Cold Storage for Tomatoes: Why Chilling Injury Sets a Floor Under the Fridge Temperature

Tomatoes are one of the crops most often ruined by well-intentioned cold storage. The instinct is to treat them like any other vegetable and put them in the coldest room available. Do that and the tomatoes come out looking fine, then within a day or two of coming back to room temperature they turn pitted, watery, and never develop full colour or flavour. The cause is chilling injury, and it is why tomatoes sit in an awkward middle zone — they need cooling, but not the temperatures most cold rooms are set to.

Why tomatoes cannot be stored cold

Tomatoes evolved in a warm climate and, like bananas, cucumbers, aubergine and many tropical crops, they are chilling-sensitive. Below a threshold in the region of the low teens Celsius, the cell membranes of the fruit are damaged even though nothing freezes. The damage is not always visible at once — the fruit can look acceptable while still cold — but it shows up after the tomato is warmed again:

• Pitting — small sunken lesions on the skin.
• Water-soaked, mealy flesh that breaks down instead of staying firm.
• Failure to ripen — a chilled green or breaker tomato often never turns fully red, staying blotchy and pale.
• Loss of the aroma compounds that make a tomato taste of anything, so even a coloured fruit is flat.
• More decay, because the injured tissue is an easy entry for rot organisms.

The longer the fruit is held below the threshold, the worse the injury — a brief dip is survivable, a week is not.

The practical temperature floor

Because of chilling injury, tomatoes are generally held above about 12 to 13 degrees Celsius, warmer than almost anything else in a mixed cold store. The exact figure depends on ripeness:

• Mature green and breaker-stage tomatoes (picked hard, to ripen later) are the most chilling-sensitive and need the warmer end — around 12 to 15 degrees — which also lets them ripen slowly and evenly.
• Firm ripe (red) tomatoes tolerate slightly cooler holding for a short period — the low end of the teens — because they have less ripening left to lose, but they still should not go into a standard vegetable room.

This is the single most useful fact about storing tomatoes: the target is a cool room, not a cold one, and putting them in with leafy greens or root vegetables at a few degrees Celsius will damage them.

Humidity and air

Tomatoes need high relative humidity — in the region of 85 to 95 percent — or they lose water and go soft and wrinkled. A room that is too dry undoes the benefit of correct temperature. At the same time the air must move enough to carry away heat and keep the room uniform, and there must be fresh-air exchange or the carbon dioxide and ethylene build up. Which raises the next point.

Keep tomatoes away from ethylene — or use it deliberately

Ripe tomatoes give off ethylene, the ripening hormone. Stored next to ethylene-sensitive crops — leafy vegetables, cut flowers, immature produce — they will accelerate spoilage in those neighbours. And green tomatoes exposed to ethylene from other sources will start ripening whether you want them to or not. The two sensible approaches are: store tomatoes on their own, in their own room at their own temperature; or ripen mature-green tomatoes on purpose in a controlled ripening room with a measured ethylene dose and a set temperature, then move them out as they colour. What you should not do is store mixed produce and hope.

Handling before and after the store

• Cool gently and soon. Field heat should come off within hours of harvest, but down to the tomato’s safe holding temperature, not to a standard cold-room temperature.
• Grade out damage first. A split or bruised tomato in a crate seeds rot through the whole crate in a warm room.
• Do not stack deep. Tomatoes crush under their own weight; shallow crates, not sacks.
• Warm up gradually on the way to market to limit condensation, which invites decay.
• Move first-in stock first — even correctly stored tomatoes have a short window measured in a couple of weeks, not months.

What this means for your cold storage plan

If tomatoes are a significant part of what you handle, they need their own space held at their own temperature — you cannot serve them properly from a single general-purpose cold room shared with vegetables that want to be near freezing. That might mean a dedicated cool room, or a multi-room facility with independent temperature control, or a ripening room if you take fruit in green. The right configuration and its sizing depend on your volumes, your source stages and how fast you turn stock, so we scope tomato storage as part of a wider produce plan rather than as a standard box.

Related reading: cold storage for potatoes and vegetables, ethylene ripening chambers, humidity control in cold storage and pre-cooling fresh produce. See our services, contact DE International, our sourcing service and shop.