July 3, 2019 • 7 mins
Canning foods preserves them, but the texture and nutritive value can suffer -- and what about the potential dangers of BPA and botulism? Learn what's true and what's myth when it comes to canned food in this episode of BrainStuff.
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Episode Transcript
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Speaker 1 (00:01):
Welcome to brain Stuff production of I Heart Radio. Hey
brain Stuff, Lauren Vogle Bam. Here, Let's face it, some
canned vegetables are so very different from their fresh forms,
think asparagus, that plenty of kids grow up swearing off
otherwise delicious foods forever. So it's no surprise that canned
foods have a bad rap. But the bad reputation goes
(00:25):
beyond just the food that comes inside those cans. It's
also because of things like the growth of farmers markets
in the last twenty years, and influencers like California's Alice
Waters and Michael Pollen who have encouraged eating locally raised
fresh foods over processed foods, and bp A linings and
scary accounts of the dangers of dented cans told by
well meaning grandparents. So is that bad reputation deserved? First,
(00:50):
Let's back up and talk about canning foods as a whole.
Canning was born out of a search for convenience and efficiency.
A French candy maker and chef Nicholas A. Pear develop
to the process. At the end of the eighteenth century,
Napoleon was offering a huge prize to anyone who could
help him feed his troops. A pair's original process isn't
very different from the canning methods used today. A pair
(01:11):
put food in bottles and jars, covered them with cork
and wax, and processed the jars in boiling water. The
French government paid a pair to make his process public,
and that led to the first recipe book on canning.
The Pair's process spread quickly. Not twenty years later, the
British Navy fed soldiers the first meat, soups and vegetables
that were canned in tin instead of jars. During World
(01:34):
War Two, governments in a number of countries, including the
U S and the UK, promoted home canning. The U
S printed and distributed circulars and opened thousands of canning
centers to help home cooks preserve food grown in home gardens.
Canning became patriotic, supplementing bland and sometimes inadequate rations. In
the nineteen fifties, commercially canned and other packaged foods were
(01:56):
introduced as nutritious, time saving, modern convenient. A popular book,
the can Opener cookbook Buy Food, editor Poppy Cannon promised
readers they could open some cans and create a gourmet
meal without really knowing how to cook. The recipes included
roast canned chicken flombay with black cherries made with a
whole canned chicken. Another meal was made of canned hamburger
(02:18):
patties covered with fried onions and red wine, baked in
a castrole dish for twenty minutes. Canned food was promoted
and seen as better than fresh, especially as industrial agriculture
began to incorporate more modern fertilizers and technologies. The author
of the can Opener cookbook wrote the flavor of fresh
tomatoes was bad and that for real tomato flavor, you
(02:38):
should open a can. Fifty is years later, canned tomatoes
are still an off season go to for tomato lovers
and cooks, and I certainly can't deny the convenience of
a can of beans already cooked and ready to go
into a salad, soup, dip, or whatever other dish, no
long soaking or par boiling required. From a nutrition standpoint,
the canning process today is designed preserve as many nutrients
(03:01):
as possible. Fruits and vegetables for canning are picked at
the peak of their ripeness, as opposed to some produce
picked for fresh sale, which may be underripe to prevent
spoilage during transport from farmed store. Crops destined for canning
are grown close to packing facilities and can be processed
within four hours of harvest. The heat used during canning
does decrease some of the water soluble vitamins in the
(03:23):
finished food, like vitamins B and C, and often salt
and sugar are added during the process. Experts suggest rinsing
canned food to reduce some of the added sugar and salt,
or buying low salt and low sugar products. And of
course that heat also changes the texture of vegetables, regrettably
so in the case of those canned asparagus. But that
heat is a plus when it comes to food safety.
(03:45):
The heat introduces pressure that helps seal the cans, but
it can also kill or deactivate deadly germs. Remember when
we mentioned our grandparents aversions to dented or swollen cans.
Those fears are based in reality. Let's talk about my face.
Its scary condition botuli um. It's caused by a bacterial
toxin so deadly that just a million of a graham
(04:06):
is enough to kill the United States and other countries
even explored botulism as a biological weapon during World War Two.
The bacteria that crete this toxin, clostradian batu linum, are everywhere,
but people associate bauchuli ism with canned foods because the
bacteria only reproduce in low oxygen environments like a poorly
processed can. Today, commercial canned foods go through what's called
(04:29):
a bochu linum cook. This is a high heat cook
that dramatically lowers the chance that any Clustradiu bauchua linum
spores or other organisms that can cause food born illness survive.
