What is it called when food goes bad?

In this brief guide, we will answer the question “What is it called when food goes bad?”, tell you how to spot spoiled food, and discuss whether ‘best before’ dates indicate that the food has gone bad.

What is it called when food goes bad?

There are many terms that can be used to tell when ‘food goes bad’. Refer to the following list to find out.

Rotten food

‘Rotten’ can be used to describe food that has started to decompose. It can be used for items like fruits or vegetables. Even meat can start to rot. Rotten food will give off a horrible smell and may also have a gooey, slimy texture.

Spoiled food

We say food has ‘spoiled’ when it alters its taste, the texture, smell and has discolorations. It is a very basic term that can be used to describe food that is not good for consumption.

Stale food

Food like chips, once opened and placed for a few hours, get soggy and lose their crispiness. This is what we refer to as ‘stale’. 

Moldy food

Every so often, mold will grow on food, especially on bread. This is what we refer to as ‘moldy’ food. Mold makes the food go bad. You can not consume food that has mold on it to avoid any health risks.

How do you know if something is spoiled?

You can tell if something is spoiled by looking at some features listed below. Most often, you will be able to tell that a certain food has spoiled just by looking at it. Other times, it may not be as easy to tell if food has spoiled because some bacteria do not change the way how food looks or tastes but it in fact is present. 

Let us look at some signs of spoiled food.


You can tell if something has gone bad if it smells off and rancid. The smell may be so strong that you get a strong whiff of it as soon as you open the refrigerator or the container that it was in. The smell of food should be the same as it was when you cooked it or before you put it in the refrigerator.


Spoiled food will have some discoloration on it such as black or bluish black or even brown. Now it could be because of some chemical reactions like in the case of apples or simply because of bacteria and its toxins.


Mold is almost always visible on food when it has spoiled. This type of spoiled food should be discarded immediately.


Changes in texture also indicate food spoilage. If you notice any slimy, gooey or soggy textures, throw the food out.


If all else looks fine visually, take a taste test. Test to see if it tastes the same or has the taste altered. Altered taste usually means spoiled food.

For example cream and yogurt taste sour when they go bad. So does the milk.


Frost on top of frozen food indicates freezer burn. Freezer burn alters the texture and taste of food. So frost is a sign that the food has gone bad.

Gas Bubbles:

Gas bubbles spotted at the bottom of jarred or canned food that travel upwards is also a sign of spoilage. 

Do expiry dates and best before dates indicate spoilage?

The ‘best before’, ‘sell by’, ‘use by’ dates are just provided by the manufacturer to give you an idea about the amount of time that a certain product will remain in its optimum condition. 

After this time, the food may lose its texture or alter the taste but it necessarily does not get spoiled. 

The food generally lasts longer if you store it properly and in the fridge. Lower temperatures arrest the growth of pathogens making the food safe to consume for longer periods of time.

Processed foods have preservatives added to them so they have a longer shelf life. They are even safe to consume weeks after their use by dates.

Be careful with perishable items. For example eggs and dairy products like milk tend to go bad quickly and can cause food poisoning so it is better to throw these things out after their expiry date.

Learn more about expiry dates here.


In this brief guide, we answered the question “What is it called when food goes bad?”, told you how to spot spoiled food, and discussed whether ‘best before’ dates indicate that the food has gone bad.



Hi, I am Charlotte, I love cooking and in my previous life, I was a chef. I bring some of my experience to the recipes on this hub and answer your food questions.