[Script Info]
Title: 
[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:06.88,0:00:09.30,Default,,0000,0000,0000,,Food doesn't last.
Dialogue: 0,0:00:09.30,0:00:12.65,Default,,0000,0000,0000,,In days, sometimes hours,\Nbread goes moldy,
Dialogue: 0,0:00:12.65,0:00:14.52,Default,,0000,0000,0000,,apple slices turn brown,
Dialogue: 0,0:00:14.52,0:00:17.88,Default,,0000,0000,0000,,and bacteria multiply in mayonnaise.
Dialogue: 0,0:00:17.88,0:00:22.11,Default,,0000,0000,0000,,But you can find all of these foods\Nout on the shelf at the grocery store,
Dialogue: 0,0:00:22.11,0:00:23.79,Default,,0000,0000,0000,,hopefully unspoiled,
Dialogue: 0,0:00:23.79,0:00:25.92,Default,,0000,0000,0000,,thanks to preservatives.
Dialogue: 0,0:00:25.92,0:00:28.06,Default,,0000,0000,0000,,But what exactly are preservatives?
Dialogue: 0,0:00:28.06,0:00:31.96,Default,,0000,0000,0000,,How do they help keep food edible\Nand are they safe?
Dialogue: 0,0:00:31.96,0:00:35.06,Default,,0000,0000,0000,,There are two major factors that cause\Nfood to go bad:
Dialogue: 0,0:00:35.06,0:00:37.57,Default,,0000,0000,0000,,microbes and oxidation.
Dialogue: 0,0:00:37.57,0:00:40.82,Default,,0000,0000,0000,,Microbes like bacteria and fungi\Ninvade food
Dialogue: 0,0:00:40.82,0:00:42.82,Default,,0000,0000,0000,,and feed off its nutrients.
Dialogue: 0,0:00:42.82,0:00:44.76,Default,,0000,0000,0000,,Some of these can cause diseases,
Dialogue: 0,0:00:44.76,0:00:47.31,Default,,0000,0000,0000,,like listeria and botulism.
Dialogue: 0,0:00:47.31,0:00:52.88,Default,,0000,0000,0000,,Others just turn edibles into a smelly,\Nslimy, moldy mess.
Dialogue: 0,0:00:52.88,0:00:57.20,Default,,0000,0000,0000,,Meanwhile, oxidation is a chemical change\Nin the food's molecules
Dialogue: 0,0:00:57.20,0:01:02.02,Default,,0000,0000,0000,,caused by enzymes or free radicals\Nwhich turn fats rancid
Dialogue: 0,0:01:02.02,0:01:05.50,Default,,0000,0000,0000,,and brown produce, \Nlike apples and potatoes.
Dialogue: 0,0:01:05.50,0:01:09.76,Default,,0000,0000,0000,,Preservatives can prevent both types\Nof deterioration.
Dialogue: 0,0:01:09.76,0:01:12.35,Default,,0000,0000,0000,,Before the invention of artificial\Nrefrigeration,
Dialogue: 0,0:01:12.35,0:01:16.23,Default,,0000,0000,0000,,fungi and bacteria could \Nrun rampant in food.
Dialogue: 0,0:01:16.23,0:01:21.17,Default,,0000,0000,0000,,So we found ways to create an inhospitable\Nenvironment for microbes.
Dialogue: 0,0:01:21.17,0:01:25.41,Default,,0000,0000,0000,,For example, making the food more acidic\Nunravels enzymes
Dialogue: 0,0:01:25.41,0:01:27.86,Default,,0000,0000,0000,,that microbes need to survive.
Dialogue: 0,0:01:27.86,0:01:30.65,Default,,0000,0000,0000,,And some types of bacteria \Ncan actually help.
Dialogue: 0,0:01:30.65,0:01:34.44,Default,,0000,0000,0000,,For thousands of years, people preserved\Nfood using bacteria
Dialogue: 0,0:01:34.44,0:01:37.26,Default,,0000,0000,0000,,that produce lactic acid.
