Can't eat food that's one day past its expiration date? These foods have no expiration date, don't waste them!

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Food cannot be eaten if it is one day past its expiration date, even if it does not show any signs of spoilage on the outside.

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What is the shelf life?

Most foods on the market have expiration dates marked on them. When you buy something, you can clearly see the production date and expiration date of the food by looking at the label. The best-before date is if you eat it during this period.

Regarding the shelf life, my country's "GB7718-2011 General Rules for Pre-packaged Food Labeling" states that products within the shelf life are completely suitable for sale. The quality of food within this date is the best. When the shelf life is exceeded, the food may deteriorate and the nutrition will decrease accordingly.

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How is the shelf life determined?

Many people may wonder how the shelf life on food packaging is determined? Is it just written randomly based on life experience?

This is not just a random statement! The shelf life is a guarantee of food quality, and it is not easy to determine the shelf life of a certain type of food.

In 2017, the China Food Industry Association issued the group standard "General Guidelines for Food Shelf Life", which clearly stipulates the general requirements for shelf life and how to determine the shelf life.

To determine the shelf life of a product, manufacturers must first conduct a food shelf life stability test. The basic procedure for determining the shelf life has six steps: determining the plan, designing the test method, implementing the plan, analyzing the results, determining the shelf life, and verifying the shelf life. [1]

Source of chart: T/CNFIA 001-2017 General Guidelines for Food Shelf Life

In addition, other factors that affect food safety risks need to be considered, such as microbial risks at different storage temperatures.

Therefore, the shelf life on food packaging is not written casually. Food within the shelf life can be purchased and eaten with confidence. If the product is expired, the seller is not allowed to continue selling it, and it is not recommended for consumers to buy it.

Can expired food still be eaten?

Expired food may go bad, but it does not necessarily go bad. The shelf life of food is not the last date it can be eaten, it just tells you that if you eat it before this date, its quality, taste, nutrition retention, etc. are the best.

Even expired food can mostly be eaten as long as it is not rotten or spoiled and has no peculiar smell, especially foods with relatively low water content and foods with high sugar and salt content. Their shelf life is generally longer, basically reaching more than 6 months, such as beef jerky, biscuits, instant noodles, egg rolls, candied fruits, ham, seasoning sauce, hot sauce, canned food, etc.

As for some foods with a short shelf life, due to incomplete sterilization, microorganisms are easy to reproduce. Even if they are only one or two days expired, it is best not to eat them for safety reasons. For example, pasteurized milk, fresh juice, freshly baked cakes or bread, cold fresh meat, etc.

However, it should be noted that even if some foods have not expired, they may no longer be edible if they are not stored properly.

Many foods in our lives need to be refrigerated and stored away from light. However, if you do not store them according to the instructions on the package after opening, but instead leave them at room temperature or in direct sunlight, this will accelerate the reproduction of microorganisms and cause the food to spoil.

For example, oyster sauce, which is commonly used in the kitchen, has a label that clearly states that it must be refrigerated after opening, but many people just store it at room temperature. Another example is the label on cooking oil that states that it needs to be sealed and kept at room temperature away from light. If it is not sealed or kept away from light after opening, or if it is placed directly on a sunny balcony after purchase, this will accelerate the deterioration process and the oil may become inedible before the expiration date.

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These foods have no expiration date

Honey: There is a popular saying that honey can be preserved forever. Some people even ask, "Can honey be preserved for thousands of years?"

Ah... this... Does a jar of honey have to be passed down from generation to generation? Can't something else be passed down?

In fact, honey is very durable in storage. 75.6% of honey is sugar, including glucose and fructose, and only 22% is water and other small amounts of nutrients. Under sealed conditions, the water activity of honey is very low, and the growth of microorganisms will be inhibited, so the shelf life is very long. A can of unopened pure honey has a very long shelf life. But can it be stored for thousands of years? Theoretically, it is unlikely.

It should be noted that to preserve honey, you only need to seal it and place it in a cool and dry place, not in the refrigerator. Otherwise, it will solidify and white crystals will appear, which will be difficult to eat.

