Are Scallops a High Risk Food? Understanding the Dangers and Safe Practices

November 25, 2025 •

4 min read

According to the Centers for Disease Control and Prevention (CDC), shellfish can be a source of toxins that cause foodborne illness, prompting many to ask: are scallops a high risk food? While they are generally safe and nutritious, scallops are filter-feeders that can accumulate contaminants like heavy metals and bacteria from their environment. The level of risk largely depends on proper sourcing, handling, and cooking methods.

Quick Summary

Scallops, like other shellfish, carry potential risks from environmental contaminants and bacteria, but these risks are manageable with safe handling. The primary concerns involve marine biotoxins, heavy metal accumulation, and bacterial pathogens. Ensuring proper sourcing and thorough cooking are the most effective preventive measures.

Key Points

Sourcing is Key: Always buy scallops from a reputable vendor or approved establishment to ensure they were harvested from monitored waters and handled properly.
The Viscera is a Hazard: Marine biotoxins and contaminants accumulate in the viscera (guts) of scallops. For maximum safety, remove and discard this part before cooking, especially if not eating the adductor muscle exclusively.
Don't Eat Them Raw Unless Certified: Eating raw scallops carries a high risk of bacterial illness, such as Vibrio infection. Only consume raw scallops if they are specifically labeled 'sushi-grade' from a trusted source.
Cook to 145°F: The most effective way to kill pathogens is to cook scallops thoroughly until they are opaque and reach an internal temperature of 145°F (63°C).
Freshness Indicators: Fresh scallops have a mild, sweet smell and firm, translucent flesh. A strong, fishy, or ammonia-like odor is a sign of spoilage, and they should be discarded.
Manage Heavy Metal Exposure: While low in mercury, scallops can accumulate other heavy metals. Consume them in moderation as part of a varied diet to minimize long-term exposure risks.
Be Aware of Allergies: Scallops are a common shellfish allergen. If you have a shellfish allergy, avoid them to prevent potentially severe reactions.

Demystifying the Risks: A Deeper Look at Scallop Safety

Scallops are a popular seafood choice, prized for their delicate texture and sweet flavor. However, like any shellfish, they come with potential risks that consumers should understand. These risks, while real, are often mitigated by stringent safety regulations and proper preparation techniques.

Marine Biotoxins and Shellfish Poisoning

One of the most significant concerns with scallops is the potential for marine biotoxin accumulation. Scallops are bivalve mollusks that feed by filtering large volumes of water, concentrating toxins produced by microscopic algae (dinoflagellates and diatoms). The most common types of shellfish poisoning include:

Paralytic Shellfish Poisoning (PSP): Caused by saxitoxin, this can result in neurological symptoms like tingling and numbness, and in severe cases, respiratory paralysis. While cooking doesn't destroy the toxin, removing the scallop's viscera (the internal organs) significantly reduces the risk.
Diarrhetic Shellfish Poisoning (DSP): This milder illness causes gastrointestinal distress, such as nausea, vomiting, and diarrhea. Like PSP, the toxins accumulate primarily in the digestive gland, which can be removed to minimize risk.
Amnesic Shellfish Poisoning (ASP): Caused by domoic acid, this can lead to memory loss and other neurological issues in severe cases, though it is relatively rare.

Heavy Metals and Contaminants

Beyond natural toxins, scallops can absorb heavy metals and other pollutants from their aquatic environment. While mercury levels are generally low in scallops compared to larger predatory fish, contaminants like cadmium, lead, and arsenic can still accumulate. The risk varies depending on the scallop's habitat, but regulatory bodies monitor harvesting waters to ensure levels remain within safe limits. For commercially sold scallops in the U.S., these levels are carefully controlled.

Bacterial Contamination and Spoilage

Bacterial issues are typically tied to poor handling and improper storage. Common foodborne pathogens like Vibrio can contaminate scallops, especially if they are harvested from polluted waters or mishandled after being caught. Symptoms often include watery diarrhea and other gastrointestinal problems. Thorough cooking is the most effective way to eliminate these bacteria.

Shellfish Allergies

Shellfish allergies are another primary risk factor, affecting a significant portion of the population. Scallops, being a mollusk, can trigger allergic reactions in sensitive individuals. Symptoms can range from mild (hives, indigestion) to severe (anaphylaxis). For those with a known shellfish allergy, avoiding scallops and other mollusks is essential.

How to Reduce Risk When Eating Scallops

Consumers can take several steps to minimize the risks associated with scallops and ensure a safe, enjoyable meal.

