Which bacteria form spores that can survive pasteurization?

Which bacteria form spores that can survive pasteurization?

• A. Listeria monocytogenes
• B. Staphylococcus aureus
• C. Spore-forming Bacillus species (e.g., Bacillus cereus)
• D. Escherichia coli

Answer: (C)

The key idea is that endospores provide true heat resistance. Some bacteria, especially Bacillus and Clostridium species, form spores when conditions aren’t favorable. These spores can survive pasteurization because the heat targets mainly vegetative cells, not spores. Bacillus cereus is a classic example: it forms spores that can endure pasteurization and later germinate if conditions allow, potentially causing spoilage or illness. The other organisms listed do not produce spores. Listeria monocytogenes, Staphylococcus aureus, and Escherichia coli are non-spore-forming, so pasteurization is designed to inactivate them as part of the process.

The key idea is that endospores provide true heat resistance. Some bacteria, especially Bacillus and Clostridium species, form spores when conditions aren’t favorable. These spores can survive pasteurization because the heat targets mainly vegetative cells, not spores. Bacillus cereus is a classic example: it forms spores that can endure pasteurization and later germinate if conditions allow, potentially causing spoilage or illness.

The other organisms listed do not produce spores. Listeria monocytogenes, Staphylococcus aureus, and Escherichia coli are non-spore-forming, so pasteurization is designed to inactivate them as part of the process.