What freezing temperature range stops growth of microorganisms?

• A. -20 to 0°F
• B. -4 to 10°F
• C. 0 to 32°F
• D. -40 to -10°F

Answer: (A)

Freezing stops the growth of microorganisms because water inside and around cells turns to ice, which slows or halts metabolic processes and makes nutrients unavailable for replication. When temperatures are in the range roughly from -20°F up to 0°F (-29°C to -18°C), most bacteria, yeasts, and molds cannot multiply, so growth is effectively halted during storage. In practice, this is the standard freezer range used to prevent microbial growth in foods.

The other ranges either approach or exceed the freezing threshold in ways that don’t reliably prevent growth under typical conditions, or involve temperatures that are not the standard freezing storage for preventing microbial multiplication.