![Anisakis en el Pescado: Qué Es, Síntomas y Cómo Evitarlo [2026] - Bacalalo](http://bacalalo.com/cdn/shop/articles/anisakis-en-el-pescado-que-es-sintomas-y-como-evitarlo-2026-4301044.jpg?v=1772706843&width=480)
Summary: Anisakis is a parasite present in many species of wild fish that can cause allergic reactions and serious digestive problems. In this comprehensive guide, we explain exactly what it is, what symptoms it causes, which fish it is found in, how to eliminate it with freezing or cooking, and what Spanish legislation says. Additionally, we tell you why properly processed salted cod, canned goods, and smoked salmon are safe options.
What is anisakis
Anisakis (Anisakis simplex) is a nematode or parasitic worm that lives in the digestive tract of numerous species of marine fish and cephalopods. In its larval form, it measures between 2 and 3 centimeters in length, is whitish or slightly translucent in color, and is usually found coiled in a spiral shape in the abdominal cavity or in the musculature of the fish.
According to data from the Spanish Agency for Food Safety and Nutrition (AESAN), Spain is the second country in the world with the highest incidence of anisakiasis after Japan, mainly due to our tradition of consuming raw or undercooked fish: marinated anchovies (boquerones en vinagre), sushi, ceviches, cold escabeches, and marinated preparations.
The problem is not just the parasitic infection itself. Even dead anisakis larvae can trigger allergic reactions in sensitized individuals, ranging from a simple rash to anaphylactic shock. Therefore, knowing this parasite well and knowing how to prevent it is essential if you regularly consume fish.
Life cycle of the parasite
Understanding how anisakis gets to your plate will help you better understand prevention methods. Its biological cycle goes through several phases:
- Marine mammals (definitive host): Cetaceans such as dolphins and whales host adult anisakis in their stomachs. Eggs are expelled into the sea through feces.
- Seawater: The eggs hatch and the larvae float freely in the ocean.
- Small crustaceans (first intermediate host): Krill and other small crustaceans ingest the larvae.
- Fish and cephalopods (second intermediate host): By feeding on these crustaceans, fish such as hake, fresh cod, sardines, or anchovies acquire the larvae, which migrate from the digestive tract to the fish's musculature.
- Humans (accidental host): When we consume raw or insufficiently cooked parasitized fish, the larvae try to penetrate the gastric or intestinal mucosa, causing anisakiasis.
An important fact: anisakis only completes its life cycle in marine mammals. In humans, it cannot develop, but it does cause damage by trying to perforate the stomach or intestinal wall.
Symptoms of anisakiasis
Symptoms of anisakis infection usually appear between 1 and 12 hours after ingesting contaminated fish, although in some cases they may take several days. Anisakiasis manifests in two main forms:
Gastrointestinal anisakiasis
- Intense abdominal pain, often in the stomach area (epigastrium)
- Nausea and vomiting
- Diarrhea or constipation
- Abdominal distension
- In severe cases, it can mimic appendicitis, a perforated ulcer, or even intestinal obstruction
Allergic anisakiasis
- Urticaria (hives on the skin with intense itching)
- Angioedema (swelling of the lips, eyelids, hands, or feet)
- Respiratory difficulty (glottis edema, bronchospasm)
- Anaphylactic shock in the most severe cases
People allergic to anisakis can react even to well-cooked fish if the allergenic proteins of the parasite remain in the fish tissue. These proteins are heat-resistant: they resist both freezing and cooking. If you suspect you may have an allergy to anisakis, consult an allergist for appropriate tests (prick test, specific IgE).
Which fish have anisakis
Not all fish present the same risk. The prevalence of anisakis varies enormously depending on the species, the catch area, and whether the fish has been eviscerated (gutted) immediately after fishing. The species with the highest incidence are:
- Hake: Up to 80-100% of specimens from the Cantabrian Sea and Atlantic contain anisakis larvae.
