Are food preservatives bad for you? - Eleanor Nelsen
-
0:07 - 0:09Food doesn't last.
-
0:09 - 0:13In days, sometimes hours,
bread goes moldy, -
0:13 - 0:15apple slices turn brown,
-
0:15 - 0:18and bacteria multiply in mayonnaise.
-
0:18 - 0:22But you can find all of these foods
out on the shelf at the grocery store, -
0:22 - 0:24hopefully unspoiled,
-
0:24 - 0:26thanks to preservatives.
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0:26 - 0:28But what exactly are preservatives?
-
0:28 - 0:32How do they help keep food edible
and are they safe? -
0:32 - 0:35There are two major factors that cause
food to go bad: -
0:35 - 0:38microbes and oxidation.
-
0:38 - 0:41Microbes like bacteria and fungi
invade food -
0:41 - 0:43and feed off its nutrients.
-
0:43 - 0:45Some of these can cause diseases,
-
0:45 - 0:47like listeria and botulism.
-
0:47 - 0:53Others just turn edibles into a smelly,
slimy, moldy mess. -
0:53 - 0:57Meanwhile, oxidation is a chemical change
in the food's molecules -
0:57 - 1:02caused by enzymes or free radicals
which turn fats rancid -
1:02 - 1:06and brown produce,
like apples and potatoes. -
1:06 - 1:10Preservatives can prevent both types
of deterioration. -
1:10 - 1:12Before the invention of artificial
refrigeration, -
1:12 - 1:16fungi and bacteria could
run rampant in food. -
1:16 - 1:21So we found ways to create an inhospitable
environment for microbes. -
1:21 - 1:25For example, making the food more acidic
unravels enzymes -
1:25 - 1:28that microbes need to survive.
-
1:28 - 1:31And some types of bacteria
can actually help. -
1:31 - 1:34For thousands of years, people preserved
food using bacteria -
1:34 - 1:37that produce lactic acid.
-
1:37 - 1:40The acid turns perishable vegetables
and milk -
1:40 - 1:42into longer lasting foods,
-
1:42 - 1:44like sauerkraut in Europe,
-
1:44 - 1:45kimchi in Korea,
-
1:45 - 1:48and yogurt in the Middle East.
-
1:48 - 1:53These cultured foods also populate your
digestive track with beneficial microbes. -
1:53 - 1:57Many synthetic preservatives
are also acids. -
1:57 - 1:59Benzoic acid in salad dressing,
-
1:59 - 2:01sorbic acid in cheese,
-
2:01 - 2:04and propionic acid in baked goods.
-
2:04 - 2:05Are they safe?
-
2:05 - 2:09Some studies suggest that benzoates,
related to benzoic acid, -
2:09 - 2:12contribute to hyperactive behavior.
-
2:12 - 2:14But the results aren't conclusive.
-
2:14 - 2:18Otherwise, these acids seem to be
perfectly safe. -
2:18 - 2:23Another antimicrobial strategy is to add
a lot of sugar, like in jam, -
2:23 - 2:26or salt, like in salted meats.
-
2:26 - 2:30Sugar and salt hold on to water
that microbes need to grow -
2:30 - 2:35and actually suck moisture out
of any cells that may be hanging around, -
2:35 - 2:37thus destroying them.
-
2:37 - 2:41Of course, too much sugar and salt
can increase your risk of heart disease, -
2:41 - 2:42diabetes,
-
2:42 - 2:43and high blood pressure,
-
2:43 - 2:47so these preservatives
are best in moderation. -
2:47 - 2:51Antimicrobial nitrates and nitrites,
often found in cured meats, -
2:51 - 2:56ward off the bacteria that cause botulism,
but they may cause other health problems. -
2:56 - 2:59Some studies linking cured meats to cancer
-
2:59 - 3:03have suggested that these preservatives
may be the culprit. -
3:03 - 3:07Meanwhile, antioxidant preservatives
prevent the chemical changes -
3:07 - 3:11that can give food an off-flavor or color.
-
3:11 - 3:13Smoke has been used to preserve food
for millennia -
3:13 - 3:18because some of the aromatic compounds
in wood smoke are antioxidants. -
3:18 - 3:23Combining smoking with salting was an
effective way of preserving meat -
3:23 - 3:25before refrigeration.
-
3:25 - 3:28For antioxidant activity
without a smoky flavor, -
3:28 - 3:31there are compounds like BHT
and tocopherol, -
3:31 - 3:33better known as vitamin E.
-
3:33 - 3:37Like the compounds in smoke,
these sop up free radicals -
3:37 - 3:39and stave off rancid flavors
-
3:39 - 3:41that can develop in foods like oils,
-
3:41 - 3:42cheese,
-
3:42 - 3:44and cereal.
-
3:44 - 3:47Other antioxidants like citric acid
and ascorbic acid -
3:47 - 3:50help cut produce keep its color
-
3:50 - 3:53by thwarting the enzyme
that causes browning. -
3:53 - 3:56Some compounds
like sulfites can multitask. -
3:56 - 4:00They're both antimicrobials
and antioxidants. -
4:00 - 4:03Sulfites may cause allergy symptoms
in some people, -
4:03 - 4:09but most antioxidant preservatives
are generally recognized as safe. -
4:09 - 4:11So should you be worried
about preservatives? -
4:11 - 4:15Well, they're usually near the end
of the ingredients list -
4:15 - 4:17because they're used
in very small amounts -
4:17 - 4:20determined by the FDA to be safe.
-
4:20 - 4:22Nevertheless, some consumers
and companies -
4:22 - 4:25are trying to find alternatives.
-
4:25 - 4:29Packaging tricks, like reducing
the oxygen around the food can help, -
4:29 - 4:32but without some kind
of chemical assistance, -
4:32 - 4:36there are very few foods that can
stay shelf stable for long.
- Title:
- Are food preservatives bad for you? - Eleanor Nelsen
- Description:
-
View full lesson: http://ed.ted.com/lessons/are-preservatives-bad-for-you-eleanor-nelsen
Food doesn’t last. In days, sometimes hours, bread goes moldy, apple slices turn brown, and bacteria multiply in mayonnaise. But you can find all of these foods out on the shelf at the grocery store — hopefully unspoiled -- thanks to preservatives. But what exactly are preservatives? How do they help keep food edible? And are they safe? Eleanor Nelsen investigates.
Lesson by Eleanor Nelsen, animation by Compote Collective.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 04:53
Jessica Ruby edited English subtitles for Are preservatives bad for you? - Eleanor Nelsen | ||
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Jessica Ruby accepted English subtitles for Are preservatives bad for you? - Eleanor Nelsen | ||
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