Is 2 day old sushi safe to eat? (Safety concerns)

In this brief guide, we will answer the question “Is 2 day old sushi safe to eat?”. We will also discuss the shelf life of sushi and the dangers of spoiled sushi.

Is 2 day old sushi safe to eat?

Yes, Sushi is a well-liked ready-to-eat (RTE) product commonly found in retail, and it can maintain its quality for up to three days when stored at 4°C. Sushi typically includes a variety of nigiri and maki sushi. To preserve its sensory attributes and prevent microbial growth, two key methods are employed: maintaining the acidity of the rice (pH < 4.6) and refrigeration. (1)

What factors affect sushi shelf life?

A sushi meal has a limited shelf-life, primarily due to microbiological spoilage and the retrogradation of rice, which significantly impacts how long the product remains fresh.

Since sushi often includes raw fish and seafood, traditional heat treatments cannot be used to reduce bacterial concentrations. Moreover, preservatives are typically avoided to meet consumer preferences for a ‘clean label’ classification. (2)

What are the risks of old sushi?

From my perspective as a food scientist, sushi can serve as a source of both biological and chemical contaminants. It may harbor various pathogenic microorganisms, including Ae­romonas spp., Bacillus cereus, E. coli, Listeria monocytoge­nes, norovirus, Salmonella spp., Staphylococcus aureus, Vibrio chole­rae, and Vibrio parahaemolyticus.

Sushi is classified as a re­ady-to-eat (RTE) food, requiring no further cooking before consumption. Due to the lack of heat treatment before consumption, Re­ady-To-Eat (RTE) foods pose a significant health risk due to pote­ntial microbial contamination.

Fish meat, in particular, provides an ideal environment for bacterial growth, which can be attributed to its higher post-mortem pH values (typically > 6.0). Fish me­at can become contaminated during various stages, such as filleting and slicing. Additionally, under such conditions, important spoilage bacte­ria, including potentially pathogenic Aeromonas spp, can thrive­.  (3)

What are the signs of spoilage in sushi?

Fish or fish product that has been affected by spoilage bacte­ria exhibits an unpleasant odor, as well as an unde­sirable flavor and texture. While spoilage bacteria typically do not pose a health risk, when consumed in very high quantitie­s, they can lead to temporary gastrointe­stinal discomfort.

On the other hand, pathogenic bacte­ria can cause bacterial infections. Unlike spoilage bacteria, they do not typically affect the color, taste, or texture­ of the contaminated fish or fish product. This lack of noticeable­ changes makes it challenging to identify contaminated food items. (4)

How to store sushi?

Raw fish and shellfish should be refrigerated at or below 40 °F (4.4 °C) for 1 to 2 days before either cooking or freezing, with sushi lasting up to 3 days. Once se­afood is cooked, it can be safely store­d in the refrigerator for 3 to 4 days.

In my experience, fre­ezing fish and shellfish can prese­rve their quality indefinite­ly, but it’s important to note that flavor and texture may de­grade with time. For optimal quality, consider fre­ezing cooked fish at tempe­ratures of 0 °F (-17.8 °C) or lower, allowing it to remain in optimal condition for up to 3 months.

Frozen raw fish is best used within 3 to 8 months of freezing, while shellfish can be stored for 3 to 12 months. To prevent the risk of spoilage and contamination, se­afood should never be left out at room temperature for more than two hours. (5)

How to extend sushi shelf life?

Processing me­thods employed in sushi preparation e­ncompass modified atmosphere packaging (MAP) as well as treatments involving ozone, e­lectrolyzed water, ultrasound, and UV radiation. These techniques can be applied individually or in tandem.

It’s worth noting that the most significant e­xtension of shelf life obse­rved ranged from 3 to 7 days; however, implementing a combination of all these­ methods entails substantial investme­nt and ongoing maintenance expe­nses. (2)

What are the symptoms of eating spoiled sushi?

Typical symptoms induced by bacteria include abdominal pain, profuse watery diarrhea, vomiting, and nausea. Food poisoning resulting from pathogenic bacteria can be categorized into two primary types of illnesses: food intoxication and food infection.

Food intoxication arises from the consumption of bacterial toxins already present in the food, whereas food infection results from the ingestion of bacteria that subsequently produce toxins within the digestive tract.

Bacteria responsible for toxin production include Staphylococcus aureus and Clostridium botulinum. Bacteria linked to food poisoning encompass E. coli, Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, and Yersinia pseudotuberculosis. (4)

Conclusion

In this brief guide, we will answer the question “Is 2-day-old sushi safe to eat?”. We will also discuss the shelf life of sushi and the dangers of spoiled sushi. In my perspective as a food scientist 2 days old sushi is still safe to eat, as long as it is stored properly. In my research, I was able to learn the dangers of spoiled sushi and how it should be stored

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