Although for our parents’ generation, freezing fish as a matter of course was little more than heresy, for at least a decade it has become standard practice in most homes.
The reason, at first, was imposed by anisakis, a parasite that can be found in a wide variety of fish (wild and farmed, freshwater, such as salmon; or saltwater, such as hake) and cephalopods (cuttlefish, octopus). …). But this is not the only reason. «In many homes, fresh fish is frozen to prevent the spread of the disease.» increase the shelf life of this foodwhich is naturally very perishable,” says María Casadevall, food technologist, dietician-nutritionist and member of the Spanish Academy of Nutrition and Dietetics.
However, to ensure food safety and preserve the organoleptic qualities of the fish as much as possible, it must be frozen and defrosted properly.
The importance of freezing fish quickly: avoiding anisakis
Anisakis is a round, elongated, transparent worm that is difficult to see. Spanish Agency for Food Safety and Nutrition warns that its presence can cause digestive disorders (anisakiasis) and allergic reactions that can sometimes be serious.
These symptoms can be avoided, or at least mitigated, by freezing or cooking correctly (cooking at at least 60°C in the centre of the product for a minimum of one minute). «Both methods kill the parasite, making it no longer infectious. Allergenicity is not completely eliminated.although the effect is reduced once the parasite is dead,” warns Casadevall.
This strategy makes it highly recommended. Freeze fish that are going to be consumed raw in advancelike anchovies in vinegar.
Pre-freezing preparation: key steps for safe fish
According to the food technologist and dietician-nutritionist, safe freezing should follow these instructions:
- Maximum freshness. Always freeze food in the moment of greatest freshness“This applies in particular to fish.”
- Evisceration. Before freezing, you should “gut the fish thoroughly, check for larvae in the abdomen and muscles of the fish, where they are difficult to see. Once you have found them, remove them with kitchen paper, leaving the fish as clean as possible.”
- At least 5 days. Freeze for 5 days in a freezer at -20°C. “If the freezer is not of this type and we know that we are not going to consume it immediately, it is better to buy the fish frozen directly.”
Differences in freezing whole fish vs. pieces
Although at first it may seem that it is the same to freeze it whole or in pieces, this is not the case. The expert points out that «it is It is better to freeze the fish in individual portions.. This way, the cold is distributed more evenly throughout the fish. In addition, it will be easier to defrost using only the part that is needed.”
Where in the freezer should it be placed?
It is important to freeze it in the coldest part of the freezer, the one for fish and meat. “And do not fill the whole drawer, because there must be space for the cold air to circulate and freeze evenly.” In this way, you get a quick freezewhich will preserve food safety and provide better quality of food when defrosted.
“Rapid freezing prevents the formation of large ice crystals that break the tissue structure, damaging the fish. In this way, the ice crystals will be more numerous but smaller and will not cause any defect in the food,” says María Casadevall.
However, we must bear in mind that most domestic freezers, especially when the manufacturer’s recommendations are not followed, do not produce rapid freezing, which is essential to maintain sensory characteristics once defrosted. Industrial freezing methods, on the other hand, apply capable processes. to lower the temperature of food drastically and in a very short timeThis system causes more ice crystals to form, but they are very small and rounded, and do not damage the tissues of the food or do so as little as possible. Therefore, we must pay attention to proper freezing at home..
What type of container should fish be frozen in?
The expert recommends:
- Use plastic wrap, vacuum bags with a hermetic seal or airtight containers to protect them from direct cold and from dehydration or frostbite.
- Make sure that the The packaging contains the least amount of air possible. and that adjusts or adapts as much as possible to the size of the fish.
- Dry the fish with disposable paper and set the freezing datehe name of the food and the number of servings. Once frozen, “we should consume them within a maximum period of 2 months.” By noting the date, we will know how long the food has been in the freezer. The name allows us to identify it without having to open the package, since once frozen, the foods take on a similar appearance.
How to safely defrost
In order for the fish to retain all its nutrients and flavour, despite being subjected to the freezing process, the defrosting process must be carefully monitored. In this regard, these are the tips by Maria Casadevall:
- Always defrost inside the refrigerator (4°C). Freezing stops the growth of microorganisms, but does not kill them. If we defrost at room temperature we are encouraging the growth of microorganisms and possible alterations in the food.
- Place the food in a container that has a grid that allows water and exudate not to have contact with the fish.
Can it be frozen again once it is cooked?
Defrosted fish can be refrozen as long as it is cooked beforehand and put back into the freezer “as quickly as possible, within a maximum of 2 hours,” says the dietician-nutritionist. In this case, it is necessary to try to “lower the temperature of the cooked food as quickly as possible and freeze it.”
In this way, we ensure that the food is exposed to dangerous temperatures for the shortest possible time, which are between 4 and 65°C. In this temperature range, microorganisms reproduce more quickly, potentially spoiling the food and increasing the risk of food poisoning.
However, we should not rush to measure hot or lukewarm cooked food in the freezer. This would cause the temperature inside to rise suddenly and could pose a risk to other foods that we have already frozen.
Consequences of improper freezing and defrosting of fish
Improper freezing can cause burns and frost on the surface of the food. “These are dry areas on the edges of frozen fish that often occur because the packaging is not suitable and the ice or the walls of the chamber touch the fish directly.”
On the other hand, the food technologist warns that defrosting fish at room temperature poses a risk of food poisoning. This risk increases if we also leave the fish on a flat surface, such as a plate, since it will end up surrounded by liquid, a habitat especially favorable to microbial proliferation.
The post Safe freezing of fish and seafood: practical and effective tips was published first on Nutriendo.
