Salt: Food Preservative

The video explains how microorganisms thrive in the water content of food, which can be up to 50% in items like tomatoes. To preserve food, water content must be reduced to inhibit bacterial growth. The Egyptians discovered that salt, found in sand, was effective in preserving bodies and later food. Salt, mainly sodium chloride, works by drawing water out of bacterial cells through osmosis, preventing their growth. This method requires reducing food's water content to about 0.91%. Salt has been used for preservation throughout history and remains a key method today.

What is one of the main reasons microorganisms thrive in food?

• Presence of water

• Exposure to air

• Lack of refrigeration

• High sugar content

How did the Egyptians discover the preservative properties of salt?

• By observing the slow decay of bodies buried in sand

• By using salt in cooking

• Through trial and error with food storage

• By experimenting with different spices

What is the primary component of salt that helps in food preservation?

• Sodium chloride

• Potassium chloride

• Calcium carbonate

• Magnesium sulfate

What process describes the movement of water out of bacterial cells due to salt?

• Evaporation

• Osmosis

• Diffusion

• Condensation

To what percentage must the water content in food be reduced to inhibit bacterial growth?

• 10%

• 0.91%

• 5%

• 1.5%