Eating fish that has been left out at room temperature overnight can be risky. Salmon, like any perishable food, can develop bacteria when left out too long. There are a few factors to consider when determining if salmon is still safe to eat after sitting on the counter overnight.
How long can salmon be left at room temperature?
According to the United States Department of Agriculture (USDA), fresh fish should not be left out at room temperature for more than 2 hours. After this time period, bacteria can multiply quickly.
Salmon, like other fish and seafood, has a high risk of developing harmful bacteria faster than other meats when left out. This is because fish has naturally high levels of bacteria present. When kept chilled, this bacteria remains dormant and is not a problem. However, when left out at temperatures between 40°F and 140°F, the “danger zone”, bacteria multiples rapidly.
What types of bacteria grow on fish?
There are two main types of dangerous bacteria that can grow on fish when left out too long:
- Salmonella – Although named after salmon, this bacteria can grow on any type of raw meat, poultry, eggs or fish. Salmonella infection causes symptoms like fever, diarrhea, nausea and vomiting.
- Listeria monocytogenes – This bacteria is found in soil, water and some animals. Eating fish contaminated with listeria can cause a disease called listeriosis with symptoms like fever, muscle aches, nausea and diarrhea.
In addition to these harmful bacteria, fish that is over the recommended 2 hours at room temperature may also start to spoil due to the growth of harmless spoilage bacteria. This can cause the texture and smell of fish to become unpleasant or “off”.
What factors influence bacteria growth?
There are a few key factors that affect how quickly bacteria multiplies on perishable foods like fish:
- Temperature – Warmer temperatures allow bacteria to grow faster. Fish left out overnight at room temperature provides an optimal environment.
- Time – The longer fish is left out, the more time bacteria has to grow. While 2 hours is the recommended max time at room temperature, the risk increases more over 12+ hours overnight.
- Oxygen – Bacteria needs oxygen to multiply. Fish left uncovered overnight is exposed to more oxygen.
- Moisture – Bacteria thrives on moist environments. The moist flesh of fresh fish promotes bacteria growth.
Is it safe to eat raw salmon after being left out?
No, raw salmon that has been left out at room temperature overnight should not be considered safe to eat. Raw fish already carries a higher risk of foodborne illness, and leaving it sitting out gives any naturally present bacteria an ideal opportunity to multiply to dangerous levels. Consuming raw fish that has been left out beyond 2 hours poses a high risk of food poisoning.
Is it safe to eat cooked salmon after being left out overnight?
Cooking salmon before leaving it out eliminates some of the risk, since the high heat from cooking kills bacteria present. However, it does not make the fish completely safe. Harmful bacteria like salmonella or listeria could re-contaminate the cooked fish from contact with hands, utensils, or surfaces. Bacteria present in the air or environment can also begin to multiply on cooked fish left out too long. For highest safety, cooked fish should not be left out more than 2 hours.
What are the signs salmon has spoiled after being left out?
Here are some clear signs that salmon has spoiled and is unsafe to eat after sitting out overnight:
- Bad smell – Fresh salmon has a mild, ocean-like smell. Rancid or rotting odors indicate spoilage.
- Slimy texture – A sticky or slimy texture and mucus-like substance on the flesh.
- Discoloration – Patches of gray, brown or yellow discoloration.
- Dry appearance – Flesh looks dry and shriveled.
Trust your senses – if salmon doesn’t look or smell right after being left out, it is best to discard it.
What are the risks of eating salmon left out overnight?
If you eat salmon that has been sitting at room temperature overnight, these are some of the illnesses you risk contracting:
- Salmonellosis – Caused by salmonella bacteria. Symptoms like diarrhea, fever, abdominal cramps start 12-72 hours after ingestion and last 4-7 days.
- Listeriosis – Caused by listeria bacteria. Begins with fever, muscle aches, nausea and diarrhea. Can become a serious bloodstream infection in those with weakened immune systems.
- Food poisoning – Vomiting and diarrhea that starts 8-24 hours after eating bad fish. Usually resolves on its own within 1-3 days.
Eating spoiled, raw salmon also comes with the general risks of foodborne illness associated with consuming raw fish, like parasites, viruses, toxins and histamine poisoning. The longer fish is left out, the higher the risks.
Who is most at risk from eating spoiled salmon?
While anyone can get sick from eating spoiled fish, some groups have higher risk for serious complications:
- Young children
- Elderly individuals
- Pregnant women and their fetuses
- Those with weakened immune systems
- Those with chronic diseases like diabetes, cancer, kidney disease
These populations are more vulnerable to severe dehydration and bloodstream infections from foodborne pathogens like salmonella and listeria.
How to store salmon safely
To prevent salmon poisoning, it’s important to store fish properly. Follow these salmon storage guidelines:
- Keep raw salmon chilled at 40°F or below until ready to use.
- Thaw frozen salmon in the refrigerator, never at room temperature.
- Place salmon in clean, airtight containers or wrap tightly before refrigerating.
- Use raw salmon within 1-2 days of purchasing.
- Store cooked salmon in shallow, covered containers and use within 3-4 days.
- Do not store raw and cooked salmon together or cross-contaminate.
- When in doubt, throw it out! Don’t risk eating fish that is questionable.
Can you still cook and eat salmon left out overnight?
It is not recommended to eat salmon that has been left out on the counter overnight, whether cooked or uncooked. The safest option is to discard fish that has been sitting at room temperature for more than 2 hours.
However, if the fish still looks and smells normal, some people may choose to cook the salmon thoroughly until it reaches an internal temperature of at least 145°F. This high temperature can destroy bacteria present, but it does not make the fish 100% safe. Consuming fish left out that long still carries a degree of risk.
Conclusion
Salmon left out on the counter overnight enters the danger zone of 40°F – 140°F when bacteria can quickly multiply. Eating salmon after more than 2 hours at room temperature poses a health risk due to potential foodborne pathogens. It is not recommended to consume fish that has been sitting out overnight, whether raw or cooked. Discard fish that is past the recommended holding time, smells odd or looks spoiled. To prevent waste and foodborne illness when handling salmon, always store it properly chilled at 40°F or below. Use ice or refrigeration to keep fresh fish cold if serving it outdoors or at events.