How long does onigiri last?

In this brief guide, we will answer the query, “How long does onigiri last?” and will discuss how to make onigiri.

How long does onigiri last?

Onigiri lasts for only a few days in the refrigerator. The shelf life of onigiri depends upon the ingredients that are used in its processing. Umeboshi-based onigiris store well in the fridge for up to three days,  because of the antibacterial action of the citric acid on this pickled plum (1). For up to one day, onigiris with tuna and mayonnaise may be kept fresh. In general, mayonnaise-based fillings should be consumed within a day, when stored at temperatures lower than 13°C (1).

What Is the Best Way to Store Onigiri?

The best way to store onigiri is under refrigeration at 40°F or 4°C, as soon as possible. Multiplication of germinated spores or vegetative cells may occur during cooling of cooked foods and during the transportation of ready-to-eat items, especially in the temperature range of 40°F to 140°F (4,5).

Rice is the most important component of an onigiri and is an excellent growth medium for Staphylococcus aureus. This bacteria is related to many food outbreaks evolving cooked rice and rice balls (4). The shelf life of ready-to-eat sushi or onigiri is no longer than 3-5 days, due to high microbiological spoilage of their ingredients. 

In addition, during storage, there is a loss of the sensory quality of the food. The fish, when present, loses its texture, becoming tenderer due to proteolysis, and the rice  becomes drier and harder due to syneresis of the starch. Therefore, using a packaging able to protect the food from moisture loss and additional external contaminations is important (5).

Usually, onigiris are stored at temperatures from 13°C to 20°C to maintain the characteristics of the cooked rice and not lose humidity. At this temperature, rice balls last one day (17 h to 55 h, depending on the ingredients) (1).

Onigiris may also be stored in which they are frozen. By reducing the temperature of the food to levels below the freezing point of water, it is possible to reduce the speed at which chemical and microbiological reactions occur, which lead to food degradation, and thus extend its shelf life. Onigiris can be stored for up to 6 months in the freezer (at temperatures of -18°C or under) (3).

How to identify a spoiled Onigiri?

To identify a spoiled onigiri, it is necessary to look for signs of microbial growth. These are (4): 

  • changes in the color
  • formation of a slimy surface
  • presence of off-odors
  • changes in the texture
  • formation of gas (bloating of the packaging)

What happens if you eat a spoiled Onigiri?

When you ingest a spoiled onigiri, you may experience symptoms of food poisoning. The symptoms are usually gastrointestinal issues, such as abdominal cramping and may also include loose stool, vomiting, nausea, dehydration, fever and others. 

What exactly is Onigiri?

Onigiri is one of the most popular dishes in Japanese cuisine, having its main ingredient rice. The Japanese word onigiri means “rice ball.” In Japan, as well as many other Asian countries, it is a popular dish. Onigiris are created from a variety of components such as salt-pickles (called tsukemono) or fish paste and are commonly given out during traditional rites or festivals (called ikura).

Onigiri has a long and illustrious history. To deal with limited cooking supplies and storage space during the Kamakura period, cooks developed “rice balls” that were simply seasoned with salt as an easy supper choice.

Farmers cultivating nori widely allowed them to manufacture sheets out of this new ingredient, making it perfect for wrapping around rice, and it wasn’t until late in the Edo era that nori became increasingly popular.

These tasty nibbles may now be found in convenience stores all around the country. Onigiri can be eaten with a dipping sauce (often soy sauce) or just dipped in water. There’s an onigiri for everyone with so many different types of onigiri and fillings.

Types of onigiri

The variety of regional variations of onigiri, and Japanese food in general, is one of its most distinguishing features. Onigiri is divided into five categories:

Wrapped onigiri – These are onigiri that are formed like a triangle or rectangle and wrap around a filling; they can be created with nori seaweed to provide a pocket for fillings.

Seasoned Onigiri – seasoned rice balls covered with soy sauce or other condiments like teriyaki or mayonnaise.

Yaki onigiri – Yaki Onigiri are grilled variants of seasoned onigiri, usually with a meat topping (options include bacon bits, unagi eel).

Mixed Rice Onigirazu – this type has a variety of components, such as vegetables, meat, and even fruit.   Onigirazu – Onigirazu is similar to a rice sandwich with contents like tuna mayonnaise or eel; egg onigiri can also be created with fried eggs.


In this brief guide, we answered the query, “How long does onigiri last?” and discussed how to make onigiri.


  1. Sato, Jun, and Kana Yokokawa. Evaluation of the adequacy of the consume-by date of rice balls sold at convenience stores. Biocontrol Sci, 2014, 19, 165-171
  2. Yeo, Seoungsoon, and Misook Kim. Predictive Growth Modeling of Listeria monocytogenes in Rice Balls and Its Risk Assessment. J Food Qual, 2020 (2020).
  3. Simpson, R., et al. Development of frozen sushi: optimization and shelf life simulation. J Food Process Preserv, 2008, 32, 681-696.
  4. Bergdoll, Merlin S., and A. C. Lee Wong. Staphylococcal intoxications. Foodborne infections and intoxications, 2006.
  5. Kulawik, Piotr, et al. The effect of furcellaran-gelatin edible coatings with green and pu-erh tea extracts on the microbiological, physicochemical and sensory changes of salmon sushi stored at 4 C. Food Control, 2019, 100, 83-91.

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