Question

Anaerobic spoilage in canned foods with cheese odour and pronounced blowing but without $H_2S$ production is caused by __________.

• A. Thermoanaerobacterium thermosaccharolyticum
• B. Streptococcus thermophilus
• C. Bacillus coagulans
• D. Bacillus polymyxa

Hint:

Remember: Swollen Can + Cheesy Odor + No Blackening = T. thermosaccharolyticum. If the can was flat but sour, it would be B. coagulans. If it was black and smelled like rotten eggs, it would be Desulfotomaculum.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question relates to the microbiology of canned food spoilage. It describes a specific set of spoilage characteristics: anaerobic conditions, production of gas leading to "blowing" (swelling) of the can, a distinct cheese-like odor, and the absence of hydrogen sulfide ($H_2S$).

Step 2: Detailed Explanation:

• Canned Food Spoilage Categories: Canned food spoilage is generally classified into "Flat Sour," "Thermophilic Anaerobic (TA)," and "Sulfide Stinker."

• TA Spoilage Characteristics: Thermophilic Anaerobic (TA) spoilage is caused by saccharolytic, non-sulfide producing anaerobes. These organisms ferment sugars to produce acids and significant amounts of $CO_2$ and $H_2$ gas. This gas pressure causes the cans to swell or "blow."

• Causative Agent: Thermoanaerobacterium thermosaccharolyticum is the classic causative agent for this type of spoilage. It is an obligate thermophile that produces a characteristic "cheesy" or butyric acid odor due to its metabolic byproducts.

• Distinction from others:
- Sulfide spoilage (e.g., Desulfotomaculum nigrificans) produces $H_2S$ which turns the can black.
- Flat sour spoilage (e.g., Bacillus coagulans) produces acid but NO gas, so the can does not swell.
- {Bacillus polymyxa is a facultative anaerobe that causes gas in low-acid foods but is not the primary thermophilic agent described with cheesy odors in TA spoilage.

Step 3: Final Answer:
The description of gaseous blowing with a cheesy odor and no $H_2S$ is characteristic of Thermoanaerobacterium thermosaccharolyticum.