Foods can be preserved in many ways by slowing or preventing bacterial growth. Which of these methods should be least effective at inhibiting bacterial growth?
A) Refrigeration: slows bacterial metabolism and growth.
B) Closing previously opened containers: prevents more bacteria from entering, and excludes O₂.
C) Pickling: creates a pH at which most bacterial enzymes cannot function.
D) Canning in heavy sugar syrup: creates osmotic conditions that remove water from most bacterial cells.
E) Irradiation: kills bacteria by mutating their DNA to such an extent that their DNA-repair enzymes are overwhelmed.

Question

Quizplus · Accepted Answer

Closing previously opened containers does not directly inhibit the bacteria that are already inside the container; it mainly prevents new bacteria from entering. Other methods like refrigeration, pickling, canning in heavy syrup, and irradiation directly slow down or kill bacteria.

Foods Can Be Preserved in Many Ways by Slowing or Preventing