Are spotty fruits and vegetables safe to eat? - Elizabeth Brauer
-
0:07 - 0:10In 2010, $30 billion worth
of fruits and vegetables -
0:10 - 0:13were wasted by American retailers
and shoppers -
0:13 - 0:16in part because of cosmetic problems
and perceived spoilage. -
0:16 - 0:20That's a poor use of about 30%
of the produce on the market, -
0:20 - 0:25not to mention the water and energy
required to grow and transport it, -
0:25 - 0:28and the landfill space getting used up
by rotting fruit. -
0:28 - 0:30So what are those cosmetic problems?
-
0:30 - 0:33You've probably passed over
a spotty apple in the grocery store, -
0:33 - 0:38or accidentally sunk your thumb
into a mushy patch on a tomato. -
0:38 - 0:41These blemishes can doom produce
to the trash can. -
0:41 - 0:43But what are they anyway,
-
0:43 - 0:45and are they actually bad for you?
-
0:45 - 0:49Those spots are evidence of an epic battle
between plants and microbes. -
0:49 - 0:53Like humans, plants coexist with billions
of fungi and bacteria. -
0:53 - 0:56Some of these microbes are beneficial
to the plant, -
0:56 - 1:00suppressing disease and helping it
extract nutrients. -
1:00 - 1:02Others are pathogens,
attacking the produce, -
1:02 - 1:07still alive as it sits in a store display
or your refrigerator -
1:07 - 1:10and siphoning off molecules
they can use themselves. -
1:10 - 1:13The good news is
they're almost never bad for you. -
1:13 - 1:16These fungi and bacteria have spent
millions of years -
1:16 - 1:19developing strategies to overcome
a plant's immune system. -
1:19 - 1:22But healthy human immune systems
are different enough -
1:22 - 1:24that those strategies
just don't work on us. -
1:24 - 1:28So in a plant,
what does this process look like? -
1:28 - 1:31Microbes can reach plants
in a number of ways, -
1:31 - 1:35like getting splashed onto it
during watering or fertilization. -
1:35 - 1:37Under the right conditions,
-
1:37 - 1:39the microbes grow
into large enough colonies -
1:39 - 1:42to attack the waxy outer layer
of fruit or leaves. -
1:42 - 1:46Their target: the delicious sugars
and nutrients inside. -
1:46 - 1:50This type of pathogen often makes
spots like this. -
1:50 - 1:54A clump of bacteria drains the nutrients
and color from the fruit's cells -
1:54 - 1:56making that yellow halo.
-
1:56 - 1:57It then moves outward,
-
1:57 - 2:00leaving a black spot of dead cells
in its wake. -
2:00 - 2:03Each spot, which could contain
hundreds of thousands of microbes -
2:03 - 2:07is actually caused by a combination
of microbial attack -
2:07 - 2:09and the host defending itself.
-
2:09 - 2:14For example, this is the bacterial
pathogen Pseudomonas syringae. -
2:14 - 2:16Once on a tomato,
it enters the fruit and leaves, -
2:16 - 2:19multiplies in the space between the cells,
-
2:19 - 2:21and produces toxins and proteins
-
2:21 - 2:24that allow it to disrupt
the plant's immune response. -
2:24 - 2:28One toxin coronatine makes plants'
stomata open up, -
2:28 - 2:31allowing bacteria to enter
more freely. -
2:31 - 2:35Coronatine also activates pathways
leading to chlorophyll degradation, -
2:35 - 2:38which you can see as yellow spots.
-
2:38 - 2:40As the bacteria continue to feed
and multiply, -
2:40 - 2:42they start to kill off the plant cells.
-
2:42 - 2:46That explains spots,
but what about mushy blemishes? -
2:46 - 2:49Those are usually caused when the fruit
is attacked by microbes -
2:49 - 2:51after it's detached from the plant.
-
2:51 - 2:53If the plant is wounded during transport,
-
2:53 - 2:56necrotic fungi can infiltrate
through the wound, -
2:56 - 2:57kill the cells,
-
2:57 - 2:58absorb their nutrients,
-
2:58 - 3:01and leave your food
looking mushy or brown. -
3:01 - 3:04Those spots in particular
can taste pretty bad. -
3:04 - 3:06You're eating dead
and decomposing tissue, after all. -
3:06 - 3:09But you can usually salvage the rest
of the fruit. -
3:09 - 3:13The non-mushy spots, like the ones
you typically see on apples or tomatoes, -
3:13 - 3:17are just on the surface
and don't usually affect flavor. -
3:17 - 3:21Of course, microbes that do make us sick,
like E. coli and salmonella, -
3:21 - 3:23can hitch a ride on vegetables, too.
-
3:23 - 3:27But because they're not plant pathogens,
they don't typically cause spots. -
3:27 - 3:30They just hang out
invisibly on the surface. -
3:30 - 3:33So it's washing fruit and veggies,
not avoiding the spotty ones, -
3:33 - 3:35that will help you avoid getting sick.
-
3:35 - 3:37So the next time
you're at the grocery store, -
3:37 - 3:40don't be afraid
to pick up funky-looking fruit. -
3:40 - 3:42Some stores will even give you a discount.
-
3:42 - 3:44Wash them well and store them properly,
-
3:44 - 3:48as some produce like apples and cabbages
will keep in the fridge for weeks. -
3:48 - 3:53The spotty ones may not be eye candy,
but they're safe and just as delicious.
- Title:
- Are spotty fruits and vegetables safe to eat? - Elizabeth Brauer
- Description:
-
View full lesson: http://ed.ted.com/lessons/are-spotty-fruits-and-vegetables-safe-to-eat-elizabeth-brauer
In 2010, 30 billion dollars worth of fruits and vegetables were wasted by American retailers and shoppers, in part because of cosmetic problems and perceived spoilage. But what are these spots, anyway, and are they okay to eat? Elizabeth Brauer explains why you may not need to be afraid of picking up your grocery store’s funky-looking fruit.
Lesson by Elizabeth Brauer, animation by TED-Ed.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 04:09
Jessica Ruby approved English subtitles for Are spotty fruits and vegetables safe to eat? - Elizabeth Brauer | ||
Jessica Ruby accepted English subtitles for Are spotty fruits and vegetables safe to eat? - Elizabeth Brauer | ||
Jessica Ruby edited English subtitles for Are spotty fruits and vegetables safe to eat? - Elizabeth Brauer | ||
Jennifer Cody edited English subtitles for Are spotty fruits and vegetables safe to eat? - Elizabeth Brauer |