The Mystery of Food

Key Concepts

Food Spoilage and Microbes

Food can spoil if left out for too long. This is caused by microbes (like mould), which are tiny living things that are all around us—in the air, water, soil, and even inside our bodies.

• Appearance: Microbes can form coloured patches (mould) on food.
• Smell and Taste: Spoiled food often has a foul smell and a changed taste.
• Visibility: Microbes are so small that they can only be seen through a microscope. A visible patch of mould is actually a colony of thousands of microbes.

Conditions for Microbial Growth

Microbes need three main things to grow on food:

1. Moisture: Water helps microbes thrive.
2. Air: Most microbes need air to survive.
3. Temperature: Warm temperatures help microbes grow faster.

Good Microbes

Not all microbes are bad. Some are very helpful:

• Curd Making: Certain microbes turn milk into curd.
• Fermentation: Microbes in the air help idli and uttapam batter rise and become fluffy.
• Digestion: "Good" microbes in our stomach help us digest our food. Curd and buttermilk are recommended for an upset stomach because they contain these beneficial microbes.

Food Preservation Methods

We can save food from spoiling by removing one or more conditions needed for microbial growth:

• Drying and Dehydration: Removing moisture by drying food in the sun (e.g., chillies, papad, aam papad).
• Pickling and Oiling: Covering food with oil stops air from reaching the microbes (e.g., mango or lemon pickles).
• Refrigeration and Freezing: Cold temperatures slow down or stop the growth of microbes (e.g., milk, vegetables).
• Adding Preservatives: Salt, sugar, and spices (like black pepper) have been used for centuries to keep food from spoiling.
• Canning and Packaging: Air-tight containers and cans keep microbes away from food.
• Heating: Boiling milk or heating butter to make ghee (which removes water) helps in preservation.

Digestion and Oral Hygiene

The process of breaking down food begins in the mouth:

• Chewing: Chewing food properly breaks it into smaller pieces and releases saliva, which starts the digestion process.
• Types of Teeth:
  • Incisors: Used to cut food.
  • Canines: Used to tear food.
  • Premolars: Used to crush food.
  • Molars: Used to grind food.
• Oral Hygiene: It is important to brush regularly and rinse the mouth after eating to prevent cavities (holes in teeth caused by bacteria).

Seasonal and Local Food

• Seasonal Fruits: Fruits like lychees, mangoes, and jamuns taste best and are most nutritious when eaten in their natural season.
• Local Food: Eating locally grown food is better as it is fresher and doesn't have to travel long distances.