People often assume that any food past its expiration date should be thrown away. In reality, many packaged foods can still be safely consumed after the date printed on the packaging, especially when the food has been stored properly and remains unopened. However, experts say there are three types of foods that must be discarded immediately once they have expired.
The “best by” and “sell by” dates marked on food packaging bags typically indicate the best quality period of the food rather than a safety deadline.
However, the expiration date should not be completely disregarded. Factors such as storage conditions, whether the packaging has been opened, and the type of food play crucial roles in determining if the food is still safe to eat. Some foods can quickly become breeding grounds for harmful bacteria once they have passed the recommended date, and conducting a “taste test” at that point is like playing a dangerous game.
Below are some information compiled by the lifestyle website marthastewart, regarding three types of expired foods that experts recommend disposing of, and which date labels need extra attention.
If you have soft cheeses (such as Brie, mozzarella, and goat cheese) past their best before date, food scientist Dr. Bryan Quoc Le suggests getting rid of them, even if they do not appear or smell spoiled.
“No matter the appearance and smell, these foods often are not safe because they could harbor dangerous microbes. Even a small amount of these microbes can be pathogenic, especially for individuals with weakened immune systems,” Le explained. He pointed out that harmful microbes such as E. coli, Salmonella, and Listeria are major concerns.
A study published in the Journal of Food Science and Technology also confirmed this point. The study indicated that even with proper packaging measures like vacuum sealing, the shelf life of soft cheeses can only be slightly extended.
The safety of these cheeses is also highly affected by temperature fluctuations: repeatedly taking them out of the refrigerator, improper cooling, or storing them on the refrigerator door (where temperature fluctuations are greater) can accelerate bacterial growth.
Food safety expert Mario Hupfeld said the key is to minimize the time spent in the “danger temperature zone” (5 degrees Celsius to 60 degrees Celsius) as bacteria can rapidly multiply in this temperature range, and even a brief negligence could significantly increase the risk.
Research has found that bacterial growth on red meats is only slowed down rather than stopped, even with proper packaging and storage.
The situation is similar for seafood (especially fish). Researchers found that refrigeration alone cannot guarantee the ideal shelf life for seafood. The research pointed out, “Storing seafood at freezing temperatures is currently the only technique that ensures long-term preservation.”
Le emphasized that seafood and meats are both susceptible to bacterial growth and toxins, meaning that once they are expired, they should be considered foods with a very short safe consumption window.
Storing cooked rice and pasta also poses risks, especially when they cool slowly, or if they are left at room temperature for a long time before being refrigerated.
A study from the Institute of Agricultural Chemistry and Food Technology in Valencia, Spain in 2021 emphasized that the spores of Bacillus cereus can remain alive during the cooking process and can linger in starchy foods (like rice or pasta); under suitable conditions, they can proliferate significantly and produce toxins, which reheating does not always destroy.
Hupfeld noted that this risk is prevalent in daily cooking.
“They have higher water content compared to other foods,” he explained. Combined with the practice of slow-cooking and batch cooking, this provides ideal conditions for bacteria to proliferate significantly before the food is cooled.