Canned dairy defects (milk, cream, evaporated milk): Which organisms commonly cause bitterness, acidity, and curdling?

Introduction / Context:Canned dairy products are low-acid and protein-rich, making them vulnerable, if underprocessed or contaminated, to sporeformers that survive heat. These organisms can generate acid, proteolysis, gas, and texture defects including curdling.

Given Data / Assumptions:

• Dairy matrix: milk/cream/evaporated milk.
• Candidates: Bacillus and Clostridium species.
• Observed defects: bitterness, acidity, curdling.

Concept / Approach:Bacillus (aerobic/facultative sporeformers) and Clostridium (anaerobic sporeformers) both produce heat-resistant spores and enzymes. Proteases can yield bitter peptides; acid production and gas can destabilize casein micelles, causing clotting/curdling. Thus, both genera are implicated in these canonical dairy can defects.

Step-by-Step Solution:Recognize dairy can environment and survival of spores.Map defects (bitter, acid, curdling) to enzymatic and fermentative activities.Select the combined option including both genera.

Verification / Alternative check:Thermal process schedules for dairy aim at worst-case sporeformers from both groups to prevent these failures.

Why Other Options Are Wrong:

• Saccharomyces / Pseudomonas only: Yeasts are less typical in hermetic cans; Pseudomonas are heat-labile and rarely survive retorting.

Common Pitfalls:Assuming one genus explains all defects; mixed sporeformer ecology is common in plant environments.

Final Answer:Both (a) and (b).