How long can cooked rice stay in the fridge?

In this brief guide, we will answer the query, “How long can cooked rice stay in the fridge?” and will discuss signs of detecting bad rice.

How long can cooked rice stay in the fridge?

Cooked rice can stay for four days in the fridge and up to 8 months in the freezer.

Shelf life of dry rice

The shelf life of dried or uncooked rice varies. White rice has a longer shelf life than brown rice, even though there are numerous varieties of rice.

In storage, the chemical composition and industrial quality of the grains can be affected by the storage time, system and temperature, as well as by the grain’s physical integrity. Due to the grain aging process, changes in the activities of endogenous enzymes occur, which cause structural changes in cell membranes and in the main constituents: carbohydrates, lipids and proteins (1).

There is more fat and oil in brown rice since it hasn’t been processed. White rice, on the other hand, is less likely to get rancid than brown rice. Although both varieties of rice are considered shelf-stable when dried, they may be kept at room temperature.

 The lipid content of brown rice is almost four times higher than that of white rice. Consequently, the storage stability of brown rice could be lower due to lipid rancidity, which results in off-flavor and poor consumer acceptability. Rancidity mainly occurs in two major ways: hydrolytic and oxidative. Hydrolytic rancidity refers to the hydrolysis of triglycerides to release free fatty acids, which are more sensitive to oxidation than the fatty acid moieties of glycerol esters. And oxidative rancidity is the autoxidation of lipids with the generation of volatile short-chain aldehydes and ketones that are a response for off-flavor, such as malondialdehyde (2).

On the other hand, white rice undergoes chemical changes during storage. There is a decrease in the amounts of lipids and proteins and an increase in the fiber content. According to studies, the lipids in rice grains are stable in the spherosomes of an intact cell, however, when the cell membrane is damaged, lipid hydrolysis is triggered by the action of lipases, which are enzymes that hydrolyze lipids. The study showed that storage did not significantly influence the chemical composition of brown rice. Amounts of proteins, lipids and fibers did not change significantly during 8 months storage, mainly due to the absence of the polishing process, which can cause changes in chemical composition of rice grains (1).

The following table lists the shelf life of several kinds of rice, according to the USDA:

·         The shelf life of white rice is two years, when packaging remains unopened. After opening, rice may be kept for one year at room temperature.

·         For brown rice 3–6 months after manufacturing. Depending on the processing, an unopened packaging of brown rice may be stored for one year.

It’s important to keep in mind that freezing and refrigerating these products may greatly increase their shelf life.

How can you tell if your rice has gone bad?

Expiration dates, often known as “best-by” or “use-by” dates, are commonly seen on shelf-stable items. However, if there are no symptoms of degradation on the product’s packaging, they may be eaten beyond that date.

To tell whether dry rice has gone bad, it’s a rather simple process

To avoid mold development, look for any symptoms of decomposition in the box such as rips, cracks, bugs, or wetness. You may also search for discoloration, a rotten or weird scent, or an oily texture when it comes to brown rice. It’s best to keep your rice in a cool, dry location like your pantry or kitchen cupboard if you want to keep its quality as long as possible. After you’ve opened it, you may keep it in an airtight container. Bugs and dampness will also be kept at bay as a result.

Shelf life of cooked rice

Cooked rice, unlike dried rice, has a consistent shelf life regardless of the kind of rice used. If stored properly in the refrigerator, cooked rice may survive up to a week while retaining its original taste, texture, and quality. Cooked rice may be stored in the freezer for up to eight months. The USDA recommends a storage time of 4 to 6 days for cooked rice in the refrigerator and of up to 6 months in the freezer.

How do you tell if the rice you’ve cooked has gone bad?

The cooked rice is highly perishable due to its high water activity. It is easily affected by microorganisms which ferment the rice starch under room temperature. Cooked rice is even more easily and dangerously affected by microbes which are responsible for food poisoning and food infection. Rice is a low acid food and therefore must be refrigerated, frozen or sterilized after cooking, to prevent microbial growth. When cooked rice is stored, gelatinised starch recrystallizes to an extent depending on time, temperature and moisture content and leads to changes in rice sensory properties (3). You can tell if your cooked rice has gone bad in a few ways.

