Summary: Cooling down foods can help to prevent / slow down spoiling making them last longer. Modern conventional refrigerators use the absorption and releasing of heat when a liquid changes to a gas and vice versa to cool the inside cabinet and keep food fresh. However, it is not without sustainability challenges including energy use and global warming potential of the refrigerants (the liquid/gas) used. We introduce briefly two alternatives that are still at early stages that could use much less energy and less harmful materials.
Why this is important: Refrigeration and freezing are important tools in helping food to last longer. If we can make those processes less energy hungry and with lower impact on the environment they can be more sustainable.
The big theme: There are real concerns about our ability to feed the world, while at the same time trying to reduce the impacts on our natural world. Agriculture and the food and beverage industries sit at the intersection of a number of UN Sustainable Development Goals. The goals are either directly relevant (for example, goal 2: zero hunger) or have a causal relationship (for example, education improving with better nutrition and less pollution). Reforming these industries is going to require massive social and economic change and disruption to production methods, to supply chains and to employment.
How foods go bad
There are a number of key mechanisms for spoiling food or making it unfit for us to eat.