Canned goods generally through three ways **** the same collaboration to prevent food spoilage:
Sterilization
Whether it is food or canned goods need to be sterilized, eliminating the bacteria as well as bacterial spores after the bacterial reproduction will not be there. However, it is unlikely that all of them will be eliminated, but what can be done is basic sterilization so that the food can be kept for as long as possible.
Sealing
There are also a lot of bacteria and bacterial spores in the dust in the air, and the bacterial spores are like the seeds of a tree, which are very hardy and resistant, and can float in the wind. That's why canned goods are vacuum sealed.
Preservatives
The canned goods have preservatives, because the bacteria to the appropriate environment will rapidly multiply, even if there is only one bacterium, due to the division of the reproduction, so it will soon be able to become countless. And preservatives can effectively inhibit the survival of bacteria, so that the few bacteria can not survive, food preservation time is long. [1]
The more commonly used food preservatives are sorbates and nitrites, of which potassium sorbate is basically non-toxic, but nitrites are carcinogenic and more problematic.
Sanitary standards for food additives provide that no additives should be added to canned fruit. But some low-quality canned goods added potassium sorbate, carmine, lemon yellow and other synthetic colors, but also with sweeteners, industrial-grade soda ash, industrial hydrogen peroxide to the coconut "bath".
When choosing canned fruit, first look at the appearance of canned fruit pulp. Normal canned yellow peach fruit, the color of its products should be less uniform, there is a golden yellow, and a little with a greenish color. Fake canned yellow peaches have a perfectly uniform pulp with a nice looking color. Normal canned yellow peaches should have a colorless broth, while cans that have been dyed have a yellow broth.
Canned strawberries, on the other hand, are chosen by looking at the broth first. If the soup is very red, it is dyed, and if the soup is slightly pink it is normal. At the same time, stained canned strawberries, its pulp is immature, will be relatively small.
While homemade canned fruits can be used safely, they should not be stored for a long time, so it is best to consume them within a short period of time.