Question

The causative organism for late blowing defect in canned milk products is

• A. Coliforms Species
• B. Clostridium Species
• C. Pseudomonas Species
• D. Bacillus Species

Hint:

Late blowing is caused by anaerobic spore-forming Clostridium spp. fermenting lactate into gas, whereas early blowing is caused by gas production from facultative anaerobic coliforms.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Late blowing is a preservation defect characterized by gas production, package swelling, and off-flavors that occur during extended storage of canned or vacuum-packaged dairy products.

Step 2: Detailed Explanation:
The "late blowing" defect is caused by anaerobic, spore-forming bacteria of the genus Clostridium (specifically Clostridium tyrobutyricum and Clostridium sporogenes).
These bacteria enter raw milk from silage or fecal contamination and survive heat processing as endospores.
During storage, the anaerobic environment within the can or package allows the spores to germinate.
These vegetative cells ferment lactic acid, producing butyric acid, carbon dioxide, and hydrogen gas:
\[ 2\,\text{Lactic Acid} \rightarrow 1\,\text{Butyric Acid} + 2\,\text{CO}_2 + 2\,\text{H}_2 \] The accumulation of these gases increases internal pressure, causing the package to swell or blow.
In contrast:
Coliforms cause "early blowing" defects within the first few days of manufacture because they are rapid lactose fermenters but are destroyed by pasteurization.
Pseudomonas species are heat-sensitive psychrotrophs that cause proteolysis but do not survive canning.
Bacillus species are aerobic spore-formers that typically cause sweet curdling or flat-sour spoilage rather than gas blowing.

Step 3: Final Answer:
Thus, Clostridium species are the causative organisms for the late blowing defect.