How to know if shrimp is spoiled

In this brief article, we will have a look at ways to differentiate between fresh and spoiled shrimp. We will also discuss the dangers of consuming spoiled shrimp, as well as some ways to store your shrimp for the longest possible shelf life.

How to know if shrimp is spoiled?

To determine if your shrimps are spoiled you can check their appearance, color, smell and expiration date. Here, you can find some signs that could help you to determine if your shrimps are spoiled or not:

1. Appearance of the shell: The shell on fresh raw shrimp is firm and glossy, appearing closely attached to the body. If the shell is loose, discolored, or has spots on it, the shrimp has gone bad and should be discarded.

Moreover, if the shell has a gritty, yellowish appearance, it might be because of the use of chemicals such as sodium bisulfate to bleach the shells in an effort to mask the age of the shrimp.

Fresh shrimp has a translucent and glossy shell without any moldy spots or discoloration. 

2. The eyes: Check the eyes if the shrimp still has the head on. Fresh shrimp will have prominent clear eyes. If the eyes are sunken or opaque, it might be spoiling.

Another way to tell is by touching the shrimp. It should be firm and smooth. If it feels slimy to the touch, it might be spoiled. 

3. Color: The body of the shellfish itself is usually white or pinkish/peach in color and appears to be slightly translucent, turning pink or reddish when cooked. 

If you notice any discoloration or moldy spots, your shrimp might not be fit for consumption.

You should be very careful with molds as they produce dangerous mycotoxins that can make you very sick (1). You should never eat spoiled shrimp!

4. Smell: Fresh raw shrimp has a mild salty scent, resembling seawater. If you detect a foul and rancid smell resembling that of ammonia, your shrimp has gone bad, because the smell is from the microbes growing on the fish.

5. Expiration date: If you buy your shrimp packaged, the packaging will have a label on it telling you how much longer it should be edible in the form of a “best before” or “use by” date. If that date has passed, it is best to get it out.

Can you get sick from eating spoiled shrimp?

Yes, eating spoiled shrimp can lead to foodborne illnesses, as they can harbor harmful pathogens that can make you very sick (2-5). 

Some of the dangers and symptoms associated with consuming spoiled shrimp include:

• Bacterial infections: Spoiled shrimp may be contaminated with various bacteria that can cause infections. For example:

• Vibrio parahaemolyticus: This bacterium can cause symptoms such as watery diarrhea, abdominal cramps, nausea, vomiting, fever, and chills (2-3).

• Salmonella: Ingesting shrimp contaminated with Salmonella can result in symptoms such as diarrhea, abdominal pain, fever, and vomiting (4).

• Listeria monocytogenes: This pathogen can cause listeriosis, which may lead to symptoms like fever, muscle aches, nausea, diarrhea, and, in severe cases, meningitis or blood infections (4).

• Viral infections: While less common, some viral pathogens can contaminate shrimp and cause illnesses. One example is norovirus, which can lead to symptoms including diarrhea, vomiting, nausea, stomach pain, and dehydration (5).

• Histamine poisoning: Spoiled shrimp may contain high levels of histamine due to bacterial contamination. Ingesting such shrimp can result in histamine poisoning or scombrotoxic fish poisoning (6). 

Symptoms may include flushing of the face, headache, sweating, nausea, vomiting, and diarrhea (7).

• Allergic reactions: Some individuals may be allergic to shrimp or certain proteins found in shrimp (8). 

Eating spoiled shrimp may increase the risk of exposure to these allergens, leading to allergic reactions that can range from mild symptoms (e.g., itching, hives) to severe ones such as difficulty breathing or anaphylaxis (9).

It is worth noting that the specific symptoms experienced can vary depending on the individual’s overall health, the amount and type of pathogens present, and the extent of the contamination.

What should you do if you suspect you have eaten spoiled shrimp?

If you have eaten spoiled shrimp and suspect food poisoning or any adverse reaction, it is important to follow these recommendations:

1. Monitor your symptoms: Pay attention to any signs of foodborne illness or allergic reaction, such as nausea, vomiting, diarrhea, abdominal pain, or difficulty breathing (10). If symptoms are severe or persist, seek medical attention immediately.

2. Stay hydrated: Drink plenty of fluids, such as water or electrolyte solutions, to prevent dehydration caused by diarrhea or vomiting (11).

