The danger zone
Between 4°C (40°F) and 60°C (140°F), bacteria multiply fast. Some can double in about 20 minutes. Cold food belongs below that range and hot food above it. Food gets 2 hours total in the range, or 1 hour if the room is above 32°C (90°F).
Keep cold food cold and hot food hot
Keep the fridge at 4°C (40°F) or colder and the freezer at -18°C (0°F). Keep hot food at 60°C (140°F) or above. Cold slows bacteria, and hot holding stops them. A cheap fridge thermometer tells you the truth.
Test yourself
Questions from the interactive lesson, with the answer and the why.
You left cooked pasta on the counter after dinner. When is the latest to refrigerate it?
Within 2 hours of coming off the heat. Two hours is the standard limit for food between 4°C and 60°C.
True or false: Bacteria multiply rapidly between 4°C (40°F) and 60°C (140°F).
True. Cold slows growth below 4°C and heat stops it above 60°C, but in between some bacteria double in about 20 minutes.
What went wrong? You leave a pot of chili on the counter from 6 pm to 11 pm, then refrigerate it. Tomorrow you reheat it and serve it.
It sat between 4°C and 60°C well past 2 hours. Hours in the danger zone let bacteria grow, and reheating may not undo that.
Fill the blank: The danger zone runs from 4°C (40°F) up to ___.
The danger zone runs from 4°C (40°F) up to 60°C (140°F). Above 60°C, hot holding keeps bacteria from growing.
Your fridge should be at or below what temperature?
About 4 C. A fridge should sit at 4°C (40°F) or colder.
A picnic hits 35°C (95°F). How long can the potato salad sit out?
Up to 1 hour. Above 32°C (90°F), the safe window shrinks to 1 hour.