system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: how are fruits kept fresh when being delivered across large distances like on cargo ships? Is it more than just refridgeration?

How come we cant keep fruit in the fridge for weeks?
gpt
Actually have some legitimate knowledge on this one.  

Odds are the fruit in your fridge has already been around for several days, weeks, or even months before a consumer gets to it. Between the fields, sorting, packing houses, distribution, and then onto store shelves it's been around a bit. Even more so if it isn't local.  

Things are picked during certain ripeness windows, forced ripening, refrigeration, air freight in some cases, specific varieties, chemistry witchcraft, and quality as well.       


In some cases it's possible to pick fruits before they are ripe, then store them in certain conditions where they will not be exposed to the ripening chemicals until desired. Humidity, temperature, gas mixture is all controlled for. Ethylene gas is one of them, if you've ever been told not to store other fruit near bananas it's because they give off a lot of it as they ripen which can force nearby fruits to prematurely spoil.. on the flip side the gas can be introduced closer to delivery to "finish" fruits.  
This isn't as high quality as tree ripened fruit(for citrus anyway) since it's more for color than flavor or juice, but will get the color right and keep the rind intact longer. Though once gassed, the decay process speeds up rapidly. This is also how supply for fruits are smoothed out over peaks and falls from different varieties having slightly different pick times. Not every fruit works with this method, but a lot of them do, even if it is just for color. Some fruits like bananas, or stone fruit do actually ripen and change flavor from the ripening. IIRC the term is climacteric vs non-climactic.       
Bananas are a great example of this. Picked green, straight into refer containers ASAP, then onto ships and gassed at receiving centers. Depending the cycle, location etc, the banana that will implode on a consumers counter in 2-3 days, is already two weeks old.  


Containers can be refrigerated which helps.  

If the commodity is expensive enough, it's possible to air shot it to destination. Berries are a common air freight commodity since they spoil fast but also can command a high price. Ever try to buy berries in NA during the winter and realize you're paying like $8 for a small clamshell grown in South America? Berries for people in the business are also a very high stress commodity since they perish extremely fast, are potentially a lot of profit and have tighter margins for freight times. I've heard anecdotes about brokers renting U-Hauls and driving the shipment themselves to make sure their shipments were on the plane. 

Some varieties have thicker skin and lend themselves to better export markets.   

In the case of apples, it's entirely possible with ~~witchcraft~~ chemistry to fully stop the decay and store them for months. Upon removal from the gas chambers the fruit begins to decay and ripen again though.    

Export fruit is also generally higher quality, both to survive the trips but also to make up for the higher cost to consumer. Some of the best fruit I've ever had is export grade straight from the fields.   

tl;dr- Commercial agriculture is a full science with massive chambers that control gas mixtures, temperature and humidity to control the decay. The average fridge, does not have that. Odds are also that the fruit has already been around for a while before ending up in a consumer fridge.