1 00:00:02,440 --> 00:00:04,960 Speaker 1: Welcome to brain Stuff, a production of I Heart Radio. 2 00:00:07,720 --> 00:00:10,320 Speaker 1: Hey brain Stuff, Lauren Vogel Bomb here with another classic 3 00:00:10,360 --> 00:00:13,440 Speaker 1: episode from our archives. As we're in the midst of 4 00:00:13,480 --> 00:00:16,200 Speaker 1: the fall season here in the United States, many people 5 00:00:16,200 --> 00:00:19,360 Speaker 1: are starting to think about holiday feasts, perhaps including a 6 00:00:19,440 --> 00:00:23,160 Speaker 1: brined turkey or a ham cured with salt. Aside from 7 00:00:23,200 --> 00:00:29,520 Speaker 1: being tasty, these preparations helped preserve meat. Here's why, Hey 8 00:00:29,600 --> 00:00:32,839 Speaker 1: brain Stuff, Lauren Vogel bam here, let's talk salt. You 9 00:00:32,920 --> 00:00:35,320 Speaker 1: might toss a little over your left shoulder for good luck, 10 00:00:35,479 --> 00:00:37,839 Speaker 1: sprinkle some on your eggs, or even tip a shaker 11 00:00:37,840 --> 00:00:40,680 Speaker 1: into a frothy beer. However you use it, one thing's 12 00:00:40,720 --> 00:00:44,040 Speaker 1: for certain. Most of us take salt for granted. Salt 13 00:00:44,120 --> 00:00:46,600 Speaker 1: wasn't always such a simple matter. For centuries, it was 14 00:00:46,640 --> 00:00:49,960 Speaker 1: a rare commodity, used as payment, as an impetus for wars, 15 00:00:50,080 --> 00:00:53,519 Speaker 1: and often for survival. Salt preserved fish and ancient Egypt 16 00:00:53,840 --> 00:00:56,880 Speaker 1: seasoned Roman salad dressings, and even came to stand for 17 00:00:56,920 --> 00:01:00,200 Speaker 1: a measure of a person's integrity. A competent Roman soldier 18 00:01:00,320 --> 00:01:02,600 Speaker 1: was worth his salt, had earned his allowance of the 19 00:01:02,680 --> 00:01:06,440 Speaker 1: valuable seasoning. But more than being tasty, salt kept entire 20 00:01:06,480 --> 00:01:09,720 Speaker 1: civilizations alive thanks to his ability to prevent foods from 21 00:01:09,720 --> 00:01:14,560 Speaker 1: turning into bacterial Latin killers. To understand how salt prevents 22 00:01:14,560 --> 00:01:17,440 Speaker 1: foods from spoiling, it's important to first grasp how it's 23 00:01:17,600 --> 00:01:21,080 Speaker 1: used to preserve foods. Salt is used in two primary ways, 24 00:01:21,200 --> 00:01:24,280 Speaker 1: either in granule form or in brine form, a brine 25 00:01:24,280 --> 00:01:27,600 Speaker 1: being a water and salt solution. A ham, for example, 26 00:01:27,680 --> 00:01:30,520 Speaker 1: might be cured with salt, and cucumbers are preserved and 27 00:01:30,560 --> 00:01:34,280 Speaker 1: turned into pickles with brine. Curing with salt granules, known 28 00:01:34,319 --> 00:01:37,240 Speaker 1: as dry curing, means applying salt to the outside of 29 00:01:37,240 --> 00:01:39,199 Speaker 1: a cut of meat and storing it for a couple 30 00:01:39,200 --> 00:01:41,560 Speaker 1: of days up to several weeks. It's one of the 31 00:01:41,560 --> 00:01:44,639 Speaker 1: most ancient ways of curing meats. Modern curing can involve 32 00:01:44,640 --> 00:01:47,800 Speaker 1: injecting meat with salt brine. Whatever the form of salt 33 00:01:47,800 --> 00:01:50,520 Speaker 1: it's used, the mineral preserves foods and makes them safer 34 00:01:50,560 --> 00:01:54,120 Speaker 1: to eat by preventing bacteria from growing, including the bacteria 35 00:01:54,160 --> 00:01:57,000 Speaker 1: that break down rotting food and also food board pathogens 36 00:01:57,000 --> 00:02:00,120 Speaker 1: such as salmonella, which can cause food poisoning, typhoid eiver, 37 00:02:00,280 --> 00:02:04,240 Speaker 1: and other serious problems. Salt inhibits bacteria in a variety 38 00:02:04,280 --> 00:02:07,440 Speaker 1: of ways. It's a disruptor that reeks havoc in microbes, 39 00:02:07,480 --> 00:02:10,680 Speaker 1: interrupting their enzymes and chipping away at their DNA. It 40 00:02:10,760 --> 00:02:13,679 Speaker 1: most often works through dehydration, though removing many of the 41 00:02:13,720 --> 00:02:17,320 Speaker 1: water molecules the bacteria need to live and grow. Water 42 00:02:17,400 --> 00:02:20,720 Speaker 1: molecules and food are measured in terms of product water activity, 43 00:02:21,120 --> 00:02:24,640 Speaker 1: a number that signifies the free water molecules present before 44 00:02:24,639 --> 00:02:28,200 Speaker 1: salt preservation. Many fresh foods have point nine nine product 45 00:02:28,200 --> 00:02:31,520 Speaker 1: water activity. The product water activity is lowered when salt 46 00:02:31,600 --> 00:02:35,160 Speaker 1: dehydrates the food through the process of lasmosis. In essence, 47 00:02:35,200 --> 00:02:37,760 Speaker 1: the salt around the outside of the food draws water 48 00:02:37,800 --> 00:02:41,440 Speaker 1: molecules out and replaces them with salt molecules until the 49 00:02:41,480 --> 00:02:44,800 Speaker 1: amount of salt is equal inside and out, lowering the 50 00:02:44,800 --> 00:02:48,119 Speaker 1: water product activity to point nine Ford point nine one 51 00:02:48,520 --> 00:02:56,880 Speaker 1: is usually sufficient to prevent most bacterial growth. Today's episode 52 00:02:56,880 --> 00:02:59,040 Speaker 1: was written by Laurie L. Dove and produced by Tristan 53 00:02:59,080 --> 00:03:02,440 Speaker 1: McNeil Entiler Clang. For more on this lots of other topics, 54 00:03:02,560 --> 00:03:05,320 Speaker 1: visit how stuff works dot com. Brain Stuff is production 55 00:03:05,360 --> 00:03:07,800 Speaker 1: of iHeart Radio. For more podcasts from my Heart Radio, 56 00:03:07,880 --> 00:03:10,600 Speaker 1: visit the iHeart Radio app, Apple podcasts, or wherever you 57 00:03:10,639 --> 00:03:11,920 Speaker 1: listen to your favorite shows.