Along with the many environmental problems posed by global climate change, an increase in ambient temperature could have negative effects on food safety everywhere, but particularly in developing countries.

That’s the message of a 2010 study in “Food Research International,”  which investigates the varied effects of climate change on the “cold-chain”–a term that refers to the uninterrupted steps in refrigerated storage and distribution necessary to keep perishable food fresh and safe.

In particular, the study warns, developing nations and developed ones in the Southern Hemisphere face food security issues brought on not only by extreme weather shifts, but also less dramatic climate changes.

Over the past 50 years, many of these areas have shifted away from their traditionally domestic food markets and now rely on importing food while they grow and export monoculture crops.  Monocultures are particularly vulnerable to environmental changes, which could leave countries that import the majority of their food at risk.

The international trade of food relies on a substantial investment of energy in the “cold-chain.”  Refrigeration slows the growth of potential pathogens, delays rotting and discoloration, inhibits the creation of amines, and lessens water loss.  That being said, only 10 percent of perishable foods are kept cool worldwide.  This amounts to nearly 200 million tons of food lost to rot every year–14 percent of the total consumption in developing nations.  Refrigerating perishables could help alleviate both hunger and foodborne illness in many places.

Because microbial growth is extremely temperature dependent, a change in temperature of a few degrees can have a dramatic effect on the growth of pathogens like Salmonella and Campylobacter in food such as poultry.  As a result, foodborne illnesses follow seasonal trends with more cases in the warmer months.  The fear is that as global temperatures increase, this trend will be extended later into what is now the cold season.


In the United Kingdom the rise in temperature could lead to 10,000 additional cases of foodborne illness per year, estimates suggest.  Australia’s estimates are much higher–79,000 additional cases per year by 2050, following the prediction that the Southern Hemisphere will be hit far harder by climate change.

But expanding the cold-chain raises a parallel concern: the emissions created by cooling food.  While maintaining temperature control from farm to dinner plate preserves the quality and safety of the food, the refrigeration along the way accounts for 15 percent of global electricity usage.  On a national level, 2.4 percent of UK greenhouse gas emissions are due to refrigeration, the authors say.  

As global temperatures rise, that percentage is expected to increase.  An increase in temperatures of only 2-3ºC would halve the shelf life of food, so refrigeration would have to increase to maintain a safe food supply.

While refrigeration of perishable foods would simultaneously reduce the amount lost post-harvest and increase food safety, expanding the current forms of refrigeration could lead to increased greenhouse gas emission, the root cause of the climate change threatening food supplies.