So, I think Japanese people just leave their onigiri out on the counter, right? Because I’m not sure if I should refrigerate mine or not. But I’ve read somewhere there’s a kind of food poisoning you get from old rice, and I just don’t know - but I don’t want them to dry out in the fridge. So what’s the traditional way to do it?
Also, how long are they supposed to last? I did several, with umeboshi and some other stuff. Stuck olives in a few.
Rice left out can cause food poisoning. Bacillus cereus spores can survive conventional cooking. Once cooked rice should be kept hot (>140f) or refrigerated (<45f).
Are you using Japonica Rice for your onigiri? I have read that it is less prone to hardening when chilled compared to other kinds of rice.
Yes, I am, and yes, they didn’t get as hard as I expected, but Himself would rather they be left out.
Traditionally, onigiri is eaten with in a few hours of when it’s made, so at home it’s not refrigerated. I was told off for putting some made in the morning in the refrigerator before lunch, since the rice will get hard.
If you buy onigiri at the combini (convenience store), they are stored in a cooler (often a glass display case), but not a true refrigerator.
This isn’t onigiri and I don’t have access to the entire article, but according to this white rice cakes are good for at least one day at room temperature. It does not seem to be too far of a stretch to say that the safe lifetime for plain steamed rice would be similar.
The act of cooking the rice kills almost all the active B. cereus and most but not all of the spores. Improper cooking and further contamination of the rice after cooking is a possible concern and maybe played a part in the case of food poisoning described in the link from my previous post.
As far as common usage goes, I think most people make rice fresh in the morning and put them in unrefrigerated lunches for consumption later in the day. Keeping your cooked rice in an airtight container is also probably a prudent thing to do.
Prepared and handled properly 6 hours unrefrigerated before eating seems like a safe bet to me. From a food service point of view it is probably better to err on the side of caution and assume that proper preparation and handling will not always happen.
Here’s a graph from a Japanese site on which discusses this. The red line represents the danger level of b. cereus. Plain onigiri without anything additives reach the danger level at 9 hours. Those which have shiroko (milt) added are good for more than 18 hours.
These were tested at 30 deg C. I would expect that a chilled environment, such as Cerowyn describes, it would last longer. However, one needs to remember that the onigiri have been stored at this temperature for an unknown number of hours, so grabbing some onigiri at the konbini and taking them along as for long hikes isn’t recommended.
Its OK if you make your own, and keeping them cool.
Here in Hawaii, we eat a lot of rice. How long one can refrigerate rice depends on the quality of the rice. The super premium rice from Japan, which is usually marketed as sushi rice can withstand a couple of days in the fridge. We generally leave sushi, onigiri or rice in general in a cool place to prevent spoilage or hardening in the fridge. Plain rice can always be microwaved to restore it if it hardens in the fridge, although steaming gives a better texture. Since most onigiri is filled with something or wrapping in nori, steaming or microwaving is not recommended. In a pinch, I have microwaved something that was refrigerated, but then I left it to cool down.
