When it comes to buying and eating shrimp, one of the first things you may notice is the smell. Shrimp naturally has a mild seafood odor, but an excessively strong or fishy smell could indicate the shrimp is not fresh.
Why Does Shrimp Smell?
Shrimp get their signature scent from iodine and sulfur compounds. These compounds are a normal byproduct of living in aquatic environments. A small amount gives shrimp their expected briny aroma.
However, when shrimp is very fresh, the smell is usually mild. An overpowering, pungent odor is often a sign of shrimp that is past its prime.
Factors That Contribute to Shrimp Odor
Several factors can cause shrimp to develop an unpleasant or very strong smell:
- Age – As shrimp ages, oxidative reactions occur in the flesh that result in a stronger scent.
- Storage temperature – Shrimp stored at warmer temperatures will deteriorate and smell more rapidly.
- Freezing method – Shrimp that is poorly frozen or thawed and refrozen can take on odors from ice crystals and freezer burn.
- Preservatives – Sodium tripolyphosphate (STPP) is sometimes used to retain moisture and reduce odor, but it can’t fully prevent unappealing smells in old or mishandled shrimp.
- Bacterial growth – As bacteria multiply, their metabolic byproducts can create noxious odors.
How to Tell if Shrimp is Bad from the Smell
Here are some common descriptions of how shrimp smells when it starts going bad:
- Ammonia/fishy – This is the smell of amino acids breaking down into amines and ammonia gas. It indicates protein decomposition.
- Rotten eggs/sulfur – These scents come from hydrogen sulfide gas. It suggests major spoilage.
- Vinegar/sour – This acidic smell is from fermentation due to lactic acid bacteria. It means the shrimp is past safety limits.
- Rancid/pungent – This comes from oxidation and hydrolysis of fats. It means the shrimp is inedible.
If you smell any of these odors when sniffing raw shrimp, it is best to throw it away. At best, negatively-smelling shrimp will taste unpleasant. At worst, it may contain toxins and dangerous microbes.
How Fresh Shrimp Should Smell
When shrimp is very fresh, the scent should be subtle. There may be light briny, seaweed or iodine aromas. Any hint of ammonia, sourness or pungency means the shrimp is losing freshness.
Here are some signs of fresh-smelling shrimp:
- Mild ocean or seaweed smell
- Clean, neutral odor
- No sour, sweaty, fishy or ammonia scents
- No signs of oxidation like rancidity
If you rub a piece of very fresh, raw shrimp between your fingers, it may smell faintly like the ocean but should not have an offensive odor. Fresh shrimp also smells milder and cleaner when cooked.
Tips to Buy and Store Shrimp to Minimize Odor
You can take several steps when purchasing, handling and storing shrimp to prevent it from developing an overly strong smell:
- Check sell-by and use-by dates at the store.
- Make shrimp one of the last items you select at the market.
- Choose shrimp that is firmly packed, not dripping liquid.
- Select packages on ice, rather than soaked in water.
- Buy individually frozen or IQF shrimp instead of block frozen.
- Keep shrimp very cold during transport.
- Store shrimp immediately at home in a leakproof bag in the coldest part of refrigerator or freezer.
- Use frozen shrimp within about 3 months.
- Use fresh shrimp within 1-2 days of purchase.
- Rinse, pat dry and remove veins to help reduce odor-causing compounds.
- Place used shrimp shells in a tightly sealed bag until you can discard them.
Following safe handling and storage methods can help shrimp retain its freshness and subtle seafood scent for as long as possible.
What Does Shrimp Smell Like When Cooked?
Cooking shrimp intensifies existing odors. Properly cooked fresh shrimp will have a warm, delicately sweet, briny smell. If the cooked shrimp gives off a potent fishy, dirty or rotten odor, it has gone bad and should be discarded.
Here are some typical smells with cooked shrimp:
| Type | Smell Description |
|---|---|
| Very fresh | Warm, sweet, mild ocean aroma |
| Less fresh | Neutral with slight ammonia tinge |
| Spoiled | Pungent, fishy, rotten, sour |
Trust your senses – if cooked shrimp seems off in any way, do not eat it.
How to Safely Handle Raw Shrimp to Reduce Odor
You can help minimize odor-causing bacterial growth and oxidation in raw shrimp with proper handling:
- Wash hands before and after touching raw shrimp.
- Use separate cutting boards and utensils for raw shrimp away from other foods.
- Thaw frozen shrimp sealed in packaging in the fridge, not out at room temperature.
- Rinse thawed or fresh shrimp briefly under cold water.
- Pat shrimp dry with paper towels.
- Devein and peel shrimp, if desired, and discard veins/shells in sealed bag.
- Place shrimp in a clean bowl; season, toss or marinate as desired.
- Refrigerate seasoned shrimp until ready to cook.
- Discard any leftover raw shrimp after cooking.
- Refrigerate cooked shrimp within 2 hours and use within 3-4 days.
Following safe food handling practices helps reduce bacterial growth that causes unpleasant odors and protects against foodborne illness.
Conclusion
It’s normal for fresh shrimp to have a mild ocean or briny scent. A moderate smell alone does not indicate spoiled shrimp, but any hint of ammonia, sulfur, acidity or rancidity means it should be discarded. For the best quality and safety, purchase chilled shrimp before the sell-by date, store it at 32-40°F, and use within 1-2 days. Handle raw shrimp properly to reduce odor-producing bacteria. Trust your senses – if cooked shrimp smells unpleasant or “off,” do not eat it. With proper selection, storage and handling, shrimp can retain its inherent fresh aroma and flavor.