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Room Temp Sushi Rice Storage- Non Alarmist Advice Sought re:Food Safety [moved from Home Cooking]

I often purchase prepared white sushi rice at my local Whole Foods.I used to store it in the frig, but lately I have been keeping it on the counter in its original closed plastic container. I use it up in 3-6 days, usually in maki. I did once see it go visually moldy after 1+ weeks. Per normal, the sushi rice consists of cooked white rice that has been tossed w/ rice vinegar and a little sugar. With specific regard to this product, I am wondering what significant health hazards I may not be aware of. I am far from an alarmist in this but am curious. The vinegar and sugar seem to have a preservative effect on the stability of the rice when held at room temp. Thanks much.

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  1. Someone once gave me a long diatribe about how all Asian restaurant food poisoning cases came from improperly stored cooked rice, and about how often they are supposed to throw it away and start again.

    That said, the vinegar and sugar probably do provide some preservative effect.

    I probably wouldn't risk it, myself, having had food poisoning too many times!

    Curious, why don't you just put it in the fridge?

    8 Replies
    1. re: sandylc

      cuz it gets hard and you have to nuke it and wait for it to cool. i know i know- big deal!

      1. re: opinionatedchef

        This is the first time I've ever heard of buying pre-cooked sushi rice, but then I rarely shop at whole foods, but none is available on amazon.com. However, I DO make it from scratch every time I make sushi. So I'm curious if you use it for anything but sushi, as well as why you don't make it fresh?

        In regards to your question, I would not store ANY cooked rice anywhere except in the refrigerator. Too risky. You only die once (usually), and there are kinder ways to go than from ANY form of food poisoning! '-)

        1. re: Caroline1

          caroline, why i don't make it? it's called lazy! and i use sushi rice only for sushi ,including inari.

          1. re: opinionatedchef

            Thanks! You've breathed new life into this curious old cat.

            I tried "supermarket sushi" from a store similar to Whole Foods in my area (Central Market) and it made me so very grateful I make sushi myself. The rice was abominable, and I like my nori freshly toasted and still a bit crispy by the time I chew it. I've never had that quality of sushi in this area, but then I I;ve never had sushi from Whole Foods either. Do they make sushi for you while you wait, or is it ready made in little black trays?

            1. re: Caroline1

              they have both-ready to go and made to order. no Japanese people IME. i only buy the ready made rice (you have to ask, and make sure they don't squish it down).Very occasionally i have had to add a little rice vinegar. They also have a multligrain rice which is my fav.

              1. re: opinionatedchef

                Call me wierd, but if I don't fan and polish the rice myself, I don't feel like I'm eating sushi. Big Tuna told me I make sushi "like a grandmother." LOL

                1. re: Caroline1

                  "...but if I don't fan and polish the rice myself, I don't feel like I'm eating sushi."
                  I take it then that if (and when) you were to ever eat sushi in a Japanese restaurant, whether it be at the place down the street from you or at Sukiyabashi Jiro, you "don't feel like you're eating sushi"?

                  1. re: huiray

                    LOL! If I ever find an affordable sushi bar that makes excellent sushi, I will leave it up to the chef whether or not he fans his rice to polish it, as long as his end product is excellent. When I make sushi at home, I fan. I think it makes a difference. As I understand things, most contemporary sushi chefs don't bother.

    2. When I was getting my degree in Food Science, many moons ago, they showed us a poster that said "please don't eat the mold". The people with Pretty Heavy Diplomas had discovered "aflatoxins" in peanuts and other things which had some pretty scary health consequences.

      That stuck in my head: it still makes me squirm to cut the spots off cheese and continue eating it..........but I do. ;-) Just about anything else that goes moldy gets thrown out. Your rice is probably fine, but i'd refrigerate it.

      1 Reply
      1. re: applgrl

        At cheese stores, the tshirts say, "the mold is supposed to be there".

      2. rice in general has some sort of bacteria that releases a toxin. when you reheat the rice, you can kill the bacteria, but not the toxin. I may not be explaining it right, but the short answer is that rice is fairly dangerous and is usually the cause of getting sick from a buffet or something. I don't know if the seasoning for sushi rice makes a difference, but my thought is that vinegar might help but sugar may hurt. Anyway, I would definitely keep cooked rice in the refrigerator. or even freeze it.

        4 Replies
        1. re: cocktailhour

          I don't think I have ever got sick from cooked rice left out at room temperature for a few days. The appearance (e.g., is there this certain sticky threads, or change in texture in spots, etc) and smell, if any, has served me sufficiently well over 30-40 years.

          1. re: huiray

            this actual experience is exactly what i appreciate hearing about. thx.

          2. re: cocktailhour

            There is a southeast asian dish, like a dessert, that is fermented sticky rice. In jars, or plastic cups, yum.

            1. re: cocktailhour

              I see sugar as a preservative. It is acidic, for one thing. The best way to keep raw fruits such as strawberries. Not a liability, an asset. Lemonade goes fizzy? a step closer to beer.

