Can you eat leftover sushi?

In this brief guide, we will answer the question “Can you eat leftover sushi?”. We will also elaborate on how long the sushi leftovers last, what are the ways to consume leftover sushi, and what are the possible nutrients that we can extract from the sushi along with their benefits.

Can you eat leftover sushi?

Yes, you can eat the leftover sushi. It is fine to save raw sushi or cooked sushi leftovers in a refrigerator for up to 24 hours.

What is sushi?

Sushi is a traditional Japanese food generally considered as a seaweed roll that is filled with different edibles like cooked or raw fish, vegetables, and cooked acidified rice. It is majorly served with wasabi, pickled ginger, and soy sauce. 

Sushi is mentioned for the first time in a dictionary compiled in China at the end of the 2nd century AD. However, some authors argue that the origin of sushi was in SouthEast Asia dating back to the 4th century AD (4). Sushi in the 17th century made one of the most popular food items. They took the fish and pressed it between the two layers of rice and salt. In these layers, the fish was allowed to ferment for a specific period.

After that fermenting procedure, it became ready to consume. But as time passed the advancements took place like vinegar became a part of rice that decreased the fermenting rate and enhanced the taste of fish.

But in the late 19th century, the fermentation process was abandoned and people began to consume fresh fish despite that fermented product. This whole process upgraded the eating of ready-made sushi which is being accustomed today.

Sushi is now available as a ready-to-eat (RTE) product in retail stores, normally with a shelf life of 2–3 days after production. Fresh retail sushi typically consists of a complete meal, combining a selection of nigiri and maki sushi with a variety of ingredients (1). 

What are the leftovers of sushi?

If you ordered sushi from a supermarket or in any restaurant, but could not finish it then that leftover portion of sushi can be placed in the refrigerator for a maximum of 24 hours. 

Although the storing of sushi in the refrigerator will bring a change in the texture, taste, and color of sushi such that it will get softened; despite all these reasons it should be safe to consume within 24 hours after its cooking with no harm to the body.

How long can sushi last before spoiling?

The shelf life of any product is predicted by the constituents which are used in the preparation and cooking of that product.

In the same way, ingredients of sushi will indicate the shelf life of sushi and will also prescribe the instructions for storing the sushi concerning its ingredients.

Seafood is more perishable than other high-protein products due to the high postmortem pH and high levels of soluble nitrogen compounds in the tissue. During storage, the spoilage microorganisms grow and produce metabolites responsible for off-flavors. The spoilage of fish is mainly a result of the Gram-negative fermentative psychrotolerant bacteria Pseudomonas sp and Shewanella sp (1). 

The sushi is offered as a chilled product (≤4°C) packed in a plastic tray in a normal atmosphere. The diversity of ingredients includes raw or cooked vegetables and different species of raw fish and raw or cooked seafood combined with rice. The microbiological quality of such combined products is a result of production hygiene (e.g., fileting, slicing and staff hygiene), temperature control and the initial quality of each ingredient (1).

The U.S. Food and Drug Administration, recommends that the leftover sushi should not be kept without a refrigerator for more than two hours and it is also instructed by the FDA not to preserve sushi at room temperature for more than one hour if you are dining the sushi outside and the temperature is high than 90℉ or 32℃ (2).

These FDA instructions truly apply to both types of sushi whether it is raw or cooked such as sashimi and California rolls or tempura respectively.

The duration for storing the raw sushi could be 1 to 2 days or it could be 3 to 4 days when it is cooked, according to the U.S. Department of Agriculture (USDA).

The major point is to preserve the sushi at 40 to 140 degrees Fahrenheit or 4 to 60℃, this temperature condition is termed as a “Danger Zone” where the growth of bacteria can happen that will enhance the risk of foodborne illness.

Some raw fish or sushi are instructed to store up to 2 hours at room temperature while for 1 to 2 days in the refrigerator while the cooked sushi is allowed to store up to 2 hours at room temperature while for 3 to 4 days in the refrigerator.

The nutritional content of sushi

Sushi is considered a good food product for the weight loss journey. Sushi consists of low fat, low cholesterol and high protein content and is rich in vitamins and minerals (3).

Nori is a variety of seaweed that is being used to roll sushi. It contains a variety of nutrients such as phosphorus, calcium, thiamine, iodine, iron, magnesium, sodium, vitamins A, C, and E (4).

The acid added to the rice, usually rice vinegar, contributes to the improved texture and flavor of the sushi. Consumers prefer better rice quality but with low glycemic index. Starchy foods such as rice are consumed once cooked, which improves the digestibility of the starch, but it causes an increase in the glycemic index. However, a study showed that vinegar acts on blood glucose level by decreasing it after ingestion of starch with a 2% of acetic acid solution, in comparison with the normal diet in the absence of vinegar. This study indicated that the acetic acid of the vinegar could prevent the complete digestion of complex carbohydrates, either by accelerating gastric emptying or by increasing glucose uptake by the tissues. Therefore, sushi rice has a lower glycemic index than normal cooked rice without acids (3).

The health benefits of sushi

Some of the health benefits for sushi are as follows (4):

• It is considered a mood stabilizer. That controls mood swings to some extent and regulates the mood.
• It is also a memory booster food item.
• Sushi is rich in omega-3 compounds which is an essential nutrient because the body cannot synthesize this compound on its own, so it is mandatory to consume through a diet such as sushi. Fish contains 4–6% unsaturated fatty acids (omega-3 fatty acids), and in particular, oily fish, such as tuna, salmon, herring and sardine, are a rich source of omega-3 fatty acids.
• Seaweeds used in many sushi rolls are rich in iodine and iron.
• It also plays a significant role in repairing muscles.
• It is also very effective against the formation of wrinkles.
• Appetizers used in sushi preparation, such as ginger and wasabi
• (horseradish), are said to have antibacterial properties, and ginger is claimed also aids digestion and helps reinforce defenses against colds and flu; wasabi is rich in vitamin C.

Conclusion 

In this brief guide, we answered the question “Can you eat leftover sushi?” We also elaborated on how long the sushi leftovers last, what are the ways to consume leftover sushi, and what are the possible nutrients that we can extract from the sushi along with their benefits.

Other FAQs about Sushi that you may be interested in.

Sushi wraps are made up of what seaweed?

Can you freeze sushi rice?

Can you eat California rolls while pregnant?

References

1. Hoel, Sunniva, Anita Nordeng Jakobsen, and Olav Vadstein. Effects of storage temperature on bacterial growth rates and community structure in fresh retail sushi. J App Microbiol, 2017, 123, 698-709. 
2. Safe Handling of Take-Out Foods. 2013. USDA. 
3. Molina, Carla N., Raquel Garzón, and Cristina M. Rosell. Unraveling seasonings impact on cooked rice quality: Technological and nutritional implications for sushi. J Cereal Sci, 2022, 104, 103442.
4. De Silva, Devarahandhi, and Masahiro Yamao. A yen for sushi: an analysis of demographic and behavioural patterns of sushi consumption in Japan. J Foodser, 2006, 17, 63-76.