Why is Salt used for Food Preservations??

Answer 1

The answer Aldo gave is pretty good, but doesn't quite address the basic concept of salting.

The only basic principle needed is that any substance likes to spread out/disperse/diffuse until its concentration is uniform through out the occupied space, I think this one is pretty clear.

What happens when you salt meat in order to preserve it works in the same principle. Microorganisms that could multiple and spoil meat are made of water-containing cells. The cells are surrounded by semipermeable membrane, just a fancy word meaning the holes are only large enough for water molecules to pass through, but small enough to keep everything else inside.

Once salt is introduced to the meat, there is more salt outside of microbes than inside. The first principle is to have salt diffuse throughout, but the problem of semipermeable member would not let salt enter into microbe cells. The end result is osmosis. Instead of moving salt, water is moved instead. Water moves out from inside of microbes' cells to outside in order to decrease the concentration of salt. This process continues until the concentration of salt both inside(inside of microbes) and outside(the meat) are exactly equal.

During this process, two mechanisms takes place that would destroy the spoilage microorganisms: this osmotic pressure of all the water rushing out of cells overcome the cellular structure that holds the cell's shape, like water bursting out of a damaged dam, literally destroying it. Secondly, without sufficient water inside of microbe's cell, many vital function cease to function and essentially kills the cells.

This is exactly how salting works, if you are interested in the gritty scientific explanation.

As a side note, this is also the reason why salt is bad for high blood pressure, the high salt content inside of human cells forces blood vessels to retain water instead of letting them out. Imagine a pipe that is being forced to hold more water than its capable - this is what salt does in hypertension, creating enormous, damaging pressure on the arterial walls.

Answer 2

Salt is a natural preservative because it dehydrates the bacteria that might spoil your food.

Think of the ends of your fingers when you have been swimming in the ocean for so long. The thumbprint areas are all wrinkly and wilted and look bad. You are lucky because you can always ran off back to land so that you will not be dehydrated.

Bacteria can't leave the container if they are immersed in a salty environment. Thus, eventually their cells shrink completely and they die. For cells to survive (humans and bacteria), a certain osmotic pressure must be preserved to maintain the integrity of the cell shape. The presence of salt outside the cells, makes the WATER inside the cell to osmose out of the cell causing uncontrolled shrinkage. Thus, they die.

However, there are other bacteria that can still survive even if they are in a salty medium. But for the most part, salt is the cheapest and readily available food preservative.

Now the effect of the salt on your food, be it plant or animal, will also cause the cells to die. But then, your food is already dead anyway!

Ha ha. sorry.

Answer 3

salt is a "natural" preservative. it can be added to foods that claim that there are no artificial preservatives in their product.

Answer 4

Salt and sugar remove water from the food which makes it a hostile place for bacteria. They cannot survive their internal fluids being drawn out either.

Answer 5

because salt pulls the moisture out of foods and is also very "poisonous" to bacteria. The lack of moisture and the salt kills and prevents bacteria from entering the food.

Answer 6

Salt removes water from the food (usually meat) which, if left, accelerates decay. If something is "salt-cured" the salt actually "cooks" the meat through the chemical reaction between the sodium and protein in the meat.

Answer 7

it is an ancient form of preserving food, it inhibits bacterial growth. think pickles.

Answer 8

ozmotic pressure caused by sodiam pervents spoilage

Answer 9

I slows down the growth of bacteria

Answer 10

to preserve it.