How much do you know about the shelf life of food

After the "May Day", the weather gradually became hot, and the topic of "shelf life" caused heated discussions among the public

What are the reasons for food spoilage

There are two most common causes of food spoilage, one is microbial activity, and the other is fat oxidation

To inhibit microbial reproduction, the easiest way is to reduce the water required for microbial activity, such as reducing the water activity in the food, or adding a lot of sugar and salt to the food

Experts said that taking instant noodles as an example, the water activity in instant noodles is low, and microorganisms cannot proliferate in large quantities

Natural fats undergo oxidation reactions automatically under aerobic conditions

Oxidatively spoiled food not only tastes bad, but also contains many substances that are easy to generate free radicals, as well as toxic and harmful oxidative decomposition products

Instant noodles, cookies, potato chips, rice crackers, peanuts, melon seeds, cooking oil, sesame sauce.

Unfortunately, fat auto-oxidation is a difficult problem to solve completely

Can it be eaten after the expiration date?

Experts said that the shelf life does not mean that it can only be eaten within the specified time range, but "the quality assurance period of the product under normal conditions", that is, during the shelf life, the best taste and quality of the food can be guaranteed, so consumers are advised to use it during the shelf life.

Staple food staple food can be divided into two categories according to the water content: bread and steamed bread with more moisture; biscuits with less moisture

Canned foods are all sealed and packaged, and the shelf life is generally longer, and some are more than 2 years

Dairy products The shelf life of dairy products varies from 48 hours to 7 days depending on the process and packaging

If the meat product is vacuum-packed, the shelf life can be up to 3 years.

The chemical properties of sodium chloride in edible salt are very stable, and they generally do not deteriorate when stored for a long time

Honey Honey contains less water and high sugar content, and most microorganisms cannot reproduce

Under normal conditions, rice will not go mildew after being stored for a long time

Experts say that there are some foods that are not suitable for the refrigerator, otherwise they will accelerate the deterioration
.
These foods are as follows:

Potatoes and sweet potatoes are rich in starch, and low temperature will decompose the starch in potatoes, affecting the taste; and the refrigerator has a refrigeration function, and the environment is humid, which is easy to accelerate the germination of potatoes, and the content of solanine in the germinated potatoes will increase.
, After eating, it may cause poisoning, nausea, vomiting, abdominal pain, diarrhea and other symptoms
.

Although the temperature of garlic and onion in the refrigerator is low, the humidity is also high.
Garlic and onion are prone to mildew and deterioration in a humid environment.
Moreover, these two types of food have a strong smell.
If they are cut and placed in the refrigerator, other food will be stained Taste the garlic and onion
.

Dry products such as coffee, tea leaves, and coffee have extremely low water activity after drying, and microorganisms cannot reproduce
.

In addition, after the expiration date of refrigerated food and fried food, it is easy to have safety hazards such as excessive microorganisms, excessive heavy metals, and excessive peroxide value, and should not be eaten
.

　　(Comprehensive arrangement by Qu Yuening)

　　"China Food News" (May 05, 2022 06 edition)

　　(Editor in charge: Gao Jiaodi)