Which of the following pairs correctly describe two common food preservation methods and their basic mechanism?

• A. Refrigeration slows bacteria growth by lowering temperature; Canning uses heat to kill bacteria
• B. Freezing dries out bacteria
• C. Fermentation uses heat to kill all bacteria
• D. Dehydration adds moisture to food to preserve it

Answer: (A)

The fundamental idea here is that food preservation often hinges on controlling microbial growth by changing temperature and exposure to heat. Refrigeration slows bacteria and mold by lowering the temperature, which reduces their metabolic rate and their ability to reproduce, so food stays safe longer without necessarily being killed. Canning preserves by applying heat strong enough to destroy microorganisms and their spores, then sealing the container so no new microbes can enter; that combination of heat treatment and a sealed package is what keeps the food stable at room temperature.

The other statements don’t match how these methods work. Freezing slows activity but doesn’t dry out bacteria; it preserves by freezing water and halting most growth, not by dehydration. Fermentation isn’t about heating to kill all bacteria; it relies on specific microbes producing acids or alcohol to inhibit spoilage and preserve food, often without sterilizing every organism present. Dehydration preserves by removing moisture, not adding it.