Why food spoils and why food goes bad

Popular science: Why does food spoil?

The main cause of food spoilage is microorganisms. Microorganisms are everywhere in the environment, and food is easily contaminated by microorganisms during production, processing, transportation, storage and sales. As long as the temperature is right, microorganisms will grow and multiply, breaking down nutrients in food to meet their own needs.

At this time, the protein in the food is broken down into substances with very small molecular amounts, and finally broken down into peptides and organic acids. At this time, the substance will have an ammonia odor and sour taste, and the food will lose its original toughness and elasticity, and the color will be abnormal.

The second reason for food spoilage is the action of enzymes. There are many enzymes in animal food, and under the action of enzymes, the nutrients of the food are divided into a variety of low-level products. The daily occurrence of rancid rice and rotten fruits is the fermentation of carbohydrates caused by the decomposition of enzymes.

The third reason for food deterioration is the chemical reaction of food, there are unsaturated bonds in the molecular formula of fats, which are very unstable and easy to be oxidized, resulting in a series of chemical reactions.

The older the wine, the better, right? That's not entirely true. There are certain conditions that must be met for the wine to age, so that the ethyl acetate can be increased.

If the wine jar is not sealed or the sealing condition is not good, the temperature and humidity conditions are not appropriate, and after a long time, not only the alcohol will run away, but also become sour and rancid, and the acid will become vinegar. This is because there are acetic acid bacteria in the air, and when the wine comes into contact with the air, the acetic acid bacteria take the opportunity to enter the wine, and under the action of the acetic acid bacteria, the alcohol undergoes a chemical change and turns into acetic acid. In particular, beer and fruit wine are more likely to be rancid into vinegar.

Shochu such as Moutai, Xifeng, Fenjiu, etc. are different. Because the alcohol content in shochu is about 50, this concentration of alcohol has a bactericidal effect, and acetic acid bacteria cannot survive and multiply in shochu, so the alcohol does not turn into acetic acid.

Why food with salt doesn't spoil.

To put it simply, after the food is salted, the concentration of the salt solution will be very high, and all kinds of harmful microorganisms will lose water and die in it, so as to achieve the purpose of preservation.

Food spoilage is mainly caused by bacteria, and there are many bacteria that cause food spoilage, such as Salmonella has always been in the first place in our country, which mainly contaminates eggs and meat. Staphylococcus aureus contaminates meat and milk. Vibrio parahaemolyticus contaminates seafood and shellfish.

Bacillus cereus contaminates leftover rice. 1. Microorganisms play a role. Microorganisms are everywhere in the environment, and food is easily contaminated by microorganisms during production, processing, transportation, storage, and marketing.

As long as the temperature is right, microorganisms will grow and multiply and break down nutrients in food to meet their own needs. At this time, the protein in the food is destroyed, and the food will emit a foul and sour taste, lose its original toughness and elasticity, and the color will also change.

2. The role of enzymes. There are many enzymes in animal food, and under the action of enzymes, the nutrients of the food are broken down into a variety of lower products. The rice and fruit rot that we usually see are because the carbohydrates are broken down by enzymes and fermented.

3. Chemical reactions of food. Fats are easily oxidized, resulting in a series of chemical reactions, and the oxidized fats have a strange smell, such as fat meat will turn from white to yellow.

Spoiled food not only changes its appearance, loses its original color, aroma and taste quality, but also reduces its nutritional value, and also contains corresponding toxins that endanger human health.

<> spoiled food usually produces a large number of germs that are very harmful to the human body, such as peanuts and soybean foods, and a large amount of aflatoxin will be produced after spoilage, which is extremely carcinogenic. Spoiled fresh, fish and shrimp will produce a large number of toxic substances such as amine sleepiness, ammonia, hydrogen sulfide, etc., which will cause the human body to have poisoning symptoms such as chest tightness, vomiting, and conjunctival hyperemia.

Food at room temperature, if stored for a long time, deterioration will occur, and food has a shelf life, especially some foods bought, if the time exceeds the shelf life, do not eat again. Eating spoiled food is not good for health, mild causes diarrhea, severe may lead to food poisoning!

1. The 4 flavors of spoiled food

Hara. Foods containing more oil are left for a long time, such as oil, cakes, dry pickled products of fish and meat, walnuts, peanuts, melon seeds, etc., which will produce a bitter and numb, pungent and unpleasant taste, which is commonly known as "hala taste" by the common people. This is because fats and fats are easily oxidized and rancid, which leads to the development of hala flavor.

Rancid smell. Spoilage of protein-rich foods such as fish, pork, eggs, tofu, and dried tofu can produce a rancid odor. Under the action of microorganisms and enzymes, proteins are broken down into organic amines, sulfides, skatin and aldehydes, which have a foul smell.

Acerbity. Carbohydrate-rich foods such as grains, sugars and their products will produce a sour or rancid taste with their own characteristics when spoiled. Carbohydrates break down to produce monosaccharides, disaccharides, organic acids, alcohols, and aldehydes, resulting in a sour or alcoholic taste.

Rice spoiled, pastries sour, and fruit rot are examples of such spoilage.

Musty smell. Foodstuffs contaminated with mold, such as grains, peanuts, bread, cakes, rice, and steamed buns, often become moldy and spoiled in a warm and humid environment. Mold can produce toxins, such as the familiar aflatoxin.

2. Can you eat spoiled food when boiled?

Food can spoil if it is not stored properly, and many people think that spoiled food can be eaten after boiling, which is not true.

The toxins secreted by bacteria before they enter the human body are very resistant to high temperatures and are not easily destroyed and decomposed. Therefore, this method of using heat and pressure to deal with spoiled food is unscientific, and the spoiled food must be poured out, and it must not be lost because of small things.

Finally, let's learn about the dangers of spoiled food.

3. The hazards of spoiled food

These spoiled foods usually produce some toxins secreted by bacteria, which will interfere with the body's metabolism and eventually affect the normal function of human tissues. For example, in rotten fruits, the decocylotoxin produced can paralyze the nerves, and can also affect the normal function of the kidneys and promote premature aging.

What's even more terrifying is that some moldy foods will also produce some carcinogenic toxins, such as aflatoxin, variegated aflatoxin, patulin, red penicillin, b fumonisin, hethoxin, etc.

For the sake of our health, we must not eat spoiled food, and don't lose a big deal because of a small thing.

4. How to identify spoiled milk

If you want to better judge whether the milk is spoiled, you can heat the milk, if there is sediment or curdling like tofu flowers, it is spoiled and molded milk.

Note: This identification method is suitable for fresh milk, high-calcium milk and flavored milk beverages, while yogurt and lactic acid bacteria beverage eggplant chains should not be heated.

At the same time, sterile milk stored at room temperature may also appear bad, mainly manifested as swelling or acid packing, and the contents become tofu flowers or water residue separation.