How Long Can Raw Fish Sit Out? The Shocking Truth You Need to Know!

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Unless you are an experienced fishmonger, it can be hard to know how long raw fish can sit out before it becomes unsafe to eat. Whether you are a sushi lover or simply enjoy cooking fresh seafood at home, you need to understand the risks and safety measures that come with handling and preparing raw fish.

The truth is, consuming improperly stored or prepared raw fish can result in serious health consequences, including foodborne illness caused by bacteria, viruses, parasites, and toxins present in fish. This is particularly true when dealing with high-risk species such as tuna, salmon, mackerel, and shellfish.

“Preventing food poisoning starts with safety practices in the kitchen.”

Thus, if you want to avoid getting sick from eating raw fish, it’s crucial that you pay attention to proper storage techniques, temperature control, and hygiene standards. Knowing how long it’s safe to leave your fish unrefrigerated, for instance, can make all the difference between a delicious meal and a dangerous health hazard.

In this article, we will explore the shocking truth about the risks of eating raw fish that has been left out too long, plus practical tips on how to store and handle it safely. Read on to learn more!

What Happens to Raw Fish When it Sits Out?

Raw fish is a popular ingredient in many types of cuisine, including sushi, ceviche, and poke. However, like all raw meat, raw fish must be handled with care to prevent the growth of harmful bacteria that can cause illness. One question often asked about raw fish is: how long can it sit out before it goes bad? To answer this question, we need to look at some of the changes that occur in raw fish as it sits out.

Microbial Growth on Raw Fish

Raw fish provides an ideal environment for bacterial growth because it is moist, nutrient-rich, and has a neutral pH. As soon as raw fish is harvested or processed, bacteria from the surrounding environment begin to colonize its surface and interior. These bacteria include both harmless ones and potentially pathogenic ones, such as Vibrio, Salmonella, and Listeria.

The rate of microbial growth on raw fish depends on several factors, such as temperature, oxygen level, humidity, and acidity. According to the United States Food and Drug Administration (FDA), the optimal temperature range for raw fish storage is between 32°F and 38°F (0°C to 3.3°C) since these temperatures slow down bacterial growth. At room temperature (around 70°F or 21°C), the FDA advises consuming raw fish within two hours of being left unrefrigerated.

Changes in Texture and Appearance

As bacteria multiply on raw fish, they consume its nutrients and produce waste products that alter its texture and appearance. The flesh may become slimy, discolored, mushy, or oily due to the breakdown of proteins, lipids, and other molecular components. These changes not only affect the quality and taste of the fish but also make it more susceptible to spoilage and contamination.

The texture and appearance of raw fish can also be affected by other factors such as exposure to air, light, or heat. For example, if raw fish is left uncovered, it may absorb odors and flavors from its surroundings that can mask or alter its natural taste. Moreover, if raw fish is subjected to high temperatures (above 40°F or 4.4°C), the enzymes in its muscle tissue may start to denature, causing the proteins to break down and weaken the structure of the flesh.

Loss of Nutritional Value

In addition to changes in texture and appearance, raw fish that sits out for too long may lose some of its nutritional value. This is because many of the vitamins, minerals, and essential fatty acids found in raw fish are sensitive to environmental factors such as light, temperature, and oxidation. For instance, the omega-3 fatty acids that are abundant in certain types of raw fish, such as salmon and tuna, can degrade quickly when exposed to oxygen, leading to a decrease in their health benefits over time.

Furthermore, consuming contaminated raw fish can result in foodborne illnesses that can cause diarrhea, vomiting, abdominal pain, fever, and even death in severe cases. These illnesses can be especially dangerous for pregnant women, children, older adults, and people with weakened immune systems.

Formation of Histamines

An additional risk associated with consuming raw fish that has been left unrefrigerated is the formation of histamines. Histamines are chemical compounds that are produced by bacteria as part of their metabolism. In humans, histamine can trigger an allergic response that causes symptoms such as itching, hives, swelling, and difficulty breathing. They are responsible for a type of food poisoning known as scombroid poisoning, which can occur after consuming certain types of fish such as mackerel, tuna, and sardines that have been stored at improper temperatures and have developed high levels of histamine.