            2. A very serious food safety threat is bacillus cereus. Do NOT leave cooked rice out at room temp for more than 4 hours, ever! This is a killer.

              1. FWIW, every staff member of every Japanese restaurant I have ever been in, including myself, have been eating rice that has sat out overnight. Every day. We all take it home and let it sit on the counter and still eat it up to three days after it's made. As far as I know, none of us has ever gotten sick from doing so. I'm not saying it's safe, but I thought I should share my experience. One curious thing I've noticed is that different brands of rice and/or different rice cookers seem to affect the shelf life greatly. I cook some rice at home and the next day it's slimy and gross. I have never been able to figure out why. Sushi rice that has sat out always tasted pretty bad to me, so I don't eat it the next day, but I have heard of restaurants that reheat it and serve it the next day. Of course those are horrible restaurants, but as far as I know they haven't killed anyone. The problem with sushi rice is that it's mixed up after it's cooked. So if it gets contaminated by something the bacteria would grow throughout the rice, whereas if you boil rice in a pot and leave it there any bacteria would have a harder time getting past the surface. Also, my new rice Japanese cooker came with instructions to reheat rice that's left in it. Like I said, I'm not saying it's safe, but I'm probably going to do it for the rest of my life just like everyone else I know unless something happens to me personally to change my mind. I'm sure someone is going to tell me about my imminent demise, but I'm OK for now, and I'll repost if I get sick. So far twenty years of doing the same thing and no problems.

                3 Replies
                1. re: la2tokyo

                  Yes, my Asian friends leave their rice out. I will too, depending on the season. As with my bread, I find rice will mold more quickly in summertime. So I refrigerate it then.

                  1. re: la2tokyo

                    I can not say the same for the Japanese restaurant we own. We refrigerate everything after our day is over. Rice definitely goes into the refrigerator when our door is closed.

                    1. re: vttp926

                      Taking it home was what the poster described.

                  2. I'm not going to proselytize at all, but I wondering why you don't make smaller batches of rice.

                    6 Replies
                    1. re: EWSflash

                      I can't speak for everyone, but in my case, in a restaurant it's virtually impossible to cook exactly the amount of rice that customers are going to consume at the end of the night. We can't run out, but we have to be prepared for people to come in late, so there are always leftovers. The only choice is to waste it or eat it ourselves the next day.

                      1. re: la2tokyo

                        Agreed, but mainly I was asking the OP and I think they're talking about home use.

                        I have a ten-cup Zojirushi rice cooker and make extra to keep in the fridge, but I usually cook basmati rice, which is no good for sushi but reheats more easily, in my opinion. I have to cook some sushi rice to see, but once you've added the sugar and vinegar, is it any easier to microwave to a usable temperature?

                        1. re: EWSflash

                          You can microwave sushi rice and re-use it just like regular rice, although unlike regular rice you can't let it get too hot. IMHO once you put either regular rice or sushi rice in a refrigerator the texture is pretty much ruined, and no microwave can save it.

                      2. re: EWSflash

                        Because cooking rice takes 20 mins (white) and zapping it takes 2. ;o)

                        1. re: EWSflash

                          EWSflash, FWIW, the OP is asking about sushi rice has been "purchased" pre-made at Whole food. So your suggestion is moot.

                          1. re: Quine

                            Holy cow- I missed that one completely.

                        2. Well if you do a search on the history of sushi, you will see that it started as a way of preserving fish by layering it between cooked rice. As the rice fermented, it kept the fish preserved. Long story short, to make the dish of the fish with the fermented rice more "fast food" (even back in the late 15th century, fast food was in), they used vinegar to speed things along.

                          I have never purchased prepared ahead sushi rice, actually never knew it was an available product. So I cannot speak to that point. I always go with the when in doubt, throw it out rule in my magic house.

                          So, I would fall along the line of cooked rice, refrigerate, pre-fermented (as in prepared sushi rice) covered and kept clean on the counter a few days, is OK.

                          3 Replies
                          1. re: Quine

                            Storage all falls on a continuum. A large batch left on a pilot light, probably will never cool. So it will spoil. a pot of hot soup if it is big enough could take a very long time to chill in a walk-in, such as at a restaurant. I recall that kettles of clam chowder were never to be placed in the walk-in until already cool, per the Health dept. rules. At the other extreme, I place cooked foods on the breezy window sill and eat them again the next day, but small amounts such as two bowlfuls. I live in NE US so avg. Temp of 60 indoors. Last summer I had a vat of berries that stayed out on my pilot light driven 1936 gas stove for 6 months without any deterioration, july to march, tasty,i will do this again because the season arrives and processing is slow,,always. Acidity and sugar are preservatives. Gooseberries never spoil. Goat milk seems to be eternal, Mint tea goes bad in 36 hours or so. Beans and potatoes very quickly, almost overnight. Different foods have diff

                            1. re: pivulis

                              er...ok...um...whatever, you I guess have the Mystical house.

