Knowing Our Food: Storage

Though food nourishes us every day, there is still much that we
can learn about it. At Critical Concrete, we aim to consume as much
local, seasonal food as possible and we have recently started
growing it ourselves in our food forest.
Unfortunately, it is quite common that we as a society eat food
without paying attention to its seasonal availability; it is easy
to be influenced by a globalized system that makes practically any
food available at any time in the year regardless of climate and
the environmental impact. The production of food outside of its
peak season can have 3-10 times the emissions as food imported from
better climates, so it is important to not only support local
farmers, but also to mind the seasonality of fruits and
vegetables.[1] While some imported foods, such as almonds and
avocados, are imported by boat and have a lower footprint than
locally produced options, other more perishable foods are freighted
by air, which creates 50 times the carbon emissions as boat
transportation.[2] Aside from environmental friendliness, seasonal,
local food can be more nutritious and flavorful as it has more time
to ripen before harvest, and supports small farms and sustainable
farming practices.

That being said, choosing local and seasonal produce means
nothing if our food goes bad before we have the chance to eat it.
That means that storing food to extend its lifespan is highly
important. This research grew out of our curiosity to know more
about alternative ways of storing food that are not energy
consuming. However, as we encountered more information, the
research evolved to focus more on food knowledge, with the aim of
informing ourselves and our readers about the needs of our fruits
and vegetables and how we can store and consume them. Our upcoming
articles from this research will delve into the topics long-term
storage, food production, and the use of food scraps, andin this
article, we will discuss how to make use of conventional kitchen
storage to keep food fresh.

Food Waste and the Fridge

Food waste is an immense problem that worsens each year. In
fact, fighting food waste has been determined to be one of the most
urgent solutions to fighting climate change.[3] The production and
disposal of wasted food results in water waste, land waste and
deforestation, and greenhouse gas emissions. Although a tremendous
amount of food waste is the result of industrial food practices, in
Europe 42% of food is thrown out by the consumer, and only one
third of that food wasted consists of inedible residuals (skin,
shells, peels).[4] Regardless of whether climate change can be
tackled through individual actions, consumers can still reduce the
amount of food lost to spoilage in their own homes. Even if it does
not solve environmental issues in and of itself, when we learn
about proper food storage and reduce our waste, we save money and
take the first steps toward better societal food practices.

At first we were inclined to look for alternatives to our usual
house appliances like the fridges, as refrigerants like
chlorofluorocarbons (CFCs) are the main cause of the depletion of
the ozone layer.[5] This led us to a few methods of long-term
storage, which we built as prototypes to evaluate their efficacy in
the climate our research lab is located in. Keep an eye out for our
next article, detailing these methods and their benefits for
different foods and environments.

However, it canât be ignored that storing food in the fridge
and freezer is such common practice, so this article will describe
the ways to reduce food waste in the context of conventional
storage practices. Thus we first have to analyse the way the fridge
is used, to know its strong and weak points and the way it works.
Additionally, it is crucial to understand the process of food decay
and the science behind it. Once it is understood how food decays,
the same principles can be applied everywhere. In order to reach a
balance in the system, minimizing waste and prolonging the life of
food, we must first know the needs of fruits and vegetables and
demystify their storage environments, both artificial and
natural.

Where to store different fruits and
vegetables

Food Decay

Knowledge about everyday storage of fruits and vegetables is
essential. In order to better understand the proper storage of
fresh vegetables and fruits, the first step is to clarify the
biochemical characteristics and processes which occur after
harvesting. This knowledge can help reveal why certain foods become
rotten very fast whereas other foods last for a long time. This
phenomenon is influenced by two factors: the speed of natural
metabolism depending on the specific plant and the way it is
stored.

Enzymes are proteins which serve as catalysts
to chemical changes in living organisms and there are thousands of
different enzymes with varying functions. Enzymes in our food cause
changes to fruit and vegetables which cause them to spoil. In cool
temperatures, these enzymes slow their activity, and they can die
when cooked above 60 degrees.[6]

Aside from enzymes, three other rotting agents can reduce the
life of food. These are mold, which is visible, yeasts, which
convert sugars into alcohol through fermentation, and bacteria,
some of which can poison food.[7] Using this information, we can
determine how to avoid mold and bacteria, and slow down the process
of decay.

Conditions for storage

The best storage method for a given food depends primarily on
three parameters: temperature, humidity and ripening.