Sourcing and Purchasing Scallops

Buy from Reputable Sources: Purchase scallops from trusted retailers or fishmongers who adhere to strict food safety standards and can provide information about the sourcing and handling of their products.
Inspect for Freshness: Fresh scallops should have a mild, slightly sweet smell, not a strong or fishy odor. The flesh should be firm, translucent, and creamy-colored, not slimy or discolored.
Check for Certification: Look for scallops with proper identification marks, indicating they were harvested and processed in approved establishments.

Handling and Preparation

Keep Them Cold: Scallops must be stored properly in the refrigerator at temperatures below 40°F (4°C). Use fresh scallops within one to two days of purchase.
Separate and Clean: Prevent cross-contamination by keeping raw scallops separate from other foods. Wash shucked scallops in clean, running water, and pat them dry thoroughly before cooking.
Remove Viscera: For added safety, especially when there's concern about algal blooms, remove the viscera and gonad (roe) before cooking, as these parts accumulate the most toxins.

The Importance of Cooking Thoroughly

Cooking scallops to an internal temperature of 145°F (63°C) is crucial for killing harmful bacteria and viruses. While some prefer to eat scallops raw or undercooked, this carries an elevated risk of foodborne illness. Cooked scallops should be opaque and white in color. Overcooking can make them rubbery, so check for doneness carefully.

Scallops vs. Other Shellfish: A Comparison of Risks


Risk Factor	Scallops	Oysters	Clams/Mussels
Marine Biotoxins	Can accumulate toxins, primarily in viscera. Risk reduced by discarding viscera and proper sourcing.	High risk due to consumption of the whole animal. Often eaten raw, increasing exposure.	High risk, similar to oysters, as the whole body is consumed. Raw consumption is especially risky.
Heavy Metals	Tend to be lower in mercury than predatory fish. Can accumulate cadmium, but concentrations are monitored.	Can accumulate heavy metals depending on harvesting waters.	Similar to oysters, accumulation varies based on environment and regulations.
Bacterial Contamination	Risk primarily from improper handling or contaminated waters. Cooking eliminates risk.	High risk if eaten raw due to filtering large volumes of water. Source must be highly regulated.	Similar high risk to oysters if eaten raw or from contaminated areas. Thorough cooking is essential.
Allergies	Significant allergen risk for sensitive individuals.	Significant allergen risk. Often causes reactions in those allergic to other shellfish.	Significant allergen risk. Part of the mollusk group that can trigger allergies.
Safety Measures	Discard viscera, cook thoroughly. Buy from reputable sources.	Only eat raw from approved, regulated beds. Cook thoroughly otherwise.	Adhere to harvest regulations and ensure thorough cooking.

Conclusion

So, are scallops a high risk food? For most healthy adults who practice safe sourcing and handling, the risks are low. The key is in understanding the potential dangers, such as marine biotoxins and bacteria, and taking the necessary precautions. By purchasing scallops from reputable suppliers, ensuring they are fresh, and cooking them thoroughly, you can minimize risks and safely enjoy this nutritious seafood. Individuals with shellfish allergies, compromised immune systems, and pregnant women should exercise extra caution and, in some cases, avoid raw scallops altogether. The decision to eat scallops, especially raw, should be an informed one based on an understanding of these risks and preventive measures.

Frequently Asked Questions

The primary risks are foodborne illness from bacteria like Vibrio, contamination from marine biotoxins during algal blooms (which can cause various types of shellfish poisoning), and potential accumulation of heavy metals.

Yes, but the risk is significantly lower. Thorough cooking to an internal temperature of 145°F (63°C) kills bacteria. However, cooking does not eliminate heat-stable toxins from algal blooms, so proper sourcing is still critical.

A bad scallop has a strong, fishy, or ammonia-like smell. Fresh scallops should have a mild, slightly sweet, ocean-like aroma. If you notice a pungent smell, it is a sign of spoilage.

Eating raw scallops carries an elevated risk of foodborne illness from pathogens like Vibrio. Only consume them raw if they are 'sushi-grade' and sourced from highly reputable suppliers with strict safety controls.

No, scallops are generally low in mercury compared to larger, predatory fish. The FDA and EPA consider them a "good choice" for seafood consumption.

Store fresh scallops in the coldest part of your refrigerator at 40°F or below, ideally on ice. Keep them in an airtight container to prevent absorbing other odors and use them within one to two days.

The side muscle is a small, tough, crescent-shaped piece of tissue sometimes attached to the scallop. It is edible but can be chewy. It's best to pull it off before cooking for a more tender result.