Food Safety

Food Safety Basics: Temperatures, Freezing & Date Labels

The Food Safety Playbook: Temperature, Time and Labels

Most food goes bad for three reasons: it gets too warm, it stays out too long, or nobody is sure what the date on the label means. This section collects the guides that explain the why behind food storage, from the Danger Zone to freezer myths and date labels, so every other tip on this site makes sense.

Browse 8 guides Food storage chart

On this page: The Three Numbers That Keep Food SafeWhat the Dates on Your Food Really MeanJump Directly to the Food Safety Guides

Food containers in a refrigerator labeled with their contents and the date they were stored
A date on the lid is the easiest food safety habit.

Food safety is not about fear, it is about a few simple numbers. Once you know them, you waste less food and worry less about what is in the fridge. Everything in this section is grounded in the guidance of the USDA Food Safety and Inspection Service and the FDA.

The Three Numbers That Keep Food Safe

40°F (4°C): the FDA advises keeping your refrigerator at or below this temperature, and an appliance thermometer is the only way to know it does. 0°F (-18°C): the freezer temperature at which, according to the USDA, food will always be safe; only the quality drops over time. 2 hours: the longest perishable food may stay out of the fridge, or just 1 hour when it is hotter than 90°F (32°C). Between 40°F and 140°F, the Danger Zone, bacteria can double in as little as 20 minutes.

Freezing pauses bacteria, it does not kill them: the USDA explains that microbes become inactive at 0°F and can become active again after thawing. We explain what that means for your food in what happens to food when you freeze it and does freezing kill bacteria.

What the Dates on Your Food Really Mean

Except for infant formula, the USDA says date labels are not an indicator of safety. A “Best if Used By” date tells you when the product has its best flavor or quality, a “Sell-By” date is for the store, and a “Use-By” date is the last date for peak quality. The USDA estimates that 30 percent of food waste comes from people throwing away good food because they misread these dates. Read the full explanation in the truth about best before and use by dates.

8 guides

Marleen’s advice: food safety

Explore the food safety guides below. Each one explains one part of the science behind fresh food, in plain language.

Food Safety at a Glance

The rules that come back in every guide on this site, from the USDA and the FDA.

Temperatures to Remember

WhatTemperature
Refrigerator40°F (4°C) or below
Freezer0°F (-18°C)
Danger Zone40°F to 140°F
Food out of the fridge2 hours max
Above 90°F (32°C)1 hour max

When Mold Appears

The USDA advice depends on how firm and moist the food is:

  • Can be saved: hard cheese and firm foods. Cut off at least 1 inch around and below the mold spot.
  • Discard: soft, moist foods such as bread and baked goods, soft cheese, yogurt, sour cream, jam and soft fruit. Mold can spread below the surface. More in why food gets moldy faster in summer.

The Mistakes That Cost the Most Food

A fridge that runs too warm, food left out after dinner, and good food thrown away because of a misunderstood date are the everyday habits behind most spoiled groceries. Start with the biggest food storage mistakes and foods that should never go in the fridge, then use the food storage chart for the exact times of 50+ foods.