Speaker 1: Welcome to brain Stuff, a production of I Heart Radio.
Speaker 1: Hey brain Stuff, Lauren Vogel Bomb here with another classic
Speaker 1: episode from our archives. As we're in the midst of
Speaker 1: the fall season here in the United States, many people
Speaker 1: are starting to think about holiday feasts, perhaps including a
Speaker 1: brined turkey or a ham cured with salt. Aside from
Speaker 1: being tasty, these preparations helped preserve meat. Here's why, Hey
Speaker 1: brain Stuff, Lauren Vogel bam here, let's talk salt. You
Speaker 1: might toss a little over your left shoulder for good luck,
Speaker 1: sprinkle some on your eggs, or even tip a shaker
Speaker 1: into a frothy beer. However you use it, one thing's
Speaker 1: for certain. Most of us take salt for granted. Salt
Speaker 1: wasn't always such a simple matter. For centuries, it was
Speaker 1: a rare commodity, used as payment, as an impetus for wars,
Speaker 1: and often for survival. Salt preserved fish and ancient Egypt
Speaker 1: seasoned Roman salad dressings, and even came to stand for
Speaker 1: a measure of a person's integrity. A competent Roman soldier
Speaker 1: was worth his salt, had earned his allowance of the
Speaker 1: valuable seasoning. But more than being tasty, salt kept entire
Speaker 1: civilizations alive thanks to his ability to prevent foods from
Speaker 1: turning into bacterial Latin killers. To understand how salt prevents
Speaker 1: foods from spoiling, it's important to first grasp how it's
Speaker 1: used to preserve foods. Salt is used in two primary ways,
Speaker 1: either in granule form or in brine form, a brine
Speaker 1: being a water and salt solution. A ham, for example,
Speaker 1: might be cured with salt, and cucumbers are preserved and
Speaker 1: turned into pickles with brine. Curing with salt granules, known
Speaker 1: as dry curing, means applying salt to the outside of
Speaker 1: a cut of meat and storing it for a couple
Speaker 1: of days up to several weeks. It's one of the
Speaker 1: most ancient ways of curing meats. Modern curing can involve
Speaker 1: injecting meat with salt brine. Whatever the form of salt
Speaker 1: it's used, the mineral preserves foods and makes them safer
Speaker 1: to eat by preventing bacteria from growing, including the bacteria
Speaker 1: that break down rotting food and also food board pathogens
Speaker 1: such as salmonella, which can cause food poisoning, typhoid eiver,
Speaker 1: and other serious problems. Salt inhibits bacteria in a variety
Speaker 1: of ways. It's a disruptor that reeks havoc in microbes,
Speaker 1: interrupting their enzymes and chipping away at their DNA. It
Speaker 1: most often works through dehydration, though removing many of the
Speaker 1: water molecules the bacteria need to live and grow. Water
Speaker 1: molecules and food are measured in terms of product water activity,
Speaker 1: a number that signifies the free water molecules present before
Speaker 1: salt preservation. Many fresh foods have point nine nine product
Speaker 1: water activity. The product water activity is lowered when salt
Speaker 1: dehydrates the food through the process of lasmosis. In essence,
Speaker 1: the salt around the outside of the food draws water
Speaker 1: molecules out and replaces them with salt molecules until the
Speaker 1: amount of salt is equal inside and out, lowering the
Speaker 1: water product activity to point nine Ford point nine one
Speaker 1: is usually sufficient to prevent most bacterial growth. Today's episode
Speaker 1: was written by Laurie L. Dove and produced by Tristan
Speaker 1: McNeil Entiler Clang. For more on this lots of other topics,
Speaker 1: visit how stuff works dot com. Brain Stuff is production
Speaker 1: of iHeart Radio. For more podcasts from my Heart Radio,
Speaker 1: visit the iHeart Radio app, Apple podcasts, or wherever you
Speaker 1: listen to your favorite shows.