3. Rest and take care of yourself: Allow your body time to recover by getting enough rest. Stick to bland, easily digestible foods once your appetite returns.

4. You should always ensure that you handle and store seafood properly, following the recommended guidelines for safe food preparation and storage (12).

Finally, remember that prevention is always better than cure!

What is the shelf life shrimp?

The shelf life of shrimp can vary depending on various factors, including the type of shrimp, how it was handled, and whether it was properly stored (13). 

The following table summarize the approximate shelf life of different types of shrimp under proper storage conditions:

Shrimp Type	Refrigerated Shelf Life	Frozen Shelf Life
Fresh Shrimp	1 to 2 days	Not applicable
Cooked Shrimp	3 to 4 days	Several months (if properly frozen)
Pre-packaged Shrimp	Before “sell-by” or “use-by” date	Several months (if properly frozen)

Please note that these are general guidelines, so it is always important to inspect the shrimp for signs of spoilage before consuming it.

How to store your shrimp for the longest possible shelf life?

Fresh shrimp has a rather short shelf life so it is best to buy it fresh and use it as soon as possible. However, there are some ways to improve the shelf life of your shrimp. Here are a few things you can do:

1. Refrigeration: Refrigeration can improve the shelf life of your raw shrimp, making it last up to three days in the fridge if it is left with the shell on, and two days if it has been shelled. If cooked, it can be stored in a refrigerator for up to four days before it starts to rot.

Refrigerate in a sealable container to avoid getting the aroma into another container in your fridge, and put it in the coldest spot in your fridge.

2. Freezing: Frozen shrimp can last up to a week if frozen properly. Make sure you use a vacuum sealed freezer bag to preserve the flavor, and to get the longest shelf life possible. Moreover, use it within 24 hours of thawing as it will go bad afterwards.

3. Canning: When canned, shrimp can last very long, up to eight months on the shelf. You can buy canned shrimp from your local supermarket. Bear in mind that it will not be as flavorful as fresh shrimp.

Conclusion:

In this brief article, we have had a look at ways to differentiate between fresh and spoiled shrimp. We also discussed the dangers of consuming spoiled shrimp, as well as some ways to store your shrimp for the longest possible shelf life.

References:

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2. Sujeewa AKW, Norrakiah AS, Laina M. Prevalence of toxic genes of Vibrio parahaemolyticus in shrimps (Penaeus monodon) and culture environment. Int Food Res J [Internet]. 2009 [cited 2023 Jun 9];16(1):89–95. Available from: http://mymedr.afpm.org.my/publications/46361 

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6. Amin AN, Ahemd AM, Ahmed OM. Chemical and bacteriological risks of shrimp and clams (Gandofly) from suez gulf. Food Res [Internet]. 2021 Jun 1 [cited 2023 Jun 9];5(3):281–8. Available from: https://www.semanticscholar.org/paper/Chemical-and-bacteriological-risks-of-shrimp-and-Amin-Ahemd/077d1c1edb4da76ca583059aa23c428f94191873 

7. Hungerford JM. Scombroid poisoning: A review. Toxicon [Internet]. 2010 Aug 15 [cited 2023 Jun 9];56(2):231–43. Available from: https://www.sciencedirect.com/science/article/abs/pii/S0041010110000450 

8. Pascal M, Grishina G, Yang AC, Sánchez-García S, Lin J, Towle D, et al. Molecular Diagnosis of Shrimp Allergy: Efficiency of Several Allergens to Predict Clinical Reactivity. J Allergy Clin Immunol Pract [Internet]. 2015 Jul 1 [cited 2023 Jun 9];3(4):521-529.e10. Available from: https://www.sciencedirect.com/science/article/abs/pii/S2213219815000483 

9. Patel P, Komorowski AS, Mack DP. An allergist’s approach to food poisoning. Ann Allergy, Asthma Immunol [Internet]. 2023 Apr 1 [cited 2023 May 5];130(4):444–51. Available from: https://pubmed.ncbi.nlm.nih.gov/36334721/ 

10. Milaciu M V, Ciumărnean L, Orășan OH, Para I, Alexescu T, Negrean V. Semiology of food poisoning. Int J Bioflux Soc [Internet]. 2015 [cited 2023 May 10];8(2):108–13. Available from: http://hvm.bioflux.com.ro/docs/2015.108-113.pdf 

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