Is It Safe to Refreeze Thawed Meat and Fish? Nutritional Insights

Safety and Nutrition of Thawed and Refrozen Meat

I would like to ask the doctor, when buying frozen fish or meat strips, if I need to repackage them and they are too hard or stuck together, is it acceptable to thaw them in the refrigerator until I can cut or separate them, and then refreeze them? Does this count as thawing and refreezing? Is it unsafe to thaw and then refreeze? Will this process lead to an increase in bacteria, and will all the nutritional components be lost, such as fats, proteins, iron, and vitamin B1? Thank you.

Mike, 20~29 year old female. Ask Date: 2018/06/11

Dr. Cai Xiuwen reply Nutrition

Hello! The storage duration of fish varies between refrigeration and freezing.
It is generally recommended to refrigerate fish for about 2-3 days and to freeze it for about 2-3 weeks.
The storage period is influenced by factors such as the time of pre-processing, exposure to moisture and air, temperature, and packaging conditions.
When fish is thawed and then repackaged for refrigeration, the water molecules in the fish can form ice crystals.
Upon thawing again, the fish's ability to retain moisture decreases, and bacteria can proliferate during this process, thereby shortening the storage duration.
The nutrients, particularly the beneficial unsaturated fats in the fish, are also more susceptible to oxidation.
Therefore, for food safety, it is crucial to avoid repeated thawing and to consume the fish as soon as possible to prevent foodborne illness.
Wishing you safety and health.
This information is provided by Dietitian Tsai Hsiu-Wen from Nantou Hospital, Ministry of Health and Welfare.

Reply Date: 2018/06/11

More Info

Refreezing thawed meat and fish is a topic that raises concerns regarding both safety and nutritional quality. When you thaw meat or fish, it is important to understand the implications of refreezing, especially if the thawing process was not done properly.

To begin with, when you thaw meat or fish in the refrigerator, it is generally safe to refreeze it without cooking. This is because the food remains at a safe temperature (below 40°F or 4°C) during the thawing process, which minimizes the risk of bacterial growth. However, if you thaw meat or fish using other methods, such as in warm water or at room temperature, the risk of bacterial growth increases significantly. In such cases, it is not advisable to refreeze the product without cooking it first.

When you thaw meat or fish and then refreeze it, there are several factors to consider. First, the texture and quality of the meat or fish may be compromised. The process of freezing and thawing causes ice crystals to form within the cells of the meat or fish. When these ice crystals melt, they can cause the cells to rupture, leading to a loss of moisture and resulting in a drier texture upon cooking. This is particularly noticeable in fish, which is more delicate than meat.

Regarding nutritional content, while some nutrients may be lost during the freezing and thawing process, the extent of this loss is generally minimal. Nutrients such as protein, fat, iron, and B vitamins are relatively stable during freezing. However, the quality of unsaturated fats may be affected due to oxidation, especially if the food is not stored properly. For instance, if fish is exposed to air during thawing, it can lead to rancidity, which affects both flavor and nutritional quality.

It is also important to consider the potential for bacterial growth. When meat or fish is thawed, especially if done improperly, bacteria can multiply rapidly. If you refreeze food that has been thawed improperly, you risk increasing the bacterial load, which can lead to foodborne illnesses when consumed. Therefore, it is crucial to ensure that any thawed meat or fish is handled safely and cooked promptly if there are any doubts about its safety.

In summary, while it is safe to refreeze meat or fish that has been thawed in the refrigerator, it is essential to be cautious about how the thawing process is conducted. If thawed at room temperature or in warm water, it is best to cook the meat or fish before refreezing. Nutritional losses during the freezing and thawing process are generally minimal, but the quality and safety of the food should always be prioritized. To maintain the best quality, it is advisable to plan ahead and only thaw the amount of meat or fish that you intend to use, thereby minimizing the need for refreezing.

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