What is botulinum


Clostridium botulinum is a notorious food pathogen. When it reproduces vigorously, it will produce an extremely poisonous and deadly toxin - botulinum toxin. If humans accidentally eat it, it will cause botulinum toxin poisoning. There are 7 types of botulinum toxin, each with different toxicity. Type A and type B are mainly poisonous to humans.

To ask how toxic botulinum toxin is, we must first start with arsenic. Arsenic is a highly toxic substance in people's minds, but it is far inferior to potassium cyanide, and potassium cyanide is far inferior to botulinum toxin. 1 microgram of botulinum toxin can kill a person. If calculated this way, 1 gram of botulinum toxin is enough to kill 1 million people. Because botulinum toxin is the king of poisons, it has been developed as a biochemical weapon by some countries.

The molecules of botulinum toxin can enter nerve cells, preventing neurons from releasing neurotransmitters, causing "communication" barriers between neurons, and information cannot be transmitted, resulting in a series of symptoms of muscle paralysis. Botulinum toxin poisoning, like other common food poisonings, will cause self-help reactions such as nausea and vomiting, as well as symptoms such as dizziness and muscle weakness. The more "unique" symptoms of botulinum toxin poisoning are drooping eyelids and double vision. Food poisoning caused by other bacteria or bacterial toxins does not have these symptoms. If the poisoning is severe, respiratory paralysis may occur and lead to death. If timely targeted antitoxin treatment is not obtained, the fatality rate of this disease exceeds that of H7N9 virus infection.

Clostridium botulinum in meat products

Since ancient times, countless people have fallen to this poison, especially Europeans. Europeans have long discovered that eating meat products is prone to botulinum toxin poisoning. The word Botulinum comes from the Latin word botulus for "meat sausage". Because hundreds of years ago, people did not know the real cause of poisoning, but they only vaguely knew that eating meat sausage had the risk of poisoning and death. Only after the gradual rise of microbiology did people confirm that this poisoning symptom was caused by botulinum toxin.

Clostridium botulinum is actually not a rare thing. It exists widely in nature, and this bacterium can be found in soil and feces. This bacterium is afraid of acid and heat, and has poor fecundity in places with good ventilation and sufficient oxygen. It especially likes protein-rich foods, such as sausages and ham. The ventilation conditions in the human intestine are not that good and the acidity is relatively low. Clostridium botulinum can also survive, but 37°C is not its optimal toxin-producing temperature.

But people may ask: Don’t sausages and canned meats go through high-temperature sterilization or even sterilization? Isn’t Clostridium botulinum afraid of heat? Thankfully, the bacteria itself is not heat-resistant, and neither is botulinum toxin. Although this toxin is very poisonous, it loses its toxicity after being boiled at 100°C for just one or two minutes. But the problem is that although many cooked meats are heated during production, they need to be stored for several days before being sold, and they are usually eaten as cold cuts without heating, so it is difficult to ensure safety. In order to avoid being harmed by botulinum toxin, ancient people have long explored a good method - adding nitrite, because it is particularly effective in inhibiting Clostridium botulinum.

Although nitrite is also toxic and will synthesize trace amounts of carcinogen nitrosamines in meat, its toxicity is simply "out of reach" compared with botulinum toxin. Therefore, using strictly limited amounts of nitrite to avoid the risk of botulinum toxin poisoning is absolutely a wise move for meat processing, so all countries in the world allow the addition of nitrite to processed meat products. As long as you carefully look at the labels of sausages, ham and other products, you will always see the words "sodium nitrite" in the ingredient list.

The author used to be very opposed to the use of nitrite in the catering industry. The reason is that catering products are produced and consumed at the time, and customers will not eat leftovers, so there is no need to use them. Moreover, if nitrite is not properly managed, it is easy to cause excessive levels or even poisoning accidents. But processed meat products cannot be eaten on the same day they are made, so they must be added. The only way to avoid the harmful effects of trace amounts of carcinogens is to eat less processed meat products sold outside and cook more fresh meat at home.

Clostridium botulinum in the kitchen

However, in home kitchens, this terrible toxin is often ignored. For example, soy products, cooked soybeans, and bean paste, such as leftover fish, leftover tofu, and leftover eggs at home, especially those homemade fermented soy products, may have Clostridium botulinum lurking, especially in It is very dangerous to eat without reheating after being stored at room temperature.

Because of this, people often say that leftovers should be thoroughly heated and sterilized. Boiling for a few minutes, or steaming over high heat in a basket for a few minutes can sterilize and disinfect. It is dangerous to eat leftovers and rice that have been turned at room temperature without heating them. Although some people may say, "I've eaten it many times and it's fine," but if something goes wrong once and I suffer from gastroenteritis or even botulinum toxin poisoning, it will be troublesome. The so-called food safety means being very safe, not taking frequent risks.

However, heating can only guarantee safety at the time, but cannot guarantee that food will remain safe after long-term storage. Although both Clostridium botulinum and botulinum toxin themselves are not heat-resistant. The characteristic of Bacillus is that it can form dormant bodies called "spores" within the cells. Once the bacteria turns into a spore state, it is very "skinned" and is not afraid of heating at 100°C. The spores need to be heated above 120°C for 20 to 30 minutes to kill the spores. Generally, boiling for a few minutes is useless. If the spores are not destroyed, they will lurk in the food. Once the environmental conditions are suitable, the spores will "break out" and turn into active botulinum bacteria, multiply vigorously, and even produce toxins.

Therefore, in food processing, there are two types of treatment methods: sterilization and sterilization. Sterilization only kills living bacteria, not spores. The so-called pasteurized milk uses a "pasteurization" process of around 85°C to kill bacteria. However, the spores cannot be killed, so it must be stored under refrigerated conditions. It will deteriorate quickly at room temperature. The so-called normal temperature milk has been "sterilized" at temperatures above 120°C to eliminate spores. After aseptic filling and sealing while hot, the milk can be safely stored in aseptic cartons for more than 6 months, or even more than 1 year.

The spores of Clostridium botulinum are more "tenacious" than ordinary spores and can only be killed by cooking at a high temperature of 121°C for more than 30 minutes. Therefore, when making canned meat, if the heating temperature is slightly worse or the time is shorter, and the core temperature of the product does not meet the requirements, spores of Clostridium botulinum may "survive", causing safety hazards.

Of course, spores cannot enter an active state under all conditions. What it likes best is room temperature, 15℃~30℃ is its most comfortable environment. In a refrigerator below 10°C, or in a hot environment above 55°C, it cannot reproduce or produce toxins. Therefore, putting leftover food in the refrigerator quickly is an important measure to prevent botulinum toxin poisoning in the family.

The temperature is too high in summer, and supermarkets may not be able to provide full cold chain transportation and storage. The temperature is also very high on the way home from grocery shopping, which creates the potential for multiple pathogenic bacteria to multiply and even produce toxins. Therefore, it is best not to eat bulk cooked meat products, soy products, etc. bought from supermarkets. They must be reheated and sterilized before eating. Botulinum toxin only needs to be heated at about 80°C for 10 minutes, or at 100°C for 1 to 2 minutes to be eliminated.

In short, food safety risks are everywhere. Chemical substances are certainly worrying, and "purely natural" pathogenic bacteria are also "brutal by nature" and have killed countless people. We must not take it lightly. In order to stay away from various safety hazards, the most critical measure is to not be afraid of trouble and strictly control every step from the land to the table.