“When food is left out for long periods of time — be it in a restaurant or market setting — significant amounts of histamine can accumulate, leading to symptoms of scombroid poisoning… Watch for “rotten egg,” ammonia, or even tobacco-like smells emanating from the flesh of the fish.” – Dr. Katie Boekhoff

Raw fish should ideally be consumed as soon as possible after being harvested or purchased and kept refrigerated at all times until ready to use. If raw fish is left unrefrigerated for more than two hours, it should be discarded to avoid the risk of foodborne illness. It is also essential to follow proper hygiene practices when handling raw fish to prevent cross-contamination with other foods or surfaces. By taking these precautions, you can enjoy the health benefits and delicious flavor of raw fish without endangering your health.

Why is it Dangerous to Eat Raw Fish That’s Been Left Out?

If you’re a fan of sushi or ceviche, then you know how delicious raw fish can be. However, if you leave raw fish out at room temperature for too long, you run the risk of developing foodborne illnesses or ingesting harmful toxins.

Foodborne Illnesses

Bacteria, viruses, and parasites are some of the culprits responsible for foodborne illnesses that affect humans who consume raw fish that’s been left out. According to the U.S. Food and Drug Administration (FDA), most seafood-borne illnesses stem from consuming bacteria such as Vibrio, Salmonella, or Listeria. These microorganisms can cause gastrointestinal symptoms like nausea, vomiting, diarrhea, fever, abdominal pain, and in severe cases, complications like dehydration, sepsis, meningitis, miscarriage, or death. In addition, individuals with weakened immune systems, pregnant women, young children, and older adults represent high-risk groups that should avoid eating raw fish entirely or ensure its proper storage and preparation. Therefore, the FDA recommends storing raw fish at a temperature below 40°F and cooking it to an internal temperature of 145°F before consuming it.

Ingestion of Toxins

Anisakids are worms that infect various marine creatures like fish, squid, or octopus, and their larvae can survive in uncooked seafood. If ingested by humans, these larvae can latch onto gastric wall, causing severe inflammation and allergic reactions. Symptoms may vary but can include stomach pain, nausea, and vomiting. Furthermore, prolonged exposure to higher levels of histamine produced by bacterial decomposition during storage can lead to scombroid poisoning, commonly referred to as “fish poisoning.” This illness typically occurs within 30 minutes to an hour of eating and can cause flushing, palpitations, headache, cramps, diarrhea, or respiratory distress. To prevent these toxic reactions, the FDA recommends purchasing seafood from reputable vendors and consuming it within two hours of purchase if stored at room temperature (above 90°F), or within four hours if chilled (at or below 40°F).

Enjoying raw fish that’s been left out can increase one’s risk of developing foodborne illnesses caused by bacterial contamination or parasites such as Vibrio, Salmonella, Listeria, or Anisakis, leading to gastrointestinal symptoms like nausea, vomiting, diarrhea, fever, and in severe cases, complications like dehydration, sepsis, meningitis, miscarriage, or death. Moreover, ingesting harmful toxins produced by bacterial decomposition in unrefrigerated or poorly handled seafood can lead to scombroid poisoning or allergic reactions that may require medical attention.

How Long Can Raw Fish Be Left Out Before it Becomes Unsafe to Eat?

Temperature and Humidity

The duration of time that raw fish can sit out at room temperature before becoming unsafe to consume will depend greatly on the surrounding temperature and humidity conditions.

In general, the US Food and Drug Administration (FDA) recommends that perishable foods should not be left outside of the refrigerator for more than two hours. If the temperature is above 90°F, then the maximum safe duration decreases to only one hour.

Fish is a highly perishable food item, meaning it has a high likelihood of spoiling due to bacterial growth if left out in an unsuitable environment. At warmer temperatures, bacteria will multiply much faster resulting in foodborne illness caused by the harmful microorganisms present in the contaminated fish.

Type of Fish

Different types of fish also impact how long raw fish can sit out safely before going bad.

Fatty fish, such as salmon or tuna, contain Omega-3 fatty acids which are good for your health but make them more susceptible to deterioration. These fatty acids are vulnerable to oxidization and turn rancid quickly when exposed to air. Therefore, leaving these fish out for too long may cause them to develop a sour taste and unpleasant smell.

Fishes with low oil content like cod or halibut, readily release moisture from their flesh causing dehydration and subtle flavor shifts when exposed to dry environments. This makes them relatively less risky to leave out compared to oily fishes. However, it’s important to still follow guidelines around storage times and refrigeration processes despite the type of fish you have purchased.

“According to the United States Department of Agriculture (USDA), any cooked seafood leftovers worth eating should be consumed within three to four days of refrigeration.”

