Food preservation may be defined as the process of treating and handling food to prevent it from reaching a state where it would be unfit for human consumption. Preserving food goes way back in human history, since prehistoric times. This is done so because food—despite their abundant sources—was always in scarce supply, especially when the primary methods of food acquisition were hunting and gathering.
Mostly, the aim of food preservation is to prevent it from accumulating bacteria and fungi which are harmful and oftentimes lethal to humans, and food preservation has evolved with humankind all throughout its history.
Some of the simplest methods from the earliest times that are still being practiced nowadays are: drying, refrigeration, salting and pickling.
Drying, which is one of the oldest method of food preservation, involves putting the food out in the sun to dry, thereby wringing out moisture in order to delay or in some cases, prevent bacterial growth.
Refrigeration also works by slowing down fungal and bacterial growth by subjecting the food to very low temperatures where such bacteria will not develop. Though refrigeration is one of the oldest methods of food preservation, it’s a technique that most people could not do particularly those living in warm climates. It was not until the introduction of commercial refrigeration that the method was made available to anyone, anywhere, making refrigeration one of the—if not the most common method of preserving food all over the world.
Salting works by drawing out the moisture from the meat through osmosis. Salting is also commonly known as curing, though it may also involve other reagents other than salt, such as sugar, or even a combination of salt and sugar.
Pickling, is also used to preserve food, but instead of inhibiting bacterial growth, fermentation actually encourages it. Certain microorganisms are actually conducive to keeping the food in an edible condition and the pickled food are immersed in a liquid solution that inhibits bad bacteria from growing while encouraging helpful bacteria. Kimchi, sauerkraut, beer and yogurt are more common examples of how good bacteria can help.
However, the typical pickling processes involves outright inhibiting bacterial growth and often involve agents such as brine water (water high in salinity content), alcohol, vinegar and certain oils such as vegetable oil and olive oils. Such examples include eggs, cucumbers, peppers, and corned beef.
Though the methods usually involve stunting the growth of bacteria and fungi, there are some that actually encourage their growth, such as in pasteurization and fermentation. Pasteurization, in particular, generally involves controlled heating of the food in liquid—not to eliminate bad bacteria, but to filter out those bad microbes that will prove harmful for human consumption and leaving the “good” bacteria behind. Dairy products are what usually comes to mind when people think of pasteurization, and so does beer and wine.
Food preservation has of course, improved with civilization and as technology and commercialism race forward, the various methods of preserving food increase and improve as well.