- Anchovy/fresh anchovy: Very high prevalence, especially concerning because it is consumed in vinegar (raw).
- Fresh cod: High percentage of parasitization in North Atlantic specimens.
- Sardine: Moderate-high prevalence, variable depending on the catch area.
- Wild salmon: Very common in wild-caught specimens.
- Horse mackerel: High incidence, similar to hake.
- Mackerel: High prevalence, especially in the Atlantic.
- Monkfish: Moderate prevalence.
- Bonito and tuna: Low prevalence in the musculature, although it can be found in viscera.
- Cephalopods: Squid and cuttlefish can contain larvae, though less frequently.
The general rule is: any wild marine fish or cephalopod may contain anisakis. If you consume any of these species, always apply the preventive measures explained later.
Which fish do NOT have anisakis
There are several groups of seafood products that are anisakis-free or whose risk is practically zero:
- Bivalve mollusks: Mussels, clams, oysters, cockles, razor shells, and scallops. Due to their filtration feeding system, they do not ingest anisakis larvae.
- Freshwater fish: River trout, carp, pike. Anisakis is an exclusively marine parasite (note: salmon, although it ascends rivers, feeds in the sea).
- Aquaculture fish: Gilthead bream, sea bass, turbot, trout, and farmed salmon. Controlled feeding with feed prevents infection. According to the EFSA (European Food Safety Authority), the risk of anisakis in aquaculture is practically non-existent if the fish has been raised with controlled feeding.
- Crustaceans: Lobster, common lobster, shrimp, prawn, langoustine, spider crab, and velvet crab. They are not intermediate hosts of the L3 larva that affects humans.
- Semi-preserved and canned products: Products that have undergone industrial heat treatment (autoclave sterilization) are free of viable larvae.
How to kill anisakis
There are two reliable and scientifically proven methods to eliminate anisakis larvae from fish. Both are based on extreme temperatures maintained for a sufficient time:
Freezing
It is the safest method for raw or undercooked preparations. European regulations (EC Regulation 853/2004) and Spanish legislation (RD 1420/2006) establish:
- -20 C for at least 24 hours: This is the legal standard in Spain for restaurants and establishments that serve raw fish or in preparations where sufficient cooking temperature is not reached.
- -35 C for at least 15 hours: Faster industrial method.
- -20 C for 7 days: AESAN recommendation for domestic freezers (three-star or higher), as they may not reach -20 C uniformly in the center of the piece.
Attention: Freezers with less than three stars (marked with one or two snowflakes) do not guarantee reaching -20 C. If your freezer is of this type, AESAN recommends buying industrially frozen fish.
Cooking
Heat also destroys anisakis larvae, provided that a sufficient temperature is reached in the center of the product:
- 60 C in the center of the piece for at least 1 minute: This is what the legislation establishes. In practice, cooking at 70 C or more for 2 minutes guarantees total destruction.
- Grilled, baked, fried, or boiled preparations that reach this temperature are safe.
- Microwaving can leave uneven cold spots, so ensure homogeneous cooking.
Table: freezing vs cooking
| Method | Temperature | Minimum time | Suitable for |
|---|---|---|---|
| Domestic freezing | -20 C (three stars) | 7 days | Sushi, ceviche, marinated anchovies, marinated dishes |
| Industrial freezing | -20 C (guaranteed) | 24 hours | Restaurants, fishmongers, industrial processing |
| Ultra-freezing | -35 C | 15 hours | Large-scale food industry |
| Cooking (oven, grill, boiled) | +60 C in the center of the piece | 1-2 minutes | Any cooked preparation |
| Intense salting | Very high saline concentration (>9% NaCl) | Weeks of curing | Dried salted cod, mojama |
| Sterilization (canned goods) | +115 C (autoclave) | According to can size | Canned goods, glass jar semi-preserved goods |
Spanish law on anisakis
Spain has one of the strictest regulations in the world regarding anisakis, precisely because we are one of the most affected countries. The reference legislation is Royal Decree 1420/2006, of December 1, which establishes measures to prevent anisakiasis in fishery products. Its key points are:
- Restaurants, bars, and collective dining rooms: They are obliged to freeze all fish that they are going to serve raw or with insufficient treatment to kill the parasite (vinegar, escabeche, marinade, cold smoking, light salting). Freezing must be carried out at -20 C or lower for at least 24 hours.
