In a supermarket, a cold store or a refrigerated truck, low temperature can look passive. In reality, energy is continually used to hold food at the right temperature, monitor equipment and prevent breaks between each stage. Cooling extends shelf life and reduces losses, but it has an environmental footprint of its own.

On 17 August 2026, INRAE brought this trade-off into focus through new coverage of its FRISE research unit, which studies refrigeration engineering for food safety and the environment. One figure stands out: for frozen products, raising the storage temperature by 1°C could reduce cold-chain energy consumption by about 3%. This does not mean households should change their freezers today. It is a research estimate examined through the STEP project, which brings stakeholders together to assess the quality of frozen foods at different temperatures.

The useful question is broader than a thermostat setting: how can we use just enough cooling, in the right place and at the right time, without increasing food-safety risks or creating more waste?

What is the food cold chain?

The cold chain is the series of temperature-controlled steps that preserves food from production to consumption. It may begin within hours of harvest, when fruit or vegetables are pre-cooled. It then continues through processing sites, warehouses, trucks, logistics hubs, shops and restaurants, before ending in household refrigerators and freezers.

There is no single cold chain for every product. Fresh fish, yoghurt, ready-to-eat salad and frozen meals have different risks, temperatures and storage periods. Regulation, manufacturer instructions and product-specific risk assessments determine the conditions that apply.

Cooling does not sterilise food. It mainly slows chemical reactions and the growth of many microorganisms. Some hazards remain, and bacteria including Listeria monocytogenes can still grow at refrigeration temperatures. Temperature control therefore works alongside hygiene, use-by dates and safe handling; it does not replace them.

Why are quick-frozen foods kept at −18°C?

Under European Union rules, “quick-frozen” has a precise meaning. Food must pass quickly through the zone of maximum crystallisation and, after thermal stabilisation, be held at −18°C or colder. EU rules allow brief upward fluctuations of no more than 3°C during transport, local distribution and in certain retail display cabinets.

The −18°C baseline protects stability over time. As temperature rises, some physical and chemical changes accelerate: ice crystals can grow, textures can deteriorate, fats can oxidise, and flavour or vitamin quality can change depending on the product. Peas, ice cream, fish and prepared meals do not respond in exactly the same way.

The STEP project is not proposing an immediate, uniform increase. It is first taking stock of available evidence on the quality of different frozen products at different temperatures. Any future change would need to consider the full storage period, real temperature fluctuations, food categories, equipment and safety margins. A theoretical energy saving must be tested against the risk of losing more food.

Does one extra degree really save 3% of energy?

INRAE says that increasing frozen-food storage temperature by 1°C could save about 3% of the energy used by its cold chain. The principle is straightforward: the larger the gap between outdoor air and a cold enclosure, the harder a refrigeration system must work to remove heat entering through walls, doors, loading operations and air leaks.

But the percentage is not a guarantee for every freezer or warehouse. Energy use depends on insulation, door seals, compressor efficiency, ambient temperature, loading, door-opening frequency, defrosting and the temperature at which products arrive. An old, poorly maintained cold room may waste far more energy than a modern, well-controlled system.

The potential also has to be assessed across the full chain. Saving energy in a warehouse while allowing repeated temperature swings in transport may worsen the overall result. Stability comes first: monitor warm spots, find doors that do not close properly, avoid unnecessary openings and fix faults before they destroy a stock of food.

Cooling prevents waste, but it also affects the climate

The issue cannot be reduced to “less cooling means fewer emissions”. Refrigeration also stops perishable food from being lost before anyone can eat it. In a March 2026 article, the FAO reported that 526 million tonnes of food, about 12% of the global total, are lost or wasted because refrigeration is insufficient. This global figure mainly reflects gaps in infrastructure, temperature monitoring and storage in some regions; it does not describe the situation of a typical French household.

At the same time, a joint FAO and UN Environment Programme report estimates that the food cold chain accounts for around 4% of global greenhouse-gas emissions when emissions from cooling technologies and food loss caused by insufficient refrigeration are combined. Electricity is only part of the problem. Leaks of some refrigerants can also have a high global-warming effect.

The right goal is therefore to cut two forms of waste together: wasted energy and wasted food. A low-energy system that allows harvests to spoil is not sustainable. Neither is an oversized, poorly managed system powered by highly carbon-intensive energy.

How can the cold chain use less energy?

No single measure will solve the problem, but several practical levers reinforce one another.

  • Measure before adjusting. Well-placed sensors can identify warm areas and zones cooled more than necessary. Monitoring should reflect the product’s experience, not only the air next to the refrigeration unit.
  • Keep temperatures stable. Open doors, worn seals, ice build-up and blocked airflow all create variation. Maintenance and better loading practices avoid compensating for these faults with an unnecessarily low set point.
  • Match cooling to the product. Different foods require different treatment. INRAE’s research aims to link temperature, time, safety and quality instead of relying on one habit-based setting.
  • Improve equipment. Better insulation, efficient compressors, heat recovery and demand-based controls cut energy use. Where grid access is weak, FAO also points to decentralised solar systems designed for local needs.
  • Use low-impact refrigerants. Preventing leaks, recovering refrigerants at end of life and choosing options with low global-warming potential matter as much as reducing electricity use.
  • Shorten some journeys. When food can be eaten quickly near where it was harvested, a shorter supply chain may avoid days of storage. This does not remove safety duties: sensitive products must stay at their required temperature even on a short trip.

Should households change their freezer settings?

No, not because of this announcement. The regulatory reference for quick-frozen foods remains −18°C, and consumers should follow appliance instructions and package labels. INRAE’s figure describes research potential across a professional chain, not a new household recommendation.

Confusing frozen storage with ordinary refrigeration would be particularly risky. For sensitive chilled foods, the French food-safety agency Anses recommends keeping the coldest refrigerator area at 4°C. Arbitrarily raising the temperature can accelerate microbial growth. The agency also advises respecting use-by dates and placing high-risk foods in the coldest zone.

Safer household savings start elsewhere: check door seals, defrost when ice builds up, manage cooling and refrigerate cooked food promptly, without leaving it at room temperature for more than two hours, open doors briefly, keep ventilation paths clear and use a thermometer if the display is unreliable.

What does this mean for farms and local food networks?

For a farm, cooperative or growers’ market, cooling can determine whether a harvest keeps its value. Rapidly pre-cooling berries, leafy vegetables or certain animal products can extend the sales window. Yet expensive or poorly matched equipment can place a heavy burden on a small operation.

A shorter chain can sometimes provide more flexibility: harvest at maturity, announce available quantities quickly and organise nearby collection to reduce storage time. This works best for products that can safely be exchanged without long preservation. Meat, fish, dairy and prepared foods still require the applicable temperatures, traceability and hygiene, however short the distance.

In that context, Seeed enables individuals and producers to give away, sell or swap harvests and local products with people nearby. Quickly connecting a garden with too many courgettes to nearby residents can prevent a surplus from being forgotten. Seeed does not guarantee food safety or replace official controls; every listing should describe the product honestly and the relevant storage rules still apply.

What to remember

The cold chain is both protection and consumption. It preserves the safety, quality and shelf life of many foods while using energy and refrigerants. INRAE’s latest coverage shows that more precise settings may deliver meaningful savings, but the 3%-per-degree figure remains a potential that must be evaluated product by product and across the whole chain.

The strongest course today is not to “warm up freezers” at random. It is to measure better, maintain equipment, prevent temperature swings, choose efficient technology and find outlets quickly enough that food is not cooled for days only to be thrown away.

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