Question

Acceptable limit of Total Volatile Base Nitrogen (TVB-N) in fish muscle is :

• A. 35-40 mg/100g
• B. 30-35mg/100g
• C. 25-30mg/100g
• D. 40-45mg/100g

Hint:

$30\text{ to }35\text{ mg N/100g}$ is the universally accepted chemical threshold for fish freshness. Any value above this range indicates microbial spoilage and decay.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
As fish spoil, bacterial and enzymatic action breaks down proteins and non-protein nitrogenous compounds, releasing volatile bases such as trimethylamine (TMA) and ammonia.
The concentration of these bases is measured as Total Volatile Base Nitrogen (TVB-N) and is used as an chemical indicator of fish freshness and spoilage.
Detailed Explanation:
TVB-N values increase as fish quality deteriorates:
- Very fresh fish: Typically contains less than $10\text{–}15\text{ mg TVB-N/100g}$ of muscle.
- Moderately fresh fish: Contains $15\text{–}25\text{ mg TVB-N/100g}$.
- Limit of acceptability: Most international food safety standards (including the European Union and FSSAI) set the critical limit for human consumption between $30\text{ and }35\text{ mg TVB-N per }100\text{g}$ of fish muscle, depending on the species group.
Values exceeding $35\text{ mg/100g}$ indicate that the fish is spoiled and unfit for human consumption.

Step 2: Final Answer:
The acceptable limit of TVB-N in fish muscle is 30-35mg/100g, corresponding to option (2).