- Consumer information: Establishments must inform that the fish has been previously frozen, and they must have a record of the freezing processes.
- Fishmongers: They must place visible signs informing consumers about the need to freeze fish if it is to be consumed raw or undercooked.
- Exemptions: Bivalve mollusks, aquaculture fish fed with feed, and products that have been industrially frozen for a sufficient time and temperature are exempt.
AESAN (Spanish Agency for Food Safety and Nutrition) complements this regulation with periodic recommendations for the end consumer, insisting on domestic freezing for at least 5 days as an additional safety measure against possible inaccuracies of domestic thermometers.
Does salted cod have anisakis?
This is one of the most frequent questions from our customers, and the answer is reassuring: traditional dried salted cod does not present a risk of live anisakis.
The curing process of dried salted cod involves several stages that make the parasite's survival unfeasible:
- Immediate evisceration: Cod is gutted right after capture, removing the highest concentration of larvae (which are mainly lodged in the abdominal cavity).
- Intense salting: Salt is applied in concentrations much higher than 9% NaCl (usually between 18% and 25%). This saline concentration causes dehydration and death of anisakis larvae due to osmotic pressure.
- Prolonged drying: Cod is dried for weeks or months under controlled conditions. The drastic reduction of the product's water activity (aw) prevents the survival of any parasitic form.
- Desalting and cooking: Before consumption, dried cod is desalted in water for 24-48 hours and then cooked at temperatures well above 60 C.
Scientific studies published in journals such as Food Control and International Journal of Food Microbiology confirm that the combination of intense salting (>6% NaCl) and prolonged dehydration is lethal to L3 larvae of Anisakis simplex. The dried salted cod we sell at Bacalalo comes from Iceland, where it is processed with the highest industry standards, guaranteeing a completely safe product.
You can enjoy our cod and all its nutritional properties with complete peace of mind, from a pil pil cod loin to a cod with chickpeas in the traditional style.
100% safe cod products
Does smoked salmon have anisakis?
It depends on the type of smoking and prior processing. We must distinguish between two very different processes:
Hot smoking
Salmon is smoked at temperatures exceeding 60-80 C for several hours. This heat treatment is sufficient to destroy any anisakis larvae. The resulting product is completely safe.
Cold smoking
Salmon is smoked at temperatures below 30 C, which is not enough to eliminate the parasite. However, the industry applies mandatory prior freezing (at -20 C for a minimum of 24 hours) before the smoking process. In addition, the vast majority of commercial smoked salmon in Europe comes from aquaculture (Norway, Scotland), where the risk of anisakis is practically zero due to controlled feeding with feed.
The smoked salmon you will find at Bacalalo complies with all European food safety requirements. Our suppliers, such as Ahumados Domínguez, use Norwegian farmed salmon and apply the prior freezing protocols required by law. You can enjoy it with complete confidence in preparations such as our gravlax-style marinated salmon or on toast.
Safe and delicious smoked salmon
Prevention at home: 7 basic rules
Following these recommendations based on AESAN guidelines and European regulations will allow you to consume fish without risk:
- Always freeze fish that you are going to eat raw or undercooked. Marinated anchovies (boquerones en vinagre), sashimi, ceviche, tataki, carpaccio, or any preparation where the center of the fish does not exceed 60 C. Freeze for at least 5 days in a three-star or higher domestic freezer.
- Buy eviscerated fish. Always ask for the fish to be cleaned at the fishmonger, removing the viscera as soon as possible. Larvae migrate from the viscera to the musculature after the fish's death.
