Question

Which among the following is an indicator of spoilage in shrimp ?

• A. Indole
• B. Cadaverine
• C. Histamine
• D. Putreseine

Hint:

Remember: Indole = Shrimp Quality. It correlates very well with sensory scores (smell/texture) and is used in export quality control to detect if shrimp were mishandled before freezing.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks for a specific chemical metabolite used as a marker to assess the degree of microbial spoilage in shrimp (prawns).
Detailed Explanation:

• Formation of Indole: Indole is produced by the action of bacteria (like Proteus, Escherichia) on the amino acid Tryptophan during the spoilage of shrimp.

• Specificity to Shrimp: While Biogenic Amines like Histamine and Cadaverine are also indicators of spoilage, Indole is the internationally recognized chemical index for assessing the quality of raw shrimp. The USFDA has established levels (e.g., 25 $\mu$g/100g) as the threshold for spoilage.

• Evaluation of other options:
• Histamine: Is a specific indicator for "Scombroid" fishes (Tuna, Mackerel).

• Cadaverine and Putrescine: Are general biogenic amines but are not the "primary" specific indicators cited for shrimp quality grading in industry.

Step 2: Final Answer:
Indole is the primary chemical indicator of spoilage in shrimp.