Therefore, while different factors can affect the time raw fish may be safely left out before spoiling, it is always necessary to take appropriate steps towards storage and handling whenever you buy or prepare seafood.

  • Keep your fish cold – Store it immediately in a sealed container on ice at 40°F or lower. Avoid leaving fish uncovered for extended periods
  • Plan ahead — Thawing frozen fish in advance will prevent unnecessary delay in cooking times, ensuring that they spend as little time sitting outside
  • Cook properly – Cook to an internal temperature of 145°F (63°C) making sure it’s reached in various parts of the food. This heat treatment would kill bacteria if present
  • Refrigerate leftovers within two hours of preparation- Follow safe cooling procedures by dividing up dishes into small portions, allowing them to cool down promptly in the refrigerator

What are the Signs of Spoiled Raw Fish?

Raw fish is a delicious and healthy addition to any meal. However, it’s important to be aware of the signs that raw fish has spoiled because eating contaminated fish can cause food poisoning, which results in symptoms like nausea, vomiting, diarrhea, and fever.

Unpleasant Odor

If raw fish smells bad, it’s a clear sign that it has started to spoil. Fresh raw fish should have a neutral or slightly oceanic scent without any hint of ammonia. On the other hand, spoiled fish emits an unpleasant odor similar to rotting eggs or sulfur due to bacterial breakdown of proteins into various organic compounds such as trimethylamine oxide, histidine, cadaverine, and putrescine.

“Fishy” odors typically indicate old fish but non-fishy aromas could mean spoiled fish – for example sourness, mustiness, or ammonia-like smells.

Foul smells may also emanate from normal physiologic decomposition processes in some species of raw fish including Tuna, Amberjack, Mackerel, and Mahi-Mahi. These fish naturally contain higher amounts of purines that break down into uric acid which creates low-level inflammation when exposed to air.

Discoloration and Slimy Texture

Spoiled raw fish often becomes discolored and develops a slimy texture. The flesh might appear duller than usual or present patches with different colors (depending on the type of fish). In general, fresh fish should be moist but not slimy to the touch. A slimy feeling could stem from gel formation caused by excess bacteria breaking down amino acids or fatty acids producing exopolysaccharides that form slime layers. Another reason for the slippery sensation is mucus secretion from the fish’s skin when under stress, inflammation, or infection.

“As bacteria incubate in raw fish over time, they produce mucin proteins found in slime.” -Live Science

Presence of Mold or Bacteria

Mold and bacterial growth are visible indicators that raw fish has gone bad. Some mold species look like furry white, black, green, or gray coats on top of the fish flesh or gills. Whereas bacterial colonies appear as small spots or specks covering large areas of the meat surface. The US Food and Drug Administration warns consumers to avoid raw fish contaminated with Listeria monocytogenes, E.coli, Salmonella, Vibrio parahaemolyticus, and other pathogens. Additionally, parasites such as roundworms or tapeworms may infect some raw fish varieties, especially those intended for sushi-grade consumption.

“Fish can also harbor parasites – this will not be evident in its odor/flavor, but instead on the visual cues, like patches on the flesh.” -Extreme Cuisine with Jeff Corwin

The rule of thumb for raw fish storage depends on how fresh it was upon purchase and handled afterward. Fish bought directly from a fisherman should be sold alive, gutted, and chilled immediately before being consumed within a day. If buying fish from a store, always check the expiration date label assigned by the vendor and follow proper refrigeration guidelines specific to the type of fish you know best.

How to Properly Store Raw Fish to Prevent Spoilage?

If you want to keep your raw fish fresh for longer, it is crucial to store it properly while minimizing the risk of spoilage. While seafood can be a healthy and tasty addition to any meal, it requires more care than other types of meats because it spoils quickly.


The ideal temperature range for refrigerating raw fish should be between 32°F-38°F (0°C-3°C). Keeping the fish at this temperature slows down bacterial growth that causes food spoilage. When you purchase fish, place it immediately in a plastic bag and seal tightly before keeping it in the refrigerator. Never leave the fish out even for few minutes after purchasing, this increases the chances of bacteria growth on the fish.

You should also avoid storing raw fish with other ready-to-eat foods such as fruits and vegetables in the fridge. This prevents contamination from occurring which poses health risks. Handle raw fish safely by washing hands, utensils, cutting boards, work surfaces and any equipment used to handle it thoroughly after use.