- Cook thoroughly. Baked, grilled, fried, or boiled, make sure the thickest part of the fish reaches at least 60 C. A good indicator is that the meat separates easily and is opaque to the center.
- Visually inspect the fish. When cleaning large pieces, inspect the abdominal cavity and musculature. Anisakis larvae are visible to the naked eye (2-3 cm, whitish, coiled in a spiral).
- Check your freezer. Make sure your freezer has at least three stars (***) and reaches -20 C. If it only has one or two stars, buy industrially frozen fish.
- Don't rely solely on vinegar, lemon, or light salt. Acid marinades (vinegar, citrus) do not kill anisakis larvae. Neither does salt in low concentration nor cold smoking alone.
- When in doubt, cook. If you are not sure if you have frozen correctly or for long enough, cook the fish thoroughly. It is the simplest and most effective measure.
If you like to prepare tuna tataki or other recipes where the fish remains raw in the center, prior freezing is absolutely essential.
Table: risk level by type of preparation
| Preparation | Anisakis risk | Requires prior freezing? |
|---|---|---|
| Sushi / sashimi | HIGH | Yes, mandatory |
| Ceviche / lemon marinated | HIGH | Yes, mandatory |
| Marinated anchovies (boquerones en vinagre) | HIGH | Yes, mandatory |
| Tataki (seared outside, raw inside) | HIGH | Yes, mandatory |
| Escabeche without prior cooking | MEDIUM-HIGH | Yes, mandatory |
| Cold smoking | MEDIUM | Yes (industry does it) |
| Grill / oven / frying (well-done) | LOW | No, if cooked thoroughly |
| Dried salted cod (cured) | VERY LOW | No |
| Canned goods (sterilized) | NONE | No |
| Bivalve mollusks (mussels, clams) | NONE | No |
Anisakis in canned goods
Canned goods in cans or glass jars are one of the safest options against anisakis. The reason is simple: the industrial sterilization process in an autoclave subjects the product to temperatures above 115 C for a prolonged period, which completely destroys any form of parasitic life, including anisakis larvae and their allergenic proteins.
This applies to all types of canned goods:
- Anchovies in olive oil
- Canned sardines
- Canned tuna and bonito
- Marinated mussels
- Natural clams
- Cockles
- Bonito belly (ventresca)
The gourmet canned goods we offer at Bacalalo go through this rigorous industrial process. Brands such as Dardo, Olasagasti, Baymar, and Leonardo apply the most demanding standards of the Spanish and Galician canning industry. If you are looking for the safest and most convenient option to enjoy fish, canned goods are an infallible bet. Discover more in our guide to Spanish gourmet canned goods.
Safe and delicious canned goods
Myths and truths about anisakis
There is a lot of misinformation about anisakis. Let's debunk the most common myths with scientific data:
MYTH: "Vinegar kills anisakis"
FALSE. The acetic acid in vinegar does not destroy anisakis larvae. Marinated anchovies (boquerones en vinagre) are precisely one of the main causes of anisakiasis in Spain. It is essential to pre-freeze the fish before preparing this traditional tapa.
MYTH: "Lemon and salt eliminate the parasite"
FALSE. Neither lemon juice nor salt in low concentration (such as that used in ceviches) destroy the larvae. Salt is only effective in very high concentrations (>9% NaCl) maintained for weeks, as in traditional cod salting.
MYTH: "If the fish is fresh it doesn't have anisakis"
FALSE. The freshness of the fish has no relation to the presence of anisakis. The parasite infects live fish in the sea. In fact, the fresher the fish, the more active the larvae will be.
MYTH: "Anisakis is only found in cheap fish"
FALSE. Anisakis does not distinguish by price. Expensive species such as Cantabrian hake or wild salmon show very high rates of parasitization.
TRUTH: "Aquaculture fish is safe"
TRUE. EFSA confirms that fish raised with controlled feeding in fish farms have a negligible risk of containing anisakis, provided they have not been fed with raw wild fish.
