When purchasing food, most consumers check the date printed on the packaging. However, how well do we understand:
What does this date mean?
Can the product be consumed on the date shown?
What happens the following day?
Is every product past its date unsafe, or do some products simply lose quality?
The answers to these questions cannot be found solely in the words “expiry date.” In food science, it is important to distinguish between food safety and food quality, while also considering the type of product, storage conditions, the condition of the packaging, and the specific meaning of the date shown on the label.
A Date on a Food Label Does Not Always Mean the Same Thing
Dates displayed on food labels are an important means of providing information to consumers, but different types of dates may serve different purposes. The European Food Safety Authority (EFSA) explains that there is an important distinction between the terms “Best Before” and “Use By.”
“Best Before” is primarily related to product quality. It indicates the period during which the manufacturer expects the product to retain its characteristic quality—including its taste, aroma, texture, and other properties—provided that it is stored under the appropriate conditions.
By contrast, the “Use By” date is directly related to food safety. It is applied to products that may pose a health risk if consumed after a certain period. According to EFSA, products bearing a “Use By” date are generally highly perishable foods, such as certain types of fresh meat, fish, and ready-to-eat foods. Consuming these products after the stated date is not recommended, even if they appear normal.
Why Can a Product That Looks Fine Still Be Unsafe?
One of the most common misconceptions is: “If it does not smell bad and looks normal, it must be safe.” Food microbiology confirms that this is not necessarily true. Some pathogenic microorganisms may be present in food without noticeably changing its smell, taste, or appearance. For example, Listeria monocytogenes, Salmonella, and certain pathogenic strains of Escherichia coli may grow or survive in a product without producing organoleptic signs that would allow consumers to detect the contamination.
The safety of perishable food cannot be assessed solely by looking at or smelling it. This is particularly important in the case of Listeria monocytogenes. One of the notable characteristics of this bacterium is its ability to multiply under certain conditions, including at refrigeration temperatures. Refrigeration does not automatically eliminate every microbiological risk.
Time After Opening
A manufacturer may provide instructions such as: “Refrigerate after opening and use within three days.” This recommendation is not arbitrary. Once the packaging has been opened, the product may come into contact with air, hands, kitchen surfaces, and other potential sources of contamination, increasing the associated risk. Consumers should therefore consider both the main date on the label and the recommended period of use after opening.
Can a Product Be Frozen Before Its Expiry Date?
In some cases, freezing can be an effective way to extend a product’s storage life, but timing remains important.
If a product is frozen while it is still safe and the appropriate conditions are maintained, freezing can slow the growth of microorganisms. However, freezing should not be regarded as a way to “fix” a product that is already contaminated or spoiled. Freezing inhibits the growth of many microorganisms but does not destroy all of them. After thawing, they may become active and multiply again under favourable conditions. Freezing does not make an already unsafe product safe.
Should Food Always Be Discarded Once the Date Has Passed?
The answer depends on the type of product. If a product bears a “Use By” date, consuming it after that date is not recommended from a food safety perspective.
If a product bears a “Best Before” date, passing that date does not automatically mean that the product has become unsafe. However, consumers should consider its storage conditions, the integrity of the packaging, and the manufacturer’s instructions.
For example, in the case of dry cereals or certain canned products, the primary concern after the date has passed may be a deterioration in quality rather than the automatic emergence of a microbiological hazard.
Nevertheless, assessing only the product’s smell, taste, or appearance is not sufficient to establish that it is safe.
What Should Consumers Do?
When purchasing and storing food at home, consumers should follow several simple principles:
Always check the date displayed on the label.
Determine whether the date relates to quality or safety.
Follow the storage temperature specified by the manufacturer.
Pay attention to instructions concerning use after opening.
Do not leave perishable food at room temperature for extended periods.
Do not rely on smell, taste, or appearance to assess product safety.
Exercise particular caution when purchasing perishable and ready-to-eat foods.
Conclusion
The date printed on food packaging is more than a simple set of numbers. It is an important tool for managing food safety and quality, and understanding it correctly plays a significant role in protecting consumer health.
The main distinction consumers should understand is the difference between “Best Before” and “Use By.” The former primarily concerns product quality, while the latter concerns food safety.
Food safety is not determined by the date alone. Other important factors include the type of product, storage temperature, maintenance of the cold chain, the condition of the packaging, the amount of time elapsed since opening, and compliance with the manufacturer’s instructions.
References
European Food Safety Authority (EFSA). (2020). Food Date Labelling: “Best Before” and “Use By” Dates. EFSA.
European Food Safety Authority (EFSA). Scientific Opinion on the Evaluation of the Need for a Quantitative Microbiological Risk Assessment for Foodborne Pathogens and Food Shelf-Life.
Codex Alimentarius Commission. (2022). General Principles of Food Hygiene CXC 1-1969. FAO/WHO.
World Health Organization (WHO). (2006). Five Keys to Safer Food Manual. World Health Organization.
U.S. Food and Drug Administration (FDA). Food Product Dating. U.S. Food and Drug Administration.
U.S. Department of Agriculture (USDA), Food Safety and Inspection Service (FSIS). Food Product Dating. USDA.
Food and Agriculture Organization of the United Nations (FAO). Publications and guidance on food loss, food waste, and food safety.