For the record, you should discard any can that's puffed
out or swollen that's caused by germs reproducing inside of it,
and it is bad news. Cans that are dented are
usually fine, as long as the dent is not along
(04:51):
the cans scenes. The most recent concern about canned foods, though,
isn't the food at all. It's the cans themselves and
what they're lined with, including b p A. Over the
past two decades, public attention has focused on bp A,
the compound used to make polycarbonate plastics and epoxy resins.
In two thousand and eight, the US government's National Toxicology
(05:13):
Program concluded that there was concern about its effects on
the brains, behavior, and prostate glands of fetuses, infants, and children.
Other studies have linked BPA to cardiovascular disease, obesity, asthma,
and diabetes. B p A exposure is widespread. The Centers
for Disease Control found b p A and of the
urine samples of more than twenty five thousand people aged
(05:35):
six and older. B p A can leach from containers,
including cans, into foods and drinks, and so plastics and
canning manufacturers have worked to develop replacement materials. The Canned
Manufacturers Institute says more than of food cans today are
lined with new b p A free materials such as polyesters, acrylics,
and PVC. Though note that that figure just refers to
(05:59):
food cans. It doesn't include canned drinks or bottle caps.
And although replacing a known concern is great, the safety
of some of those substitutes is still being researched. We
spoke of Sarah Geller, a senior research and database analyst
at the Environmental Working Group. She said, we don't have
a lot of data about how these materials are used
because the formulas are protected by trade secrets, and even
(06:23):
though cans with newer linings can help you avoid endocrine disruptors,
they may not be good for the environment. Some materials
don't degrade. If you're concerned about contamination from canned foods,
Geller recommends using fresh, frozen, or dried food instead of canned,
But if you simply can't get away from the convenience
of canned foods, absolutely don't eat the food in the can. Finally,
(06:45):
be aware that some compounds, including b p A, have
become such pervasive contaminants in the environment that it's getting
harder to avoid. No matter what your food is packaged in,
Geller said, detectable amounts of b p A may make
it into otherwise b p A free cans from other sources,
including the food itself. To end on a slightly lighter note,
(07:05):
even though food was first canned in metal cans around
eighteen thirteen, it took about forty years for someone to
invent a can opener, and can openers for home use
didn't become popular until the eighteen sixties. Before then, you'd
break out the hammer and chisel. Today's episode was written
(07:26):
by Sean Chavis and produced by Tyler Clang. Brain Stuff
is a production of I Heart Radio's How Stuff Works.
For more on this and lots of other topics that
we put in the can just for you, visit our
home planet, how stuff Works dot com and from our
podcast From my heart radio, visit the iHeart Radio app,
Apple Podcasts, or wherever you listen to your favorite shows.
Welcome to brain Stuff production of I Heart Radio. Hey
brain Stuff, Lauren Vogle Bam. Here, Let's face it, some
canned vegetables are so very different from their fresh forms,
think asparagus, that plenty of kids grow up swearing off
otherwise delicious foods forever. So it's no surprise that canned
foods have a bad rap. But the bad reputation goes
(00:25):
beyond just the food that comes inside those cans. It's
also because of things like the growth of farmers markets
in the last twenty years, and influencers like California's Alice
Waters and Michael Pollen who have encouraged eating locally raised
fresh foods over processed foods, and bp A linings and
scary accounts of the dangers of dented cans told by
well meaning grandparents. So is that bad reputation deserved? First,
(00:50):
Let's back up and talk about canning foods as a whole.
Canning was born out of a search for convenience and efficiency.
A French candy maker and chef Nicholas A. Pear develop
to the process. At the end of the eighteenth century,
Napoleon was offering a huge prize to anyone who could
help him feed his troops. A pair's original process isn't
very different from the canning methods used today. A pair
(01:11):
put food in bottles and jars, covered them with cork
and wax, and processed the jars in boiling water. The
French government paid a pair to make his process public,
and that led to the first recipe book on canning.
The Pair's process spread quickly. Not twenty years later, the
British Navy fed soldiers the first meat, soups and vegetables
that were canned in tin instead of jars. During World
(01:34):
War Two, governments in a number of countries, including the
U S and the UK, promoted home canning. The U
S printed and distributed circulars and opened thousands of canning
centers to help home cooks preserve food grown in home gardens.
