What Is Decomposition in Food?
4 Minutes
Food spoilage for kids: learn why bread, bananas, cheese, and milk spoil, and how to store them properly. A short science lesson in English.
- How fungi, yeast, and bacteria spoil food like bread
- Why enzymes turn ripe bananas black and cheese dries out
- Storing bread in the fridge, boiling milk, and sealing milk powder
What this lesson teaches
Decomposition in food is the process where food breaks down and loses its freshness because of microorganisms, natural chemical reactions, or loss of moisture. This breakdown changes the appearance, texture, and quality of food items like bread, bananas, cheese, and milk.
How microorganisms affect food
Microorganisms are tiny living things that can cause food items to decay. While some microbes can cause health issues like stomach ache and diarrhea, others are helpful, such as the small amounts of yeast bakeries mix into dough to make bread soft. If bread is not looked after properly, fungi multiply and show up as green growth that spoils the food. Other foods are spoiled by bacteria or by airborne microorganisms that settle onto unprotected items.
Spoilage from enzymes and drying
Not all food decay comes from living microbes attacking from the outside. A raw banana contains internal substances called enzymes that help it ripen, but these same enzymes eventually move outward and turn the ripe peel black. Physical changes can also ruin freshness, such as when water evaporates out of cheese over a few days, causing it to become dry and hard.
The role of temperature in spoilage
Temperature heavily influences how fast food decomposes. When surrounding temperatures are high, milk left outside quickly turns bad because microorganisms thrive in the warmth. Cold temperatures in a refrigerator prevent milk from spoiling and stop green fungi from growing on bread. High heat is also useful, because boiling fresh milk destroys the many microorganisms living inside it.
Steps to keep food fresh
- Keep bread in a cold refrigerator so green fungal patches cannot grow.
- Boil liquid milk to stop the microorganisms living inside it from spoiling the batch.
- Seal milk powder inside a tight can or container to block microorganisms floating in the air.
- Store cheese properly so its natural water content does not evaporate away.