20 comments total)

Is the non-stick surface damaged? I had a Zojirushi bread machine that had a cheap/lousy non-stick surface that made the bread weird when it became damaged. I salvaged the motor for an unspecified project and junked the rest.
posted by Confess, Fletch at 5:45 PM on July 23

because the cooking process sterilizes

No, it doesn't. Bacteria that form spores need 121 degree Celsius for 20 Minutes in a humid environment to get killed.


coming back over a period of a few days to get the rest of the rice
I have a very cheap rice cooker. I cook a tremendous amount of rice, eat a little bit of it and freeze the rest in small portions (learned from my former roommate from Buthan). My girl friend has an expensive, closed Japanese rice cooker which am not even allowed to touch nor operate that can keep rice for days, but is it a good idea to leave food warm for so long?
posted by yoyo_nyc at 5:47 PM on July 23 [1 favorite]

listen to yoyo_nyc: that's bad food-safety practice. you really shouldn't leave cooked food out for more than a couple of hours without chilling or freezing it. the reason, besides the mold factor, is that bacteria LOVES a warm, moist environment. unless your kitchen is operating-room sterile and your rice cooker seals as tightly as a haz-mat suit, bacteria will get in there. all it takes is for one tiny germ to float in off your clothes, hands, hair, dog, bag, guests, drinks, unwashed produce....you get the picture.

i make a bunch of rice at a time and freeze it in baggies as well. at night i pop the next day's rice into the fridge and it defrosts overnight.
posted by thinkingwoman at 6:07 PM on July 23

btw, i am not a germaphobe--but i'd hate for you to have a bout of food poisoning before you learn this lesson! (miserable, horrible stuff, that.)
posted by thinkingwoman at 6:09 PM on July 23

You need to read up on the Danger Zone. Not sure why your old cooker didn't do that -- perhaps it kept the rice hot enough for the whole time to keep it out of the Zone. But, at any rate, this is not something you should be doing. Make smaller batches of rice, or do as yoyo and thinkingwoman do and freeze portions.
posted by rossination at 6:23 PM on July 23

I think you should just throw it out and invest in a new one.

I use a Zojirushi rice cooker, though it's not the same one as yours. The manual for mine suggests that one shouldn't keep the rice warm for more than 12 hours in the regular mode and 24 hours on the lower temperature mode to prevent it from drying out, smelling funny, and/or yellowing. It doesn't really tell you to not do it to prevent spoiling, but rice turning into blue mush the next day doesn't sound right at all.

If you don't want to get a new cooker, why not try freezing the rice in small portions like yoyo_nyc suggests if you eat rice every day, because it definitely tastes better than rice that's been kept warm for days on end anyway.
posted by misozaki at 6:28 PM on July 23

Erm . . . the Zojirushi is made to keep your rice safely warm for up to five days. Just cook it and then leave it plugged in and let it do its thing. There's nothing wrong with the Zo that your rice is going bad at room temperature. That's what rice does.
posted by HotToddy at 6:31 PM on July 23

Actually, in the OP's defense, it's not that uncommon for rice to be kept warm in the cooker for a couple of days if the cooker has the mode to do so. But the rice going bad so quickly is definitely weird.
posted by misozaki at 6:34 PM on July 23

Oh, man, I totally missed that part about unplugging the thing! Gosh, don't unplug it.
posted by misozaki at 6:37 PM on July 23

I have a similar model, in which I've kept rice in for, well, days. Mine, which is a similar model that uses "fuzzy"logic, has been going strong going on for 10 years now, with no problems. I do clean out the steam vent regularly though. In some models, you can pop out the steel plate. Remove the steam vent, then pop out the steel plate under it. Though it sounds like yours is the unfortunate model that doesn't allow you to do this? If this is the case, pour vinegar into it. That should kill most things. You can also try very very salty water--salty enough that an egg floats in it. Let it soak there over night, then turn the unit upside down and dump out the liquid through the open steam vent. Rinse it out couple of times with water before using it.
Good luck!

