Botulism in fish
Fish products are a source of highly digestible natural protein, phosphorus, calcium, and essential omega-3 fatty acids. During the period of intense mental activity, it is this product that is preferred by many students. About its positive effect on the human body can talk for hours. All good fish, provided that its meat is not contagious.
Only one small piece of fish affected by botulism (Clostridium botulinum) and well-being can be forgotten for a long time. What products are most dangerous? What is the guide when choosing fish products?
How a fish becomes contagious botulism
In Russia, botulism was described in the 19th century under the name “ichthyism” and linked the disease with the use of fish dishes. But botulism in fish, as well as in meat of herbivores, appears when they consume contaminated water or food. Often the source of the infection is the dead animal, since the cadaveric material is an ideal breeding ground for the causative agent of botulism.
After entering into the water clostridia are more often found in mud, from where they enter the body of fish. That is, herbivorous fish is often a source of infection. Carnivores are resistant to this microorganism and only in exceptional cases are subject to infection.
What types of fish are most often clostridia
Not only aquatic vertebrates themselves are the source of the hardest infection. Botulism in marine fish may meet with the same probability as in river and lake fish, if it has been infected from the outside after it has been caught. In this case, the source of infection can be:
- lack of proper cooking technology;
- if it is bad to wash the fish or cook it with dirty hands;
- In rare cases, contact with clostridia infected animals is possible.
So, many cases of infection with botulism in canned fish are known. In this case, the source of infection was only one bank. It is, as a rule, fish of home canning, cooked with spices in its own juice.
Despite the different sources of infection, scientists have identified some species of fish that are most often infected with the infection. These include:
- silver carp;
However, other species are also subject to infection. Thus, there is a case of botulism after eating whale meat in Alaska.
It happens, the infection is not some kind of fish, and improperly cooked, often at home. The source of infection with botulism is dried products purchased not in the store, but in the market. In the conditions of industrial production, the meat of aquatic vertebrates undergoes rigorous testing and serious selection. At home, these conditions cannot be fully observed.
How to distinguish infected fish botulism
Any sick animal is easy to distinguish from healthy. Herbivorous mammals become lethargic, their gait is disturbed, their movements change. But not in the case of fish - it is impossible to keep track of it, no one will watch the behavior of these animals in the river or the sea, so you will often have to be guided by the general principles of choosing the right product (usually already killed).
Botulism is also found in smoked products, so try to buy it not in the market from questionable sellers, but in specialized stores, better tested. If there is an unusual smell of smoked product - do not buy.
Reproduction of clostridia in the animal begins at a temperature of 25-35 ° C. If the fish were kept in this temperature range for at least some time, it is better not to take it.
Fresh contaminated product, as with any infection, immediately begins to smell unpleasant.
Characteristic signs of botulism in fish - it is covered with mucus, her eyes grow turbid.
How to avoid botulism in fish
To avoid possible contamination, it is necessary to choose the right fish and precisely follow the conditions for preparing dishes from it.
- Dirty fish is more likely to be infected with clostridia, make sure that the product being purchased is clean, wash it thoroughly before cooking, and clean it of its internal organs.
- Spore forms of clostridia can withstand temperatures of 6 ° C, so when choosing, try to give preference to frozen products. Or freeze it in the freezer for a few days after purchase.
- Another way to avoid botulism in fish - if you buy a ready-made dish, try to take it with a minimum amount of spices, - for the abundance of fragrant herbs you can hide the initially spoiled products.
- Vegetative forms of clostridia die at 60 ° C, and the spores can withstand 100 ° C for up to 30 minutes. Try to cook a long time fish at high temperatures.
For homemade fish should be fresh, well washed. If it is salted - the minimum salt content is 18%, with a smaller amount of harmful microorganisms do not die.
- Canned only after full processing. If, after opening, there is mold or an unpleasant smell in the bank - do not risk your health, throw it away.
No one will give a 100% answer about the type of fish with which the occurrence of botulism is predominantly associated. Marine and freshwater are equally susceptible to infection with this infection by eating foods containing clostridia. But in order to protect yourself and your loved ones from botulism infection, you need to pay attention to what you buy and observe the above preparation conditions.