Step 1: Understanding the Concept:
Canned dairy products undergo commercial sterilization designed to destroy all vegetative cells and heat-resistant bacterial spores.
If spoilage occurs during subsequent storage, identifying the causative organism helps determine the root cause of the failure.
Step 2: Detailed Explanation:
Let us analyze why the presence of non-sporeforming organisms indicates container leakage:
- Heat sterilization easily destroys all vegetative cells and non-sporeforming organisms (such as coliforms, yeasts, molds, and non-thermoduric micrococci).
- If these non-sporeforming organisms are found growing in the spoiled can, they could not have survived the sterilization process.
- Therefore, they must have entered the can after processing.
- This occurs when micro-leaks are present in the double seams or seal of the can.
- During the cooling phase, the hot can is sprayed with water, which creates a vacuum inside the can as it cools.
- If there is a micro-leak, this vacuum draws contaminated cooling water into the can.
- The introduced non-sporeforming bacteria then multiply in the milk, causing rapid spoilage.
- This form of contamination is known as "leaker spoilage," and the compromised container is called a leaker.
- In contrast, if spoilage is caused by highly heat-resistant spores, it represents under-processing rather than container leakage.
Step 3: Final Answer:
When non-sporeforming organisms cause spoilage in sterilized canned milk, the compromised container is called a leaker.