Packages use two different phrases, and they do not mean the same thing. An expiration date is a safety limit; the product should not be consumed after that date. A best-by date is a quality limit; the product may still be safe after that date, but its flavor and texture may decline. Both dates apply as long as the package has not been opened and the product has been stored at the correct temperature.
Two different phrases appear on packages and are often mistaken for the same thing. The first is an expiration date; it is used for perishable products and indicates a safety limit. The second is a best-by date; it indicates the period when the product is at its best quality. The difference is not a minor detail: one concerns safety, while the other concerns only flavor and texture. That is why seeing which of the two phrases is printed matters as much as the date itself. So two products sitting side by side on the same shelf are not necessarily subject to the same rule.
Products such as milk, yogurt, fresh cheese, and cream generally fall into the first group. Do not consume these products after the date, even if they look fine. Shelf-stable milk and some aged cheeses may fall into the second group; in that case, the product does not become dangerous immediately after the date, but its flavor may begin to decline. The package clearly indicates which date applies. The longer a cheese is aged, the more durable it becomes, so its date ranges are longer, too.
Both dates have a hidden condition: the package must be unopened, and the product must have been stored at the correct temperature. The printed date no longer applies to a carton of milk once it has been opened; from then on, a much shorter time period begins. The same is true for opened yogurt and cream. So write the opening date on the container and decide based on that. The package often also states how many days the product should be consumed within after opening.
Temperature is the second hidden condition. If the cold chain is broken between the store and home, the product may not last until the date printed on the package. Leave dairy products until the end of your shopping trip and refrigerate them as soon as you get home. Their location in the refrigerator matters, too: the door shelf is the warmest area, so store perishable products on the interior shelves instead. Check the refrigerator temperature from time to time with a thermometer to see whether this condition is being met. The door shelf also warms up every time it is opened, so it is better suited to drinks and sauces.
The date alone is not enough, either. A product may have spoiled if it was stored poorly, even before its date; check the package before opening, then check the smell and appearance afterward. A swollen lid, bulging carton, separated appearance, or sharp odor is a reason to discard it, regardless of the date. When shopping, choose the product at the back of the shelf with the later date. In the refrigerator, do not put new purchases at the front and older ones at the back; arrange them the other way around.
A Note for Readers
This content is for informational purposes only and is not a substitute for medical advice. Consult your doctor before making any decision about your health.