Although pure honey is very durable, there is a shelf life on the packaging of honey for the following two reasons:

① The General Rules for Pre-packaged Food Labeling stipulates that only alcoholic beverages with an alcohol content of 10% or more, vinegar, edible salt, solid sugars, and monosodium glutamate do not need to have a shelf life marked on the packaging. Any other food must have a shelf life, and honey is no exception.

② Honey needs to be opened and eaten after it is purchased and brought home. Honey may also be mixed with water and other pollutants, which increases the chance of air contact and microbial invasion and reduces its shelf life.

Salt: When buying salt, many people will find that there is only a production date on the salt packaging, but no expiration date! Is it missing from the label? No! According to the "General Rules for Prepackaged Food Labeling", salt does not need to be labeled with an expiration date. However, some salts will be labeled with an expiration date, and these salts generally contain additional ingredients, such as sea buckthorn salt, pink salt, etc.

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White sugar: According to the General Rules for Prepackaged Food Labeling, white sugar does not need to be labeled with a shelf life. This is because white sugar has a stable chemical property, low water content, and high sugar content, which is not conducive to microbial reproduction and is very durable in storage. However, it needs to be sealed and placed in a cool and dry place, otherwise it is easily affected by moisture, which increases the risk of microbial contamination.

Even though white sugar has no expiration date, it is not recommended to buy too much at one time. Although it is not easy to spoil, it may oxidize and turn yellow during long-term storage. This may be due to the high content of trace pigments such as isoprene derivatives and polyphenol derivatives that change color during storage. The Maillard reaction of partially hydrolyzed peptides with the aldehyde and ketone groups of reducing sugars also plays a role. [2]

Vinegar: According to the General Rules for Prepackaged Food Labeling, vinegar does not need to be labeled with a shelf life. Vinegar has a relatively low pH value, which can inhibit the growth of microorganisms and is durable in storage. However, vinegar is very volatile, and if stored for too long, its edible value may decrease and its taste may deteriorate. It must be sealed after opening.

Wine: The General Rules for Prepackaged Food Labeling stipulates that for alcoholic beverages with an alcohol content of 10% or more, the shelf life does not need to be marked. In life, we often hear people say "aged wine has a strong aroma". New wine tastes spicy and irritating, while aged wine tastes sweet and soft.

This is because the alcohol content in new wine is higher, and the grassy, ​​lees and alcohol flavors are stronger than those in aged wine; while the trace aroma substances in aged wine are richer, most esters, organic acids, aldehydes and ketones are higher in aged wine than in new wine, and the intensity of caramel aroma, fruit aroma, sweet aroma and sourness is higher in new wine. The higher the aroma substances, the more fragrant the wine is, and the higher the sensory evaluation is, which is also an important reason why people are keen on aged wine. [3]

Summarize

The shelf life of food means that the quality, taste, and nutritional retention of the food are best if eaten before this date.

Therefore, even if food has passed its expiration date, it is not necessarily inedible. As long as it is not spoiled or has no peculiar smell, most of it can still be eaten, especially foods with relatively low water content and foods with high sugar and salt content.

However, some foods with a short shelf life can easily allow microorganisms to multiply if they are not thoroughly sterilized. Even if they are only one or two days expired, it is best not to eat them for safety reasons.

References:

[1] T/CNFIA 001-2017 General Guidelines for the Shelf Life of Food

[2] Wang Yongfang, Guo Pengjin. Analysis and control of discoloration substances in sugar during storage [J]. Guangxi Light Industry, 2003(5):35-37

[3] Sun Xizhen, Xiong Yaqing, Liu Jiahuan, Qian Quanquan, Jie Qianqian, Wei Shuxia, Chen Yanhe. Analysis of sensory characteristics and aroma substances of new and aged light-fragrance liquors[J/OL]. Food Science: 1-10[2023-03-09]. http://101.43.173.17/kcms/detail/11.2206.TS.20221207.1548.010.html

Author: Xue Qingxin, registered nutritionist

Review | Chen Ran Associate Research Librarian (Science Communication)/Senior Engineer, COFCO Nutrition and Health Research Institute

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