Temperature: Cooling down slows down the
metabolic process and thus has an immense effect on preservation.
Nevertheless, there are certain plants, such as bananas, tomatoes,
eggplants or cucumber which are very sensitive to the cold and also
others which lose vitamins and taste.[8] Moreover you should take
into consideration where in the refrigerator to put things. The
middle and the back are usually colder than the other areas of the
fridge.[9] As there is no cooling on the bottom cold air coming
from the middle can warm up and rise up which leads to the
different temperatures levels.[10]

Zones of the fridge and their
temperatures

Humidity: Many fruits and vegetables, such as
cucumbers, leafy greens, carrots and roots, are susceptible to
humidity loss and shriveling.[11] For these, it is important to
ensure a high level of atmospheric humidity. Many refrigerators
have a crisper drawer for vegetables in order to keep a higher
level of humidity. Some vegetables that should definitely be stored
in the crisper drawer are spring onions, celery root, spinach, and
leeks.[12] Otherwise, vegetables that are susceptible to moisture
loss can be wrapped in damp towels and stored in other areas of the
fridge.

Ripening: In basic terms, ripening can divide
produce into two groups: the kind that continues the process of
ripening after the harvest and the kind which abruptly stop
ripening when harvested. This fact depends on the natural plant
hormone ethylene. Ethylene is a gaseous
hydrocarbon (CâHâ) which speeds up the ripening process.[13]
Some fruits and vegetables release ethylene gas in the process of
becoming ripe.[14] Others, by contrast, are sensitive to ethylene
and absorb it.[15] If you do not want to speed up the ripening and
spoiling effect, try to store ethylene-sensitive vegetables apart
from those which release a lot of ethylene.

Ethylene production and sensitivity
in fruits and vegetables

According to their ethylene production, apples, tomatoes,
peaches, apricots, avocados, kiwi, mango and bananas should be
stored apart from other fruits and vegetables.[16] But you can also
make use of this property when you want something to ripen faster.
In that case, you purposefully store high ethylene producers
together with ethylene sensitive ones.[17] When you have green
tomatoes you can store them together with apples in order to get
them to ripen faster.

Referring to proper storage, there are some rules of thumb about
food that should never be stored in the refrigerator. Fruits
sensitive to cold are pineapples, avocados, bananas, mandarins,
mango and melons.[18] Vegetables sensitive to cold are artichokes,
tomatoes, potatoes, eggplants, garlic and onions.[19] Nevertheless,
there are some real divas who cannot really decide whether they
want to be stored in the fridge or in the room. Cucumbers and
zucchinis for example are sensitive to cold but if too warm they
lose humidity and start to shrivel fast.[19] Therefore, they should
be stored in the crisper drawer or in the top part of the
refrigerator, wrapped in a damp towel to avoid cold damage and
humidity loss.[20]

Additional Specific Storage Strategies

With this knowledge of general food storage, we can delve into
more specific ways to increase the lifespan of our fruits and
vegetables. Berries and cherries are susceptible to mold, so they
should not be washed until just before they are eaten.[21] Also,
berries are often quite fragile and should be stored in a single
layer, if possible.[22] Figs are sensitive to humidity, which makes
paper bags good storage containers to absorb their excess moisture,
but they can also be stored on plates in the fridge.[23]

As for vegetables, removing rubber bands from the stems is
always the first step.[24] Radishes, beets, carrots, and turnips,
should be separated from their greens to avoid losing moisture in
the roots.[25] Then, the roots can be stored in an open container
with a wet towel placed on top.[26] Greens are best in closed
containers alongside a damp cloth to keep them from drying.[27]
However, you can save room in the fridge by storing kale, chard,
and collard greens upright in glasses of water on the counter.[28]
Celery and fennel can be stored this way as well.[29] Asparagus is
best stored upright in a water inside the fridge.[30] It should be
noted that using paper bags, reusable containers, glasses, or damp
cloths should make it easy to eliminate the need for any single-use
plastic inside the fridge.

Conclusion

Hopefully, being more cognisant of the needs of fruits and
vegetables can limit food ending up in the trash or compost. Now
that we understand how the chemical processes happening inside
fruits and vegetables cause them to react to different conditions,
we can store it in the right way. We can take advantage of the
different areas inside your fridge, and organize our fridges to
maximize the lifespan of our food. To help adjust to all this new
information, we produced a chart to help understand fruits and
vegetables and store them in the best way possible. Download it,
print it, and put it on the wall in your kitchen!

In our next article about food we will discuss different ways to
store food for longer periods of time and the benefits of each
method. Stay tuned to learn how fruits and vegetables can be
enjoyed past the periods when they are in season, without
forfeiting the nutritional value and flavor of eating seasonal
food.

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