Which of the following cannot be used as a food preservative ?

Options

A. Sodium metabisulphite
B. Sodium hydroxide
C. Sodium benzoate
D. Citric acid

Answer

To determine which of the following cannot be used as a food preservative, we need to analyze the options provided. Here’s a step-by-step solution:

### Step 1: Understand the Role of Food Preservatives
Food preservatives are substances added to food to prevent spoilage caused by microorganisms (like bacteria and fungi) and to prolong shelf life. Common types of food preservatives include salts, sugars, acids, and certain chemical compounds.

### Step 2: Analyze the Given Options
Let's consider the options mentioned in the video transcript:
1. Sodium Hydroxide
2. Sodium Benzoate
3. Salt (Sodium Chloride)
4. Citric Acid

### Step 3: Evaluate Each Option
- **Sodium Hydroxide**: This is a strong base and is not typically used as a food preservative.
- **Sodium Benzoate**: This is a common food preservative that prevents the growth of bacteria, yeast, and fungi.
- **Salt (Sodium Chloride)**: Salt is widely used as a preservative due to its ability to draw moisture out of food, inhibiting microbial growth.
- **Citric Acid**: This is an organic acid that can create an acidic environment, which is not conducive to the growth of many microorganisms, making it a common preservative.

### Step 4: Identify the Incorrect Option
From the analysis, we see that:
- Sodium Hydroxide is not used as a food preservative.
- Sodium Benzoate, Salt, and Citric Acid are all used as preservatives.

### Conclusion
The option that cannot be used as a food preservative is **Sodium Hydroxide**.

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