Dialogue: 0,0:01:37.26,0:01:39.88,Default,,0000,0000,0000,,The acid turns perishable vegetables\Nand milk
Dialogue: 0,0:01:39.88,0:01:42.02,Default,,0000,0000,0000,,into longer lasting foods,
Dialogue: 0,0:01:42.02,0:01:43.80,Default,,0000,0000,0000,,like sauerkraut in Europe,
Dialogue: 0,0:01:43.80,0:01:45.24,Default,,0000,0000,0000,,kimchi in Korea,
Dialogue: 0,0:01:45.24,0:01:47.52,Default,,0000,0000,0000,,and yogurt in the Middle East.
Dialogue: 0,0:01:47.52,0:01:52.88,Default,,0000,0000,0000,,These cultured foods also populate your\Ndigestive track with beneficial microbes.
Dialogue: 0,0:01:52.88,0:01:56.72,Default,,0000,0000,0000,,Many synthetic preservatives \Nare also acids.
Dialogue: 0,0:01:56.72,0:01:58.66,Default,,0000,0000,0000,,Benzoic acid in salad dressing,
Dialogue: 0,0:01:58.66,0:02:00.64,Default,,0000,0000,0000,,sorbic acid in cheese,
Dialogue: 0,0:02:00.64,0:02:03.70,Default,,0000,0000,0000,,and propionic acid in baked goods.
Dialogue: 0,0:02:03.70,0:02:04.85,Default,,0000,0000,0000,,Are they safe?
Dialogue: 0,0:02:04.85,0:02:08.66,Default,,0000,0000,0000,,Some studies suggest that benzoates,\Nrelated to benzoic acid,
Dialogue: 0,0:02:08.66,0:02:11.64,Default,,0000,0000,0000,,contribute to hyperactive behavior.
Dialogue: 0,0:02:11.64,0:02:14.10,Default,,0000,0000,0000,,But the results aren't conclusive.
Dialogue: 0,0:02:14.10,0:02:17.56,Default,,0000,0000,0000,,Otherwise, these acids seem to be\Nperfectly safe.
Dialogue: 0,0:02:17.56,0:02:22.84,Default,,0000,0000,0000,,Another antimicrobial strategy is to add\Na lot of sugar, like in jam,
Dialogue: 0,0:02:22.84,0:02:25.80,Default,,0000,0000,0000,,or salt, like in salted meats.
Dialogue: 0,0:02:25.80,0:02:30.11,Default,,0000,0000,0000,,Sugar and salt hold on to water\Nthat microbes need to grow
Dialogue: 0,0:02:30.11,0:02:35.01,Default,,0000,0000,0000,,and actually suck moisture out\Nof any cells that may be hanging around,
Dialogue: 0,0:02:35.01,0:02:36.95,Default,,0000,0000,0000,,thus destroying them.
Dialogue: 0,0:02:36.95,0:02:40.88,Default,,0000,0000,0000,,Of course, too much sugar and salt\Ncan increase your risk of heart disease,
Dialogue: 0,0:02:40.88,0:02:41.73,Default,,0000,0000,0000,,diabetes,
Dialogue: 0,0:02:41.73,0:02:43.15,Default,,0000,0000,0000,,and high blood pressure,
Dialogue: 0,0:02:43.15,0:02:46.63,Default,,0000,0000,0000,,so these preservatives \Nare best in moderation.
Dialogue: 0,0:02:46.63,0:02:51.07,Default,,0000,0000,0000,,Antimicrobial nitrates and nitrites,\Noften found in cured meats,
Dialogue: 0,0:02:51.07,0:02:56.46,Default,,0000,0000,0000,,ward off the bacteria that cause botulism,\Nbut they may cause other health problems.
Dialogue: 0,0:02:56.46,0:02:58.86,Default,,0000,0000,0000,,Some studies linking cured meats to cancer
Dialogue: 0,0:02:58.86,0:03:02.100,Default,,0000,0000,0000,,have suggested that these preservatives\Nmay be the culprit.
Dialogue: 0,0:03:02.100,0:03:06.74,Default,,0000,0000,0000,,Meanwhile, antioxidant preservatives\Nprevent the chemical changes
Dialogue: 0,0:03:06.74,0:03:10.64,Default,,0000,0000,0000,,that can give food an off-flavor or color.