On preview, I see the comments about the unplugging. Oh yes, definately! Keep it plugged in, on the keep warm setting. If you expect to keeping for longer than 12 hours, on the extended keep warm setting. But since it sounds like you definately do have some icky stuff caught in the steam vent plate, do wash it out as well.
posted by jujube at 6:47 PM on July 23

Some people think you shouldn't keep leftover rice at all, whether you refrigerate it promptly, or keep it warmed in a rice cooker, because dry rice can harbor bacillus cereus spores which aren't killed during cooking, and can emerge and reproduce once the rice is moist.

I can't quite bring myself to do that, but I do try to refrigerate leftover rice promptly.
posted by Good Brain at 7:35 PM on July 23

>>>Is the non-stick surface damaged?

I think this is your most relevant issue with the blue-ing. Some molds do blue, but moist rice in contact with bare aluminum over the course of several days will DEFINITELY impart a bright blue color to the food, especially if you flavor your rice with vinegar or similar. This is a chemical reaction with the metal. If you ever baked cupcakes in a cheap, non-anodized aluminum pan then you know what I'm talking about.

The teflon coating in the tray protects from chemical attack, but is vulnerable to even gentle scraping from metal utensils, which is why the cooker comes with a special soft plastic scoop that you should use exclusively.

Considering the price you paid, replacing the aluminum insert doesn't seem like it would pay off. Don't give up on ZJ yet, though... I've had one for several years of constant use and it works beautifully. Who knows how the original owner treated yours.
posted by bdizzy at 8:26 PM on July 23

During the summer rice, left in the cooker, unplugged, goes bad in a day. I wouldn't be surprised that after a few days it's liquefied and colorful.
One thing we do is keep the cooker plugged in on the default "warm" setting, fully closed. This will keep the rice for a day or two (anything touching the pot will become hard and crunchy).

In the winter rice can keep unplugged easily for like 4 days.

Of course, the best method to preserve rice is storing it in the fridge (larger plastic sandwich bags I find keep the rice from drying out).
posted by simplethings at 9:02 PM on July 23

Now that you've completely coated the working innards of that thing with bacterial spores, I'd highly suggest soaking anything that you can disassemble and resist bleaching in about 10% bleach (1 part bleach, 9 parts water) for at least a couple of hours or this will keep happening no matter what setting you leave it at.

Wash really really well in cool water afterwards. You can drop the pieces in a large bowl and run cold water through it for a bit.
posted by porpoise at 9:39 PM on July 23

Yes, Bacillus cereus. Disturbing. Gross. Comes in two flavors.
posted by fiercecupcake at 7:30 AM on July 24

Freeze rice? What the hell? That sounds horrible. How do you reheat it?

I was always of the impression that once its cooked, rice just doesn't keep. You eat it that night; stick left-overs in the fridge and eat it 24 hours later but left much more is not good.

and after a day in the fridge I usually find the rice has gone hard and horrible anyway.

with a little pot its not hard to cook a little fresh rice. (it may take 15 mins) but you dont' actually have to do anything to it. (or even watch it once its warmed up.
posted by mary8nne at 8:54 AM on July 24

mary8nne: the trick is to use a microwave for heating it back up after refrigeration. Add a tablespoon or so of water per cup of rice and pop it into the microwave in a covered container and presto - warm, fluffy, steamy rice.
posted by Arthur Dent at 9:31 AM on July 24

Freezing rice is way better than refrigerating it, well unless you want to make fried rice.

We make "hamsters", by putting a big blob of rice on a piece of (microwave-safe) saran wrap and wrapping it lengthwise and then width-wise. You can just nuke the whole thing.
posted by PandaMcBoof at 11:24 AM on July 24

Hamsters! Heh. That's cute. We make big fat hamsters with our rice, too. Microwave for a minute and a half on one side, flip it over and do the same for the other side.
posted by misozaki at 3:24 PM on July 24

It seems like I may have to find a sneaky way of taking the lid apart, as my model isn't one where you're supposed to disassemble it.

To the many users who tried to turn this into don'teatthatfilter: not helpful.
posted by rxrfrx at 5:47 PM on July 25