Chapter 3 of Class 5 EVS (Our Wondrous World), The Mystery of Food, follows Detective Disha as she investigates why food spoils, and explores preservation methods old and new.
Key Concepts
Why food spoils: microbes need moisture, air, and the right temperature to grow and multiply on food.
Cooking food: makes some raw foods safer and easier to digest, while other foods (like fruit) are safe to eat raw.
Preservation methods: traditional — drying, salting, smoking, fermenting; modern — freezing, canning, pasteurisation.
Quick Recap
- Removing moisture (drying) or lowering temperature (freezing) both slow down microbe growth, which is why they preserve food.
- Eating spoiled food can cause an upset stomach or worse illness.
Common Mistake to Avoid
Assuming all preservation methods work the same way — drying and salting remove the moisture microbes need, while freezing and pasteurisation work by temperature control, not moisture removal.
Frequently Asked Questions
Why does salting help preserve food?
Salt draws moisture out of food, and microbes need moisture to grow, so removing it slows spoilage.
What is pasteurisation?
A modern preservation method that heats a food (commonly milk) to a specific temperature to kill harmful microbes without fully cooking it.
Full walkthrough: Chapter 3 Solutions · Extra Questions.
