Proteolytic (putrefactive) can spoilage indicators: Which Clostridium species produce H2S, mercaptans, ammonia, indole, and skatole from proteins?

Introduction / Context:
In canned protein foods, proteolytic (putrefactive) Clostridia are key spoilers. They degrade proteins and amino acids, releasing intensely odorous compounds such as hydrogen sulfide, mercaptans, ammonia, indole, and skatole, often with gas and darkening.

Given Data / Assumptions:

• Focus on protein decomposition and malodors.
• Species listed include C. sporogenes and C. putrefaciens, both classically proteolytic.
• Comparison against saccharolytic butyric species.

Concept / Approach:
Putrefactive species hydrolyze proteins (proteases) then deaminate/decarboxylate amino acids to volatile sulfur- and nitrogen-containing compounds. C. sporogenes is widely used as a non-toxic surrogate for proteolytic C. botulinum in process studies. C. putrefaciens is similarly proteolytic. In contrast, C. butyricum is more saccharolytic, producing butyric acid from carbohydrates rather than intense proteolysis.

Step-by-Step Solution:
Identify which species are proteolytic.Relate proteolysis to odorous end products (H2S, indole, skatole).Select the option including both proteolytic species.

Verification / Alternative check:
Spoilage compendia for canned meats consistently pair these odorants with proteolytic clostridial growth.

Why Other Options Are Wrong:

• C. butyricum / C. acetobutylicum: Primarily ferment carbohydrates to acids/solvents; not the hallmark putrefactive profile.

Common Pitfalls:
Confusing any gas with saccharolytic fermentation; odor character is a critical diagnostic cue.

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