Question:
Bloats in evaporated milk is caused by
Bloats in evaporated milk is caused by
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Remember:
- Swelling/Bloating of cans with foul odors \(\rightarrow\) Caused by gas-producing anaerobic sporeformers like Clostridium foetidum.
- Coagulation or thinning without gas \(\rightarrow\) Caused by aerobic sporeformers like Bacillus subtilis.
- Swelling/Bloating of cans with foul odors \(\rightarrow\) Caused by gas-producing anaerobic sporeformers like Clostridium foetidum.
- Coagulation or thinning without gas \(\rightarrow\) Caused by aerobic sporeformers like Bacillus subtilis.
Updated On: Jul 23, 2026
- Proteus ichthyosmius
- Staphylococcus epidermides
- Bacillus subtilis
- Clostridium foetidum
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The Correct Option is D
Solution and Explanation
Step 1: Understanding the Concept:
Evaporated milk is preserved by thermal sterilization inside sealed cans.
If any anaerobic, spore-forming bacteria survive this heat treatment, they can grow and multiply under the anaerobic conditions inside the can, causing severe gas-producing spoilage.
Step 2: Detailed Explanation:
The "bloats" or "blown cans" defect refers to the severe swelling of the can't ends due to high internal gas pressure:
- Mechanism of Spoilage:
The swelling is caused by the metabolic activity of gas-producing anaerobic sporeformers belonging to the genus Clostridium.
- Causative Agent:
Clostridium foetidum is a highly active anaerobic sporeformer that can survive standard sterilization temperatures.
It is both proteolytic and saccharolytic.
During growth in evaporated milk, it ferments lactose and proteins, producing large volumes of carbon dioxide (\(\text{CO}_2\)) and hydrogen (\(\text{H}_2\)) gas.
This rapid gas production increases the internal pressure, causing the flat ends of the can to bulge outward (bloat).
- Associated Changes:
This bacterial growth also causes severe protein putrefaction, releasing volatile sulfur compounds that impart a highly offensive, foul odor to the milk.
- Let us compare this with the other options:
- Proteus ichthyosmius produces a fishy off-flavor but is non-sporeforming.
- Bacillus subtilis is an aerobic sporeformer that typically causes sweet curdling or thinning without gas production.
Therefore, the anaerobic sporeformer Clostridium foetidum is the primary cause of bloating.
Step 3: Final Answer:
Bloating (gas-induced swelling of cans) in evaporated milk is caused by the anaerobic sporeformer Clostridium foetidum.
Evaporated milk is preserved by thermal sterilization inside sealed cans.
If any anaerobic, spore-forming bacteria survive this heat treatment, they can grow and multiply under the anaerobic conditions inside the can, causing severe gas-producing spoilage.
Step 2: Detailed Explanation:
The "bloats" or "blown cans" defect refers to the severe swelling of the can't ends due to high internal gas pressure:
- Mechanism of Spoilage:
The swelling is caused by the metabolic activity of gas-producing anaerobic sporeformers belonging to the genus Clostridium.
- Causative Agent:
Clostridium foetidum is a highly active anaerobic sporeformer that can survive standard sterilization temperatures.
It is both proteolytic and saccharolytic.
During growth in evaporated milk, it ferments lactose and proteins, producing large volumes of carbon dioxide (\(\text{CO}_2\)) and hydrogen (\(\text{H}_2\)) gas.
This rapid gas production increases the internal pressure, causing the flat ends of the can to bulge outward (bloat).
- Associated Changes:
This bacterial growth also causes severe protein putrefaction, releasing volatile sulfur compounds that impart a highly offensive, foul odor to the milk.
- Let us compare this with the other options:
- Proteus ichthyosmius produces a fishy off-flavor but is non-sporeforming.
- Bacillus subtilis is an aerobic sporeformer that typically causes sweet curdling or thinning without gas production.
Therefore, the anaerobic sporeformer Clostridium foetidum is the primary cause of bloating.
Step 3: Final Answer:
Bloating (gas-induced swelling of cans) in evaporated milk is caused by the anaerobic sporeformer Clostridium foetidum.
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