Two numbers cover most of the temperature question in a home kitchen: keep the refrigerator at or below 4 °C and the freezer at or below −18 °C. The rest is about making sure those numbers are real, not just the setting on a dial.
The two reference temperatures
Canadian food safety guidance points to a refrigerator running at or below 4 °C and a freezer at or below −18 °C. These are the targets to verify, not aspirational settings. A dial marked “3” or “cold” does not tell you the actual air temperature inside.
| Compartment | Target | What it means |
|---|---|---|
| Refrigerator | 4 °C or below | Slows the growth of most bacteria that spoil food. |
| Freezer | −18 °C or below | Holds food frozen solid; quality is preserved over time. |
Where cold air actually sits
A refrigerator is not one even temperature. Cold air is denser and tends to pool low and toward the back, while the door is the warmest zone because it is exposed to room air every time it opens. That has practical consequences for where things go.
- Back and lower shelves: the coldest, steadiest zone — suited to raw meat, poultry and fish kept on a plate or in a container to catch drips.
- Upper shelves: slightly milder and more stable — leftovers, cooked food and ready-to-eat items.
- Crisper drawers: higher humidity for vegetables and fruit kept separately.
- The door: the warmest spot, best for condiments rather than milk or eggs.
Drips travel down. Storing raw meat below ready-to-eat food, not above it, keeps any leakage from reaching food that will not be cooked again.
Verify with a thermometer
An inexpensive appliance thermometer removes the guesswork. Place it in a glass of water in the middle of the fridge, leave it overnight, and read it before opening the door in the morning. The water mass dampens the swings caused by the compressor cycling and by door openings, giving a reading closer to the food's actual temperature.
After a power interruption
A closed freezer holds its temperature for a time even without power; a refrigerator loses cold far faster. When the exact safe window is uncertain, the official Canadian guidance is the right reference rather than a guess, because the answer depends on how full the appliance is and how long the door stayed shut.
For specific time limits after an outage, follow the current advice from Health Canada and the Canadian Food Inspection Agency.
Where this connects
Temperature is only half of the picture. Knowing how long something has been stored depends on a habit of labeling and dating, and keeping the coldest zones usable depends on a sensible layout across the kitchen.