Without oil, air would reach the pickle, allowing microbes to grow. This would spoil the pickle quickly, making it unsafe to eat and changing its smell, taste and colour.
Class 5 Environmental Studies Grade 5 Chapter 3 The Mystery of Food solutions
CBSE Class 5 EVS Unit 2: Health and Well-being Chapter 3 The Mystery of Food Question Answer
If no oil is added, air can enter the pickle jar, giving microbes the oxygen they need to grow. This would cause the pickle to spoil quickly, develop a foul smell, lose its flavour and become unsafe to eat. The protective oil layer is essential for long-term preservation of pickles.
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