Cold storage temperatures

Last updated October 21, 2026

“Cold storage” can mean a cool room for tomatoes or a freezer running far below zero for vaccines and biological samples. Words like chilled, frozen, deep-frozen and ultra-low aren’t standardized across industries, so two warehouses can use the same word for quite different set points. Below are the usual zones in Fahrenheit and Celsius, what goes in each, and the building features and quality systems that keep a room in range. Facility types in general are covered under storage types.

The main zones

The table mixes food-industry practice with the storage definitions WHO publishes for medical products. These are typical ranges, not legal limits. The product’s label, specification or customer contract comes first.

The pharma rows follow WHO’s recommended storage conditions, which put a refrigerator at 5 ± 3 °C, a freezer at -20 ± 5 °C and a deep freezer at -70 ± 10 °C. Product kept in liquid nitrogen vapor sits colder than any of these and usually goes to a specialist biorepository, not a general cold store.

What goes where

Produce is where “colder is better” goes wrong most often. University of Georgia Extension puts apples, berries, broccoli, carrots, lettuce and many other crops at 32 to 36 °F (0 to 2 °C). Cucumbers, eggplant, okra, peppers, summer squash and ripe tomatoes belong near 50 °F (10 °C), because anything colder gives them chilling injury. The same source lists apples, pears, cantaloupe, peaches and plums as high ethylene producers that shouldn’t share a room with ethylene-sensitive crops, even when the temperature suits both. A mixed produce room has to be split by ethylene behavior as well as by temperature.

Chilled dairy, meat and seafood rooms generally run at or below 40 °F (4 °C), the figure the FDA gives for refrigerators. Frozen storage is benchmarked at 0 °F (-18 °C). The FDA says food at that temperature is safe indefinitely, but quality keeps dropping the longer it’s held. So holding time still counts in a freezer, and first-expired, first-out rotation applies to frozen goods as well.

Ice cream usually sits colder than other frozen food, since partial thawing and refreezing coarsens the texture. Researchers at South Dakota State University describe -20 °F (-28.9 °C) as the industry standard for ice cream storage. If you store frozen desserts, check the room’s actual set point against the manufacturer’s specification. A room being classed as “frozen” doesn’t tell you that.

Most temperature-controlled medicines fall into two bands. Refrigerated means 2 to 8 °C (36 to 46 °F). For controlled room temperature WHO recommends 15 to 25 °C (59 to 77 °F), while the US Pharmacopeia has historically used 20 to 25 °C with excursions allowed between 15 and 30 °C. In 2026 USP proposed aligning its definition with 15 to 25 °C. Until the definitions converge, the label and the marketing authorization holder’s stability data decide what a warehouse can accept.

Blast freezers and holding freezers

A holding freezer keeps product that arrives already frozen at a steady temperature. Its refrigeration is sized for heat leaking in through walls, doors and people, not for warm pallets. A blast freezer or blast cell runs colder supply air at much higher velocity to pull heat out of product fast, and the product is spaced so air reaches every case.

Use a holding room to freeze warm product and the room temperature climbs, taking the stock around it along. Before you sign, ask whether the facility offers blast freezing, how much product it can freeze per day, how pallets are stacked during the freeze, and how the operator confirms core temperature has been reached before product moves to holding.

Buildings, humidity and docks

Plenty of modern cold stores put several zones under one roof: a chilled dock, chilled rooms, one or more freezers, and sometimes convertible rooms whose set point can be changed. Customers can consolidate inventory that way. The catch is the internal boundaries, where warm, moist air meets cold surfaces.

Two design points are worth checking. High-bay rooms are prone to stratification, and WHO mapping guidance notes that high-bay pallet racking stores are particularly susceptible and should be mapped over their full working height. Freezer floors on grade are normally built with insulation and an under-floor heating or ventilation system so the ground beneath doesn’t freeze and heave. Ask about that when a building has been converted from another use.

Humidity is the other half of the storage condition. The UGA guidance gives 90 to 95% relative humidity as ideal for most fruits and vegetables, but 65 to 75% for onions and garlic. For medicines, WHO equates “store in a dry place” with no more than 60% relative humidity. A site handling both produce and pharma needs separate humidity control, not only separate rooms.

Doors and docks are where most temperature and humidity trouble starts. Every opening lets in warm, moist air, which ends up as frost on coils, floors and packaging. Insulated high-speed doors between zones help, often with air curtains or strip curtains behind them. Freezers should have a vestibule or anteroom in front so two doors are never open at once, and refrigerated docks need seals or shelters that close around the trailer. WHO recommends separate receiving and dispatch areas where possible to avoid mix-ups. It also expects temperature-controlled goods to be handled first at receiving, with the transport temperature data reviewed before the product is accepted.

Monitoring and alarms

WHO’s storage guidance says temperature, and humidity where relevant, should be controlled and monitored at regular intervals with calibrated equipment, then recorded and reviewed, with records kept as national law requires. A well-run cold store does this with continuous electronic monitoring and puts sensors at the hot and cold spots found during mapping, not next to the thermostat.

Questions to put to a site:

1. What are the alarm set points, and how do they relate to the product specification? An alarm that only fires at the product limit leaves no time to react.
2. Who gets alarms outside working hours, and what is the documented response time?
3. Is there backup refrigeration or generator power, and has the room been tested for how long it holds temperature after a power loss?
4. How long are monitoring records kept, and can the customer get a copy of any excursion report?
5. When were the sensors last calibrated, and by whom?

The facility checklist goes into these and other site questions.

Temperature mapping

A mapping study logs temperature at many points across a room to find out how it really behaves. WHO’s technical supplement on mapping sets out a widely used method. A new room is mapped before commissioning, both empty and loaded. It’s mapped again after significant changes such as a new set point, altered airflow or heavier loading, and periodically after that; WHO gives every three years as an example. Ambient warehouses that swing with the seasons may need one study in the warmest season and one in the coldest. Cold and freezer rooms typically don’t.

Ambient studies run for at least seven consecutive days, including a weekend. Cold rooms and freezer rooms need 24 to 72 hours. Data loggers go in a grid every 5 to 10 meters (about 16 to 33 feet), stacked at low, middle and high levels, and each one has to be calibrated to an error of no more than ±0.5 °C. If door openings are part of the test, temperatures should be back within limits no more than 30 minutes after the door is opened.

The report shows hot and cold spots, zones where sensitive product shouldn’t be stored, and the best spots for permanent monitoring sensors. Anyone storing regulated or high-value product should ask for the latest mapping report on the specific rooms they’ll be using. Temperature excursion, temperature mapping and blast freezing are defined in the glossary, and the directory lists cold storage providers by region.

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