Dialogue: 0,0:03:10.64,0:03:13.45,Default,,0000,0000,0000,,Smoke has been used to preserve food\Nfor millennia
Dialogue: 0,0:03:13.45,0:03:18.33,Default,,0000,0000,0000,,because some of the aromatic compounds\Nin wood smoke are antioxidants.
Dialogue: 0,0:03:18.33,0:03:22.60,Default,,0000,0000,0000,,Combining smoking with salting was an\Neffective way of preserving meat
Dialogue: 0,0:03:22.60,0:03:24.68,Default,,0000,0000,0000,,before refrigeration.
Dialogue: 0,0:03:24.68,0:03:27.62,Default,,0000,0000,0000,,For antioxidant activity \Nwithout a smoky flavor,
Dialogue: 0,0:03:27.62,0:03:30.77,Default,,0000,0000,0000,,there are compounds like BHT\Nand tocopherol,
Dialogue: 0,0:03:30.77,0:03:33.08,Default,,0000,0000,0000,,better known as vitamin E.
Dialogue: 0,0:03:33.08,0:03:36.88,Default,,0000,0000,0000,,Like the compounds in smoke,\Nthese sop up free radicals
Dialogue: 0,0:03:36.88,0:03:39.26,Default,,0000,0000,0000,,and stave off rancid flavors
Dialogue: 0,0:03:39.26,0:03:41.23,Default,,0000,0000,0000,,that can develop in foods like oils,
Dialogue: 0,0:03:41.23,0:03:42.05,Default,,0000,0000,0000,,cheese,
Dialogue: 0,0:03:42.05,0:03:44.12,Default,,0000,0000,0000,,and cereal.
Dialogue: 0,0:03:44.12,0:03:47.30,Default,,0000,0000,0000,,Other antioxidants like citric acid\Nand ascorbic acid
Dialogue: 0,0:03:47.30,0:03:49.80,Default,,0000,0000,0000,,help cut produce keep its color
Dialogue: 0,0:03:49.80,0:03:53.27,Default,,0000,0000,0000,,by thwarting the enzyme \Nthat causes browning.
Dialogue: 0,0:03:53.27,0:03:56.27,Default,,0000,0000,0000,,Some compounds \Nlike sulfites can multitask.
Dialogue: 0,0:03:56.27,0:04:00.12,Default,,0000,0000,0000,,They're both antimicrobials\Nand antioxidants.
Dialogue: 0,0:04:00.12,0:04:03.24,Default,,0000,0000,0000,,Sulfites may cause allergy symptoms\Nin some people,
Dialogue: 0,0:04:03.24,0:04:08.96,Default,,0000,0000,0000,,but most antioxidant preservatives\Nare generally recognized as safe.
Dialogue: 0,0:04:08.96,0:04:11.33,Default,,0000,0000,0000,,So should you be worried \Nabout preservatives?
Dialogue: 0,0:04:11.33,0:04:14.52,Default,,0000,0000,0000,,Well, they're usually near the end\Nof the ingredients list
Dialogue: 0,0:04:14.52,0:04:16.78,Default,,0000,0000,0000,,because they're used \Nin very small amounts
Dialogue: 0,0:04:16.78,0:04:19.84,Default,,0000,0000,0000,,determined by the FDA to be safe.
Dialogue: 0,0:04:19.84,0:04:22.49,Default,,0000,0000,0000,,Nevertheless, some consumers\Nand companies
Dialogue: 0,0:04:22.49,0:04:24.92,Default,,0000,0000,0000,,are trying to find alternatives.
Dialogue: 0,0:04:24.92,0:04:29.33,Default,,0000,0000,0000,,Packaging tricks, like reducing\Nthe oxygen around the food can help,
Dialogue: 0,0:04:29.33,0:04:31.68,Default,,0000,0000,0000,,but without some kind \Nof chemical assistance,
Dialogue: 0,0:04:31.68,0:04:36.25,Default,,0000,0000,0000,,there are very few foods that can\Nstay shelf stable for long.