TRUTH: "Spain is one of the countries with the most cases"
TRUE. Our gastronomic tradition of consuming raw or marinated fish (marinated anchovies, marinated salmon, escabeches) places Spain as the second country in the world in incidence, behind Japan.
Frequently asked questions about anisakis
Can anisakis be seen with the naked eye?
Yes. Anisakis L3 larvae measure between 2 and 3 centimeters, are whitish in color and are usually found coiled in a spiral. They are perfectly visible if you inspect the abdominal cavity and fish fillets with good lighting.
How long do you have to freeze fish to kill anisakis?
In a three-star or higher domestic freezer (-20 C), at least 5 days according to AESAN (7 days as an additional safety margin). In industrially guaranteed freezing at -20 C, 24 hours are sufficient. At -35 C, 15 hours are enough.
At what cooking temperature does anisakis die?
Larvae die when the center of the piece reaches 60 C for at least 1 minute. For safety, it is recommended to cook at 70 C or more for 2 minutes. In practice, when the fish is well done (meat opaque and separates easily), the anisakis has been destroyed.
Can anisakis cause allergies even with cooked fish?
Yes. People allergic to anisakis (sensitized to its proteins) can react even to well-cooked or frozen fish, because certain allergenic proteins of the parasite resist heat and cold. In these cases, an allergist can determine the level of sensitization and recommend whether it is necessary to avoid certain species.
Do shrimp, prawns, and other shellfish have anisakis?
No. Crustaceans (shrimp, prawns, langoustines, lobsters, spider crabs, velvet crabs) are not hosts of the anisakis L3 larva that affects humans. Bivalve mollusks (mussels, clams, oysters, cockles, razor shells) also do not present a risk, as they feed by filtration.
Is there anisakis in farmed salmon?
The risk is practically non-existent. Farmed salmon (Norway, Scotland, Chile) is fed with controlled feed that does not contain anisakis larvae. EFSA has confirmed this in multiple reports. This is one of the reasons why commercial smoked salmon is considered safe.
Can salted cod have live anisakis?
No. The intensive salting process (>18% salt) combined with prolonged drying for weeks completely eliminates any viable larvae. In addition, dried salted cod is always cooked before consumption, adding an additional safety barrier.
What do I do if I think I've eaten fish with anisakis?
If you experience intense abdominal pain, nausea, vomiting, or an allergic reaction (hives, swelling, difficulty breathing) between 1 and 12 hours after eating raw or undercooked fish, go to the emergency room. Inform the doctor that you have consumed fish. Diagnosis is usually made by endoscopy (where larvae can be removed) or serological tests.
Is it mandatory to freeze fish in restaurants?
Yes, in Spain, it is established by Royal Decree 1420/2006. All restaurants and collective catering establishments are obliged to freeze at -20 C for at least 24 hours all fish that they are going to serve raw, marinated, in escabeche, cold smoked, or with any treatment that does not guarantee the death of the parasite.
Do canned anchovies have anisakis?
No. Canned anchovies (in cans or glass jars) have undergone a sterilization process at more than 115 C that eliminates any parasitic forms. Semi-preserved anchovies in oil (those that are refrigerated) are also safe, as they go through a long curing process in salt that eliminates larvae before filleting.
Can I eat sushi during pregnancy because of anisakis?
Spanish health authorities recommend that pregnant women avoid consuming raw or undercooked fish not only because of the risk of anisakis, but also because of other pathogens (Listeria, Toxoplasma). If you want to eat sushi during pregnancy, opt for varieties with well-cooked fish or vegetables, and confirm that the restaurant complies with the mandatory prior freezing.
Can the microwave kill anisakis?
Technically yes, if the center of the piece reaches 60 C for at least 1 minute. However, the microwave heats unevenly and can leave cold spots inside the fish where the larvae survive. Therefore, it is not the most recommended method. If you use it, make sure the cooking is homogeneous, stirring and letting the fish rest to equalize the temperature.
