Can Defects Due to Under Processing

Common defects in cans due to under processing is/are:

Correct Answer: All the Above

The defects in cans due to under-processing (insufficient heat treatment) include Flipper, Springer, Soft Swell, and Hard Swell — collectively these represent different stages of gas accumulation from microbial activity in inadequately sterilized cans.

Classification of Can Defects by Severity

• Flipper — appears normal; one end slightly concave but 'flips' out when pressed. Earliest stage. No visible swelling yet.
• Springer — one end permanently bulged; the other end 'springs' out when pressed. Moderate gas production.
• Soft Swell — both ends bulge but the can sides can still be dented by finger pressure. Active microbial gas production.
• Hard Swell — both ends bulge rigidly; cannot be dented. Dangerous — can may burst. Maximum gas accumulation.

Cause of These Defects

• Surviving spore-forming bacteria (e.g., Clostridium botulinum) produce gas (CO₂, H₂) after inadequate heat treatment.
• Most important chemical spoilage = Hydrogen swell (not microbial — due to acid in product reacting with tin can).