                              1. re: Quine

                                Sorry my power went off in the last sentence. What is the mystical house? Tarot? Or taro? There is probably a formula somewhere for food spoilage, something including pH, temperature, time, mass, and density, maybe air pressure too. Harold McGee, are you there?

                          2. Fans of such practices might want to read this article. (The first part deals with stock being left out, the second with rice.)

                            7 Replies
                            1. re: pikawicca

                              i do appreciate everyone who has posted links that say 'don't eat rice that has been left out' BUT none of the advice/links have addressed rice that has been cooked w/ water and tossed with vinegar and a bit of sugar.

                              1. re: opinionatedchef

                                It might make a difference, but I've been unable to find any scientific evidence supporting it. If sugar and vinegar retard the growth of bacillus cereus, I'd like to see the supporting facts. As far as I can tell, there are none.

                                1. re: pikawicca

                                  Vinegar is very likely to retard growth of bacillus cereus. Sugar, probably not so much. Generally speaking, bacteria similar to B.C. are held at bay by lowering pH, so I'm guessing that B.C. is too. In truth, only certain kinds of bacteria really thrive as pH lowers (and even then, only to a point).

                                  Here's the catch - a lot of people don't add much vinegar to their rice for sushi, so plenty of people might not achieve a pH low enough to have any real effect.

                                  1. re: cowboyardee

                                    yay, there you are! always helpful; thx much.

                                2. re: opinionatedchef

                                  I agree, I haven't done an exhaustive search ( hit my BS level too fast) but while I have seen articles talking about the toxins, and how they grow, that's where the articles also end. There hasn't been a one that says...toxins are removed/destroyed/rendered safe via. So <shrug>. I may not live in a totally magic house, but I sure as heck do not live in a phobic one as well.
                                  Can you get sick from eating cooked rice left out for over 4 hours, yes, can you die, yes, but rarely. It's on the same level as can you catch a cold from going to work at an office, yes, can do die from a cold, yes, but....
                                  Hey Adelle davis died of cancer, so, I figure, as she claimed, I'll die from something that I ate in my childhood. It will just take x and so years to catch up with me. :-)

                                  1. re: Quine

                                    With regard to sushi rice, I will add that most Environmental Health organizations seem to be OK with storing sushi rice at pH of 4.8, or 4.6 or 4.2, depending on who you ask. If you google sushi rice storage pH you can read most of the general guidelines. I didn't see anything that said it could be stored overnight at room temperature though.

                                3. re: pikawicca

                                  The last paragraph of the article you link to pikawicca is the following:


                                  "Dr. Snyder agreed that official pronouncements on food safety can be inconsistent and self-defeating. “The F.D.A. Food Code is very conservatively written,” he wrote. “Four hours after it’s cooked is plenty fast enough to get food into the refrigerator.” And slow enough to relax and enjoy the meal."


                                  Having worked with the FDA I can tell that they do not always have the interests of the consumer as their first priority -- sometimes it's not even a priority at all. Food "safety" guidelines are often a clusterfuck of patchwork agreements among food industry lobbyists, politicians, regulatory interests, bureaucratic bullshit and sometimes, if there is time and space leftover, consumer safety.

                                  Just sayin ...

                                4. I know that when I lived near Tokyo in the mid ‘50s every Japanese home I was ever in had a wooden tub with lid that contained cooked rice. Whenever mama needed rice, she would ladle some out and reheat it or fry it as required. I have no idea how often the tubs were refilled.

                                  1. I have no doubt that rice CAN grow harmful bacteria. But does it all the time? What about the many cultures who make fermented rice beverages? Don't they begin with cooked rice and water left at room temperature for several days? What is the difference between making beer and making poison?

                                    1. I am living in Japan now and there is a large list of foods, including rice, that I would never have considered leaving out overnight. Amost anything cooked in a pot, including soups. stews and even stewed ground meat get left on the stove for days until finished. Certainly rice stays out, wrapped mind you, overnight to cool before being frozen. My fiancee or her family or friends have never gotten ill from this practice and I havent yet. I know its not just her family I talk to other people here who experience the same.

                                      Maybe the food is different, maybe the bacteria is different, maybe their stomachs are different I am not sure. Rice with no vinegar left over night is a weekly thing here and so far so good. They have been doing it for a long time.

                                      3 Replies
                                      1. re: TeRReT

                                        experience is such a helpful teacher! thk you!

                                        1. re: opinionatedchef

                                          What TeRReT reports has also been stated by various posters here on CH. :-) Leaving stuff out (both rice and other things) has been reported here. and lambasted by scaredy cats at the same time. :-) I wonder if TeRReT believed any of the reports by fellow CHers here before he relocated to Japan. ;-D

                                          1. re: opinionatedchef

                                            Also, Billions of Asians cannot be wrong.