To extend the shelf life of raw fish, it is essential to freeze it correctly. Freezing fish helps reduce enzyme activity that promotes spoilage. Keep the raw fish in an airtight container or bag after wrapping it in a moisture-proof cover to prevent freezer burn or ice crystal formation. This process should minimize the loss of quality during long-term storage.

This article states The National Fisheries Institute recommends freezing fish below -31F (-35C) for 15 hours or until solid to ensure all harmful parasites are destroyed reducing any chance of causing illness upon eating.

Proper Packaging

The packaging method plays a vital role in keeping raw fish fresh during storage. Use a moisture-proof material such as butcher or wax paper to wrap your fish before placing it in an airtight container or plastic bag before placing in the fridge or freezer.

According to Seafood Health Facts, You can expect unopened vacuum-sealed containers of fish from Packaging companies such as Bumble Bee, StarKist, and Chicken of the Sea that have been kept refrigerated to last up to 2 years, While after being opened they tend to only last between 3-4 days without proper handling.

“The best way I’ve found to store seafood is on a bed of ice wrapped tightly with cling film. This way, you keep it at a chilled temperature while still protecting sensitive flesh.” – Eric Ripert

Can You Eat Raw Fish That’s Been Left Out If You Cook It?

Effectiveness of Cooking

Cooking raw fish can kill harmful bacteria that may have grown on it while it was left out. However, this does not mean that cooking the fish will necessarily make it safe to eat.

According to the USDA, a foodborne illness called scombroid poisoning can occur when certain species of fish are improperly stored at temperatures above 60°F (15°C). This type of poisoning occurs when bacteria converts histidine in the fish to histamine, a compound which can cause symptoms such as flushing, sweating, headache, and gastrointestinal distress. Cooking the fish will not eliminate any histamine already present in the flesh.

The Centers for Disease Control and Prevention (CDC) also warns that cooking contaminated fish may not always be effective in killing all harmful bacteria. The best way to avoid getting sick is to ensure that the raw fish you consume has been properly handled and cooked.

Risk of Cross-Contamination

If raw fish has been left out for too long, there is an increased risk of cross-contamination with other foods or surfaces in the kitchen. Bacteria from the fish can easily spread to other areas if proper sanitation practices are not followed.

The USDA recommends that raw fish should never sit out at room temperature for more than two hours, or one hour if the air temperature is above 90°F (32°C). Additionally, the agency advises against tasting raw seafood before it is fully cooked.

To reduce the risk of cross-contamination, it is important to follow basic food safety principles such as washing hands thoroughly before handling food, using separate cutting boards for different types of food, and disinfecting work surfaces regularly.

“Cross-contamination is a serious concern when handling raw fish. Taking steps to prevent this can help reduce the risk of foodborne illness.” – The National Institutes of Health

While cooking raw fish can kill harmful bacteria that may have grown on it, it may not always be effective in eliminating all risks of foodborne illness. To stay safe, it is important to ensure that fish is stored and handled properly to avoid contamination.

Frequently Asked Questions

How long can raw fish sit out at room temperature?

Raw fish should not sit out at room temperature for more than 2 hours. This is because bacteria can grow rapidly at temperatures between 40°F and 140°F. If the room is above 90°F, the time limit is reduced to 1 hour. It’s important to keep raw fish cold until you’re ready to cook it.

What happens if you eat raw fish that has been left out too long?

If you eat raw fish that has been left out too long, you risk getting food poisoning. The bacteria that grow on raw fish can produce toxins that can make you sick. Symptoms of food poisoning from raw fish include nausea, vomiting, diarrhea, and abdominal pain. In severe cases, it can lead to hospitalization or even death.

Can raw fish be left out overnight?

No, raw fish should not be left out overnight. The risk of bacteria growth increases after 2 hours at room temperature, and leaving raw fish out for an extended period of time can increase your risk of food poisoning. It’s important to keep raw fish refrigerated until you’re ready to use it.

What are the signs that raw fish has gone bad?

If raw fish has gone bad, it will have a strong, unpleasant odor. The flesh may appear slimy or discolored, and it may have a cloudy or milky appearance. If you notice any of these signs, do not eat the fish. Consuming spoiled fish can cause food poisoning and other health problems.

How should raw fish be stored to prevent spoilage?

Raw fish should be stored in the refrigerator at a temperature of 40°F or below. It’s important to keep the fish in its original packaging or wrap it tightly in plastic wrap to prevent air from getting in. If you’re not planning to use the fish within 2 days, you can freeze it. When thawing frozen fish, do so in the refrigerator or under cold running water.

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