Can you eat food a day or two after it expires? Is food safe during the expiration date?

Where does the expiration date statement come from?

In the face of unopened food at home that has just passed its expiration date, many people have the problem of "it is a pity to throw it away after expiration, and it is a pity not to throw it away, and I am afraid of getting sick if I don't throw it away". However, what is the expiration date? What does shelf life mean and is it the "gold standard" for measuring spoilage?

Let's start with the conclusion: the expiration date is not the same as the expiration date of the food.

Professor Fan of the College of Food Science and Nutritional Engineering of China Agricultural University explained that the significance of setting the shelf life of food is-

On the one hand, it reminds sellers and consumers that there may be a risk of deterioration in quality, deterioration and even spoilage after food has been stored beyond its shelf life.

On the other hand, it is used to define the food safety responsibilities of all parties. If the food is consumed within the set shelf life and there are quality and safety problems, the manufacturer or distributor needs to be held responsible. Once the expiration date has passed, the food cannot be legally sold.

The vast majority of pre-packaged foods need to be marked with an expiration date, which is determined by the manufacturer on the basis of shelf life experiments and in accordance with industry practices. The so-called pre-packaged food refers to the food that is pre-packaged or made in packaging materials and containers.

Fresh produce such as fresh vegetables, fruits, meat, fish, and eggs are not considered pre-packaged foods. Bulk foods such as bulk grains, as well as freshly prepared and sold foods such as restaurant food, street food, and ready-made dumplings, are also not pre-packaged foods and are not mandatory to label the expiration date. The shelf life of these foods needs to be judged according to life experience, among which it is best to eat the catering food immediately after purchase, otherwise it should be frozen in time.

What's new in the new standard?

The new "General Principles for the Labeling of Prepackaged Foods" (GB 2025-0) and the "General Principles for the Nutrition Labeling of Prepackaged Foods" (GB 0-0) have "upgraded" the food labeling, and the main changes are:

1. Adjust the expiration date to the "expiration date". Through this labeling, you can directly know when the food expires, and there is no need to calculate the production date combined with the expiration date.

2. Standardize the shelf life labeling format. It is clearly marked in the order of year, month and day, and the information display is more intuitive.

3. To reduce food waste, the new standard encourages the labelling of "shelf life for consumption". If the consumer does not finish the food within the expiration date after purchase, he or she can choose to continue to consume it within the "shelf life", provided that the food is stored in accordance with the storage conditions indicated on the label.

Have you fallen for these misconceptions about the shelf life?

Myth 1: All food products must have an expiration date.

The spoilage of food is caused by the proliferation of microorganisms, and the deterioration of food such as "hala taste", "old oil taste" and "artemisia taste" is related to fat oxidation. If these two problems are not present, the food can be stored for a long time.

Liquor, salt, sugar, honey and other foods can be stored for many years without marking the shelf life due to the high content of alcohol, salt and sugar, and there is no problem of fat oxidation.

Myth 2: The longer the shelf life, the more preservatives

The shelf life of food is related to the characteristics of the food itself, the production process and the storage conditions. Traditional methods such as drying (removing moisture), salting, sugaring, and low temperature are all ways to achieve long-term preservation of food.

For example, in ancient times, it has been found that dried foods such as dried meat, dried fish, dried vegetables, and dried fruits, as well as salted fish, salted meat, pickles, bean curd and other foods with high enough salt content, can be stored at room temperature for more than a year for a long time without spoiling, and no preservatives need to be added.

Through the technology of high temperature sterilization and aseptic filling, all the microorganisms inside the package are killed, and at the same time, the microorganisms outside the package cannot enter, and the shelf life of the food can also be greatly extended. Canned food, soft cans and other products are produced using this principle.

In addition, freezing at low temperatures and storing at freezing conditions below -18°C can also prevent the proliferation and toxinization of microorganisms, extending the shelf life of food to one year or even longer.

Myth 3: If the expiration date is exceeded, you have to throw it away

Generally speaking, there is a certain amount of margin for the shelf life set by food manufacturers. Especially for food with a long shelf life, it is a common situation that the "shelf life" marked on the package has not spoiled. If easily discarded, it can cause serious food waste. At this time, whether it can be eaten or not needs to be judged by consumers based on life experience. If the flavor, color, taste, etc. have not changed, it is still safe to eat.

For example, a certain can has a shelf life of two years, and it expires for two months at home. From the outside, the shell of the jar does not swell, and after opening it, there is no peculiar smell, and the taste and texture do not change when you taste it, so you can eat it. Although the vitamin content decreases over time and the flavor is not as good as when it was first produced, there are no food safety issues associated with eating it.

For another example, the rice, millet, beans, etc. bought at home, after more than a year, there is no moisture, mold, insects, etc., at this time there is no safety risk to continue to eat, but the aroma is not as good as the new grain of the year, and the taste value has decreased.

Myth 4: As long as it is within the shelf life, it must be safe

Many people only look at the expiration date but do not pay attention to the shelf life. For example, a pasteurized milk product that needs to be refrigerated at 6~0 °C may lead to early spoilage if it is not stored in accordance with the refrigeration conditions and left at room temperature for a day or even a few hours.

Therefore, everyone is reminded to pay attention to the preservation conditions on food packaging, such as "refrigerated storage", "storage in a cool place", "avoid moisture", etc.

In addition, the expiration date of food sealed after sterilization and sterilization treatment can only guarantee the storage time before opening. After opening, food comes into contact with airborne microorganisms and cannot continue to be stored at room temperature for long periods of time. For example, the packaging of ketchup, soybean paste, mushroom sauce and other seasoning sauces often has the words "please refrigerate after opening".