Storage doesn’t only extend the season for local produce, but it’s also vital for moving food around the world. The apples from Argentina and New Zealand (where autumn harvest runs from February to early May) that are now filling supermarket shelves will probably have been kept in chilled warehouse storage in their country of origin before being loaded aboard refrigerated cargo ships to get to you. Back before refrigeration was commonplace, huge quantities of ice was chipped out of frozen lakes, rivers and ponds to keep food cool in shipment – ice was big business. By the 1860s, beef was being shipped in small amounts from the US to London, in heavily insulated cargo holds packed with ice and salt. Refrigeration systems had become established by the turn of the century, and by 1935 one million tonnes of meat, 500,000 tonnes of butter and 430,000 tonnes of apples and pears were being imported into the UK each year on refrigerated ‘reefer’ ships. These days, a relatively small proportion of the world’s cargo ships are true reefers, and it is increasingly common for cargoes of fruit and veg to be carried in individual refrigerated containers on standard container ships, meaning temperature can be controlled all the way from pack-house to wholesale or retail distribution centre.So back to our fruit, if we want to eat apples out of season what’s better from an environmental point of view? Months of chilled storage for UK apples, or refrigerated shipping from the southern hemisphere? A Defra funded study in 2008 found the answer was unequivocal – the total global warming potential from the lifecycle of imported New Zealand apples was 2.5-3 times greater than UK apples, even after UK apples had been kept in chilled storage for 5 months. So the message, for apples at least, remains… eat local, and eat seasonal(ish)! Working out the environmental footprints for the many possible combinations of production type, origin, storage, transport and so on for each different item of fruit and veg is a tricky business (the famous example, from the same Defra study, is that Spanish tomatoes generally have less GHG impact than supermarket UK tomatoes, despite transport), and there are no straightforward answers – but it seems that eating a variety of local, regional and UK-produced produce as close as possible to its natural seasonal rhythm is a good rule of thumb for fresh, tasty, low-impact food.