·         Take a whiff first. Expired rice, in contrast to freshly cooked rice, has a weird or unpleasant odor.

·         Second, pay attention to how it feels. Expired rice might become sticky or mushy instead of fluffy and airy.

·         Finally, inspect the rice for mold, which may be seen as green, blue, or black patches on the grain.

Keep an eye out for any of these indicators of deterioration, and throw out your rice immediately.

Expired rice poses several health risks

Mycotoxins, which may cause food poisoning, can be found in fungus and mold in expired rice. Vomiting, nausea, and stomach discomfort are all associated with mycotoxin ingestion, as are convulsions, coma, an elevated risk of cancer, and a compromised immune system. The production and occurrence of mycotoxins differ depending on the geographic and climatic conditions; however, these toxicants can never be removed completely from the food supply and cannot be totally removed by cooking methods. A study showed that cooking rice could reduce only 18% of the initial toxin present in the rice (4).

Furthermore, mold infection in dry rice might lower the nutritious value of the grain as well. Remember that even if the rice is still fresh, inappropriate food handling of cooked rice may raise the risk of food poisoning from Bacillus cereus, which commonly causes stomach pains, diarrhea, and vomiting. In rice, Bacillus cereus is a microbe that may be resistant to cooking. As a result, bacteria may create toxins if rice is not refrigerated or frozen within two hours after cooking. 

How is food illness caused by reheated rice?

Bacillus cereus spores, which may cause food poisoning, can be found in uncooked rice. Even after the rice has been cooked, the spores may live. Rice spores may develop into bacteria if left standing at room temperature. Toxins (poisons) produced by these bacteria may induce vomiting and diarrhea. For every hour that cooked rice is kept at room temperature, germs and toxins are more likely to grow.

B. cereus can multiply under temperature conditions as low as 38°F (refrigeration temperature) in foods that contain rice and have been cooked or subjected to treatments that do not produce commercial sterility. B. cereus produces diarrhoeal or emetic foodborne toxins when the consumer eats food in which a sufficient number of cells have grown. These circumstances mean that every year many outbreaks of intoxication or intestinal problems related to this microorganism are reported (5).

Food poisoning may cause a wide range of symptoms

This bacterium may cause nausea, vomiting, and diarrhea within 1 to 5 hours after eating rice contaminated with Bacillus cereus bacteria. The symptoms are modest and normally only linger for a day or two.

Serving rice in a safe manner

·         When serving rice, it’s best to do it immediately after it’s done cooking.

·         If that isn’t an option, make sure the rice is as cold as possible after cooking (ideally within 1 hour).

·         Only keep rice in the fridge for one day before reheating.

·         When reheating rice, make sure it’s boiling all the way through before serving.

·         Reheating rice more than once is a bad idea.

Other FAQs about Rice that you may be interested in.

What can I substitute for cilantro in rice?

How Much Brown Rice is per Person

How long does rice last in the fridge?

Can you use rice as a pie weight?

Conclusion

In this brief guide, we answered the query, “How long can cooked rice stay in the fridge?” and discussed signs of detecting bad rice.

References

1. Scariot, Maurício Albertoni, et al. Effect of drying air temperature and storage on industrial and chemical quality of rice grains. J Stored Prod Res, 2020, 89, 101717.
2. Wang, Hao, et al. Effect of high pressure processing on rancidity of brown rice during storage. LWT, 2018, 93, 405-411.
3. Yu, L., et al. Review of the effects of different processing technologies on cooked and convenience rice quality. Trend Food Sci Technol, 2017, 59, 124-138.
4. Sakuma, Hisako, et al. Estimated dietary exposure to mycotoxins after taking into account the cooking of staple foods in Japan. Toxins, 2013, 5, 1032-1042.  
5. Rodrigo, Dolores, Cristina M. Rosell, and Antonio Martinez. Risk of Bacillus cereus in relation to rice and derivatives. Foods, 2021, 10, 302.