Question

Struvite formation in canned fish can be prevented by the addition of

• A. Magnesium ammonium phosphate
• B. Sodium benzoate
• C. Ethylene diamine tetra acetate
• D. Sodium chloride

Hint:

Struvite crystals are often mistaken for glass but can be distinguished because they dissolve in vinegar (acid). Adding chelating agents like EDTA or acidifying the medium (e.g., adding citric acid) are common prevention methods.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question focuses on a common defect in canned seafood known as "Struvite" and how to prevent it. Struvite crystals resemble glass shards and can cause consumer complaints, although they are harmless.
Detailed Explanation:

• What is Struvite? Struvite is a crystal formed of Magnesium Ammonium Phosphate hexahydrate ($MgNH_4PO_4 \cdot 6H_2O$). These crystals form slowly after the canning process, especially in marine species like tuna, salmon, and shrimp, which are rich in magnesium and phosphates.

• Prevention using Chelating Agents: To prevent these crystals from precipitating, the magnesium ions ($Mg^{2+}$) must be sequestered or bound so they cannot react with ammonia and phosphate.

• EDTA (Ethylene Diamine Tetra Acetate): EDTA is a powerful chelating agent (sequestrant). When added to the canning brine or medium, it binds with the magnesium ions, preventing the formation of struvite crystals.

• Evaluation of Options:
• Option (A): Is the chemical name of Struvite itself.

• Option (B) and (D): Sodium benzoate is a preservative, and Sodium chloride is common salt; neither prevents crystal formation.

Step 2: Final Answer:
Struvite formation is prevented by adding EDTA.