What is the Ideal Temperature Setting for Refrigerators?
Grade Level: 6th-9th; Type: Microbiology
Discover how temperature settings affect bacterial growth.
- What temperature inhibits bacterial growth? Does this vary for different food items?
- What happens to the human body when bacterial-contaminated food is consumed?
Before refrigerators and freezers were invented, people cooled their food and kept them from spoiling by putting it in ice and snow. This was obvious not convenient and does not nearly have the same power as a mechanic refrigerator/ freezer does.
- Three refrigerators (the compact ones are more economical for this experiment)
- Three bunches of celery, three packages of sausage, three containers of milk
- Turn one fridge to the lowest temperature setting (usually this is the number 1); the second to medium (this is usually the number 5); and the thirdfridge to the highest setting (this is usually a 9).
- Place identical food items in each fridge. Close the fridges.
- Wait 30 minutes and then take and record the peak temperature of each fridge with a thermometer.
- Every day for at least two weeks, remove samples from each food item and observe their bacterial formations with a microscope.
- At the end of two weeks, evaluate which refrigerator fared best at keeping the food in optimal, consumable condition.
Terms/Concepts: Refrigeration; Bacteria; Food safety; Temperature
- Who invented the refrigerator?
- What did people use before refrigerators?
- The Basics of Chemistry, by Richard Myers (Greenwood Publishing Group, 2003)
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