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Food Spoilage and Preservation - Understanding Food Labels and Expiry

Grade 5CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

Food Spoilage is the process where food becomes unfit for consumption due to the growth of MicroorganismsMicroorganisms like BacteriaBacteria and FungiFungi.

Signs of spoilage include change in color, foul smell (odor), change in texture, and sour taste due to the production of AcidsAcids or GasesGases.

Food Preservation is the technique used to stop or slow down spoilage. Common methods include Boiling, Freezing (at 0C0^{\circ} C or below), Dehydration (removing H2OH_2O), and Adding Preservatives like Salt (NaClNaCl) or Sugar.

Understanding Food Labels is critical: The Mfg.DateMfg. Date (Manufacturing Date) tells us when the food was packed, and the Exp.DateExp. Date (Expiry Date) tells us the date after which the food is unsafe to eat.

The 'Best Before' label indicates the period during which the food maintains its peak quality, whereas the ExpiryExpiry date is a strict safety deadline.

Temperature plays a vital role: Most BacteriaBacteria grow rapidly between 5C5^{\circ} C and 60C60^{\circ} C, often referred to as the 'Danger Zone'.

📐Formulae

Shelf Life=Expiry DateManufacturing DateShelf\ Life = Expiry\ Date - Manufacturing\ Date

Rate of SpoilageTemperature×MoistureRate\ of\ Spoilage \propto Temperature \times Moisture

Boiling Point of Water=100CBoiling\ Point\ of\ Water = 100^{\circ} C

Freezing Point of Water=0CFreezing\ Point\ of\ Water = 0^{\circ} C

💡Examples

Problem 1:

A juice carton shows a Manufacturing Date of 10thJanuary202310^{th} January 2023 and states 'Best before 6 months from manufacture'. Calculate the approximate Expiry Date.

Solution:

10thJuly202310^{th} July 2023

Explanation:

Since the shelf life is 66 months, we add 66 months to the manufacturing month (January). January is month 11, so 1+6=71 + 6 = 7 (July).

Problem 2:

Why is salt (NaClNaCl) used to preserve pickles and fish?

Solution:

Salt removes moisture (H2OH_2O) through a process called OsmosisOsmosis.

Explanation:

By removing the water content, salt creates an environment where MicroorganismsMicroorganisms cannot survive or multiply, thus preventing spoilage.

Problem 3:

If a milk packet is kept at 35C35^{\circ} C and another is kept at 4C4^{\circ} C (refrigerator), which one will spoil first?

Solution:

The milk kept at 35C35^{\circ} C will spoil first.

Explanation:

High temperatures (35C35^{\circ} C) promote the rapid growth and reproduction of BacteriaBacteria, whereas low temperatures (4C4^{\circ} C) inhibit microbial activity.