Canned acidic fruits (pineapple, tomatoes, pears): Spoilage by Clostridium pasteurianum is more likely when product pH is…

Microbiology Heated Canned Foods Difficulty: Easy
Choose an option
  • A
    >4.5
  • B
    <4.5
  • C
    >5.3
  • D
    <5.3
  • E
    Exactly 3.7

Answer

Correct Answer: >4.5

Explanation

Introduction / Context:Product pH strongly dictates which sporeformers can outgrow in canned foods. Clostridium pasteurianum is an acid-tolerant, saccharolytic anaerobe that can spoil acidic fruits if pH control and processing are inadequate.

Given Data / Assumptions:

  • Foods: pineapple, tomatoes, pears (acid foods).
  • Organism: C. pasteurianum.
  • Question: which pH range favors its spoilage potential?

Concept / Approach:Most proteolytic clostridia cannot grow at pH below about 4.6. C. pasteurianum tolerates acid better than many clostridia, but risk rises as pH increases toward and above ~4.5. Hence, fruit products with pH > 4.5 are more susceptible to clostridial spoilage unless additional hurdles (heat, preservatives) are applied.

Step-by-Step Solution:Relate clostridial growth limits to pH boundaries.Identify threshold near 4.5–4.6 as critical for safety/spoilage control.Select “> 4.5” as the condition increasing spoilage likelihood.

Verification / Alternative check:Acidified foods target equilibrium pH ≤ 4.6 precisely to prevent clostridial growth; values above this threshold invite risk.

Why Other Options Are Wrong:

  • <4.5 or <5.3: Lower pH reduces clostridial growth potential.
  • >5.3: Although permissive, the key control point asked in practice is just above ~4.5 for acidic fruits.

Common Pitfalls:Ignoring pH drift after processing; formulation must ensure final equilibrium pH remains safely low.

Final Answer:>4.5.

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