Science Facts

Why Is Expiration Date Important? – Food & Medicine

Expiration Date

You have got a bad stomachache, then where do you head to? Most probably to medicine. And the next thing before using is checking the expiry date, if it’s out of date or not. It raises the question and tickles the brain, “Why is there an Expiry Date?”

First, to know the science behind it, we need to know why and how things expire? And most of all, why is there a need for the expiration of any product. We will mostly talk about products like food, water, medicines that have a biological impact. You can say the expiration period is like the shelf-life of food products. Why do things expire? A product’s real expiration date is complex to predict because it can be affected by everything from the sanitation of the factory to the temperature of the fridge.

Why is expiration date important?

The expiration of many products is predetermined, which means we know the exact time, but it’s not true for all cases. For example, You bring home fresh broccoli and leave it in the open. What you will find is stale food dominated by microbes. You will not eat this food because it’s stale and not fresh. So, in a sense, it has expired. That is why we have to understand the real reason for expiration, like medicines and packaged drinking water.

They have real expiry dates printed on them, and there is a reason for that. Most food products have a peak quality, which is the most nutritional value before expiration. It is said to consume the food before it expires. Most chemical reactions occur at room temperature, but they can also be boosted by various conditions, like catalysts and temperature. So, the same is the case with food products.

  • Sell-by-date: This date tells a storehouse long to display that product for. According to the USDA, this is in no way the expiration date.
  • Use-by-date: The date the manufacturer of the product feels said product will be at its peak.
  • Best-if-used-by-date: This date is for the best flavour or quality. But the USDA points out this is not a safety date.
  • Closed or Coded dates: It’s the packing number that is used for the manufacturer.

Mostly, food products are frozen because a deduction in the temperature reduces the rate of the chemical reaction. The lesser the chemical reactions more are the shelf life. You must have read in many articles, ” Keep in a cool, dry place.” That is because cool places reduce chemical reactions and dry places have no moisture. It also reduces chemical reactions.

But what kind of chemical reactions are we talking about here? Food products get exposed to air and various other microorganisms. Microbes feed on our food and release broken-down sugars. Most of these sugars are harmless, so expired food doesn’t mean it is unsafe to eat, though the quality and nutritional value are deprived. In this case, if medicines too, the expiry date refers to the time in a particular environment.

For example, A medicine lasts for 10 Days at 20°C temperature, but if we change it to 10°C, it will last longer. But the question remains: What if no microbes attack the food? Then will the food have a very long shelf life? To know that, we need to know how microbes deprive the nutritional value of food products. Most microbes feed on the food left by oxidation. It means the food has become stale because of chemical reactions with oxygen. They release enzymes that disturb the quality of our food.

Enzymes speed up chemical reactions. They can release foul odors and change shape, but that doesn’t mean the food becomes inedible. They can be eaten, but the quality is deprived, and so is the Nutritional Value. But What if no microbes attack the food? Then, the shelf life increases. That is why we refrigerate our food. But still, it is in contact with air and so with oxygen and slowly gets stale. Refrigeration stops the growth of microbes.

For example, in our broccoli example, if we leave food in the open, it gets stale fast, whereas if we had refrigerated it, it would have been consumable for a longer period. If we completely stop oxygen from reaching the food. You have almost a very long shelf-life.

Medicines should always be taken within the expiration date. Otherwise, they will not prove effective in treatment. However, with food, the expiration date does not necessarily mean ‘expire.’

Best before date vs expiry date

In Canada, the best before date must be on all products with a shelf life of fewer than 90 days. It means on every package of food that is somewhat perishable. You’ll find the year, month, and day on that product. The manufacturer estimates that the food will remain wholesome, palatable, and will retain its nutrient content. It’s not an estimation of safety, though. What does it mean that it is legal to sell a product that has gone over its best before date?

It is estimated that it might not be as fresh as it would have been sold within the best before date. The expiry date is when the government concludes that or regulates that this food cannot be sold. And there are specific subsets of food with expiry dates on them, and not all food has expiry dates. The expired gate relates to the potency of the nutrient materials in food. So specifically, where you would find expiry dates on food products would be foods like infant formula liquid diets prepared for special medical conditions or meal replacements. And they include dietary supplements as well.

So when an expiry date is placed on these categories, they cannot legally be sold because there will be a change in the nutrient content. And these categories of food are types of food that have specific nutritional functions. The other category of food that consumers will come across will carry us a slightly different estimate of best before. That is a package on the date.

It’s required on all fresh meat and poultry and packaged on the date that correlates with information. That is usually made available to consumers in a meat department in the form of a poster. Here, the packaged date is considered in the light of information on a specific type of meat poultry you’re purchasing. And the retail store will list the periods that these products can be held in refrigerated storage area following packaged on date period.

The sell-by date is important because retailers take the product off the shelf on a specific date. So a consumer won’t buy an out-of-date product. Dairy products can be used about 5 to 7 days after their sell-by date used by the retailer. Eggs also have an extended shelf-life, generally 3 to 5 weeks.

Finally, meats and cheeses should be used within 4 days of the product being sliced at the deli. That date will generally show on all deli labels. When it comes to shelf-stable products, pantry goods, the code dates are primarily for freshness and quality issues. Things such as crackers, cereal, and pasta can gradually decrease in quality.


In the case of food products, expiration dates are partly useless, but they are important in medicines. So, feel free to eat those chip packets after expiration, but remember, always try to gobble up food before it expires for taking full energy. In the case of medicines, don’t hesitate, see the Expiry Date! So the next time you get a stomachache, remember why your medicines expire and take those medicines before time runs out!

Frequently asked questions

Which food never expires?

  • Honey.
  • White Rice.
  • Salt.
  • Soy Sauce.
  • Sugar.
  • Dried Beans.
  • Pure Maple Syrup.
  • Powdered Milk.

Is it safe to drink expired milk?

Milk is pasteurized, which means any harmful bacteria was removed long before it hit the shelves. Even though it might not taste great. The safety risk of drinking spoiled milk is virtually zero.

Why does water not expire?

Water has a very long shelf-life, so it technically does not expire. It is safe to consume water after expiration because drinking water’s shelf life changes with the container it is kept in. For example, in plastic water bottles, the expiry date refers to the plastic which holds the water. After the expiry date, plastic will start degrading, and so disturbing the quality of water. But if we take a glass container, the shelf life of water will be longer. It depends upon the container used to store water.

You can still consume them. They will not cause food poisoning. There will have the least nutritional value. And so, they are just an estimation of the time. They can change depending upon the conditions, like temperature.

Read More: How Does Cold Medicine Work In Body?

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