What is botulinum in food, the symptoms and how to avoid contamination – WWN

What is botulinum in food, the symptoms and how to avoid contamination – WWN

Of Cristina Marrone

Minimal quantities of foods with botulinum toxin can be enough to cause the disease botulism, which can be fatal. Tips for preparing preserves safely

A 46 year old woman Gerardina Corsano from Ariano Irpinio died due to suspected food poisoning caused by botulinum, perhaps present in a chili condiment used in the restaurant. Even the consumption of minimal quantities of food contaminated with botulinum toxins may be enough to cause the disease. botulismthat is, the blockage of the transmission of the nervous signal to the muscle, a condition that can be fatal

What is botulinum toxin

The toxin of botulism develops from the microorganism Clostridium botulinum, common in soil and air and harmless until in contact with oxygen. What turns it into a health threat are sometimes the cactive food storage conditions. There neuro
in fact it comes produced in the absence of oxygen and when temperatures exceed five to ten degrees. However, it does not form in very acidic environments, such as tomato sauce or vinegar. His true enemy the heat, which destroys it: just cook food at 105 degrees for two hours or in the pressure cooker for ten minutes. However, if cooking is done briefly and foods are stored in oil there is the risk that some spores may escape.

Generally the level of environmental contamination in botulinum spores is very low and can therefore be punctiform in the same production batch it may occur that only some packages are contaminated.


Symptoms of intoxication manifest themselves inusually within 12-24 hours
and usually the earlier they are, the more serious the disease. They can vary from a mild malaise that does not require medical intervention, up to a fulminant illness that leads to death in a few days. The first symptoms are characterized by weakness, dizziness, dry throat they are followed by the signs of paralysisespecially affecting muscles innervated by cranial nerves: difficulty swallowing and speaking, visual disturbances (strabismus, double vision, drooping of the eyelids) in severe cases, death occurs paralysis of the respiratory muscles. For botulinum poisoning, an antitoxin taken in the body is used first hours after the onset of symptoms. If the patient survives, recovery is rapid and complete.

How botulinum poisoning occurs

Clostridium botulinum is a bacterium capable of producing a neurotoxin which interferes at the level of nerve endings causing the blockage of some vital functions such as respiratory function. Poisoning with this bacterium usually occurs following the consumption of canned food (canned and preserved with a low degree of acidity, in oil or vacuum and not adequately sterilised). The presence of botulinum in food should be suspected in the presence of swelling of the liddue to the gas leakage upon opening and its unpleasant odor.

How to avoid botulism in preserves

A set of food safety rules they can be useful to those who prepare home preserves: from jams to pickles, from sauces to products in oil.
Mushrooms, olives, peppers, aubergines and green beans in oil are the foods at greatest risk and we must wash them well to prevent soil residue from being present in clean, dry and airtight jars.
Acidification above 4.6 pH makes the environment unsuitable for the growth of botulinum for this reason when preparing pickled preserves, the vinegar must completely cover the preserved productwithout skimping.
– it is necessary to wash vegetables, dishes, worktops and containers to limit or eliminate the presence of the bacteria and spores. For this purpose they would go the production phases are separated (for example, do not reuse used containers for vegetables to be cleaned and then put the washed vegetables back in).
– Containers should not be filled to the brim but an empty space should be left between the maximum liquid level and the neck of the container to be able to generate a vacuum inside the container.
Botulinum toxin is destroyed at high temperatures and therefore the sterilization of jarred and canned foods, through boiling for at least 10 minutes, guarantees their elimination. During heat treatment the jars must be completely immersed in boiling water. This is not a real sterilization (it would be necessary to reach 121 for 3-4 minutes to also eliminate the spores) but in this way the
to most microorganisms
– Botulinum toxins are all thermolabile and are therefore rapidly destroyed by common food cooking temperatures (at least 80C for 5 minutes). This is why it is recommended bring homemade preserves to the boil before using them (for example, when preparing a sauce, heating it adequately).
– Once the jar has been opened, the product should be stored in the refrigerator for a short time.
-Throw away stored products you have on doubts about the state of conservation, which have suffered breakages in the cold chain, or whose perfect preservation is not certain (for example the presence of air in vacuum-packed containers, hermetic capsules which emit the characteristic “click” following pressure on the cap or on the contrary, capsules “swollen” due to bacterial fermentation). The product inside must not have an unnatural color or odor, nor bubbles rising upwards from the bottom.

November 1, 2023 (changed November 1, 2023 | 5:30 pm)

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