Canning became patriotic, supplementing bland and sometimes inadequate rations. In
the nineteen fifties, commercially canned and other packaged foods were
(01:56):
introduced as nutritious, time saving, modern convenient. A popular book,
the can Opener cookbook Buy Food, editor Poppy Cannon promised
readers they could open some cans and create a gourmet
meal without really knowing how to cook. The recipes included
roast canned chicken flombay with black cherries made with a
whole canned chicken. Another meal was made of canned hamburger
(02:18):
patties covered with fried onions and red wine, baked in
a castrole dish for twenty minutes. Canned food was promoted
and seen as better than fresh, especially as industrial agriculture
began to incorporate more modern fertilizers and technologies. The author
of the can Opener cookbook wrote the flavor of fresh
tomatoes was bad and that for real tomato flavor, you
(02:38):
should open a can. Fifty is years later, canned tomatoes
are still an off season go to for tomato lovers
and cooks, and I certainly can't deny the convenience of
a can of beans already cooked and ready to go
into a salad, soup, dip, or whatever other dish, no
long soaking or par boiling required. From a nutrition standpoint,
the canning process today is designed preserve as many nutrients
(03:01):
as possible. Fruits and vegetables for canning are picked at
the peak of their ripeness, as opposed to some produce
picked for fresh sale, which may be underripe to prevent
spoilage during transport from farmed store. Crops destined for canning
are grown close to packing facilities and can be processed
within four hours of harvest. The heat used during canning
does decrease some of the water soluble vitamins in the
(03:23):
finished food, like vitamins B and C, and often salt
and sugar are added during the process. Experts suggest rinsing
canned food to reduce some of the added sugar and salt,
or buying low salt and low sugar products. And of
course that heat also changes the texture of vegetables, regrettably
so in the case of those canned asparagus. But that
heat is a plus when it comes to food safety.
(03:45):
The heat introduces pressure that helps seal the cans, but
it can also kill or deactivate deadly germs. Remember when
we mentioned our grandparents aversions to dented or swollen cans.
Those fears are based in reality. Let's talk about my face.
Its scary condition botuli um. It's caused by a bacterial
toxin so deadly that just a million of a graham
(04:06):
is enough to kill the United States and other countries
even explored botulism as a biological weapon during World War Two.
The bacteria that crete this toxin, clostradian batu linum, are everywhere,
but people associate bauchuli ism with canned foods because the
bacteria only reproduce in low oxygen environments like a poorly
processed can. Today, commercial canned foods go through what's called
(04:29):
a bochu linum cook. This is a high heat cook
that dramatically lowers the chance that any Clustradiu bauchua linum
spores or other organisms that can cause food born illness survive.
For the record, you should discard any can that's puffed
out or swollen that's caused by germs reproducing inside of it,
and it is bad news. Cans that are dented are
usually fine, as long as the dent is not along
(04:51):
the cans scenes. The most recent concern about canned foods, though,
isn't the food at all. It's the cans themselves and
what they're lined with, including b p A. Over the
past two decades, public attention has focused on bp A,
the compound used to make polycarbonate plastics and epoxy resins.
In two thousand and eight, the US government's National Toxicology
(05:13):
Program concluded that there was concern about its effects on
the brains, behavior, and prostate glands of fetuses, infants, and children.
Other studies have linked BPA to cardiovascular disease, obesity, asthma,
and diabetes. B p A exposure is widespread. The Centers
for Disease Control found b p A and of the
urine samples of more than twenty five thousand people aged
(05:35):
six and older. B p A can leach from containers,
including cans, into foods and drinks, and so plastics and
canning manufacturers have worked to develop replacement materials. The Canned
Manufacturers Institute says more than of food cans today are
lined with new b p A free materials such as polyesters, acrylics,
and PVC. Though note that that figure just refers to
(05:59):
food cans. It doesn't include canned drinks or bottle caps.
And although replacing a known concern is great, the safety
of some of those substitutes is still being researched. We
spoke of Sarah Geller, a senior research and database analyst
at the Environmental Working Group. She said, we don't have
a lot of data about how these materials are used
because the formulas are protected by trade secrets, and even
(06:23):
though cans with newer linings can help you avoid endocrine disruptors,
they may not be good for the environment. Some materials
don't degrade. If you're concerned about contamination from canned foods,
Geller recommends using fresh, frozen, or dried food instead of canned,
But if you simply can't get away from the convenience
of canned foods, absolutely don't eat the food in the can. Finally,
(06:45):
be aware that some compounds, including b p A, have
become such pervasive contaminants in the environment that it's getting
harder to avoid. No matter what your food is packaged in,
Geller said, detectable amounts of b p A may make
it into otherwise b p A free cans from other sources,
including the food itself. To end on a slightly lighter note,
(07:05):
even though food was first canned in metal cans around
eighteen thirteen, it took about forty years for someone to
invent a can opener, and can openers for home use
didn't become popular until the eighteen sixties. Before then, you'd
break out the hammer and chisel. Today's episode was written
(07:26):
by Sean Chavis and produced by Tyler Clang. Brain Stuff
is a production of I Heart Radio's How Stuff Works.
For more on this and lots of other topics that
we put in the can just for you, visit our
home planet, how stuff Works dot com and from our
podcast From my heart radio, visit the iHeart Radio app,
Apple Podcasts, or wherever you listen to your favorite shows.
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