Question

Flat sour spoilage of canned food is due to the action of the following bacterium is

• A. Salmonella
• B. Clostridium botulinum
• C. Bacillus stearothermophilus
• D. Bacillus coagulans

Hint:

"Flat Sour" = Can ends remain flat + Contents have a sour taste.
It is caused by thermophilic facultative anaerobes that grow in warm storage, making proper warehouse cooling crucial.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Canned foods can undergo microbiological spoilage if the thermal sterilization process is insufficient or if post-process leakage occurs.

Step 2: Detailed Explanation:
"Flat sour" is a common type of spoilage in low-acid canned foods (such as fish products).
It is caused by thermophilic spore-forming bacteria, primarily {Bacillus stearothermophilus (now called Geobacillus stearothermophilus).
These bacteria survive inadequate heat processing, grow under warm storage conditions, and ferment carbohydrates to produce organic acids (which sours the food).
Because they do not produce gas during this fermentation, the can ends do not bulge and remain flat, making it difficult to detect visually before opening.

Step 3: Final Answer:
Flat sour spoilage is caused by Bacillus stearothermophilus, corresponding to option (C).