Everyone says you should seal whatever container you brine your meat with using tinfoil or airtight nylon. What are the reasons for this? 
I found this very informative article from the Crown Prince company, an anchovy canner and distributor.  Apparently the reason for cold storage has to do with the preservation process and product quality:     Anchovy Handling      Anchovies are a "semi-preserved" product. This means that they are not   sterilized by either cooking or pasteurization. Instead, anchovies are   preserved by a salting process whereby salt is used to control   bacteria which would otherwise render a canned product unusable.      The anchovies remain in the salt until just before canning. Therefore,   suppliers do not pack ahead of order. Our anchovies are not packed   until just prior to shipment.      Because they are "semi-preserved", anchovies will eventually break   down and become mushy. The cans may even puff. This occurs because   there is a non-harmful bacteria that survives in salt. This bacteria   can be inconvenient because when it grows it can eventually form a gas   which will puff the can. We repeat that this is not harmful to humans,   but is most inconvenient.      Heat will hasten the growth of the non-harmful bacteria. Anchovies   should always be stored in a cool place, preferably in the   refrigerator. Their shelf life when refrigerated is about 18 months.   If you do not plan on consuming the anchovies or paste immediately   after purchasing, we recommend storing them in the refrigerator. It is   important to note that puffed anchovy cans are not indicative of a   faulty canning procedure, but rather of improper storage subsequent to   canning.      Occasionally, customers complain of a white substance in the can.   Often, salt collects around the edges of the fish. This is harmless,   as it is only salt.  