What's the ideal temperature for your refrigerator?

In this episode, Christian explains how bacteria spoils food and what temperature your refrigerator should be to slow their progress.

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Episode Transcript

Speaker 1 (00:02):
Welcome to brain stuff from how stuff works. Hey, I'm
Christian Seger, and this is brain stuff. You know when
you reach inside the fridge and your loaf of bread
has turned green and it's covered with white wisps of mold,
or when your tomatoes look like a deflated balloon and
they have spores growing out the top. It's even worse

(00:23):
when those spores start turning black and wrinkly and they
bore into your food and spread out their fungal roots. Obviously,
we're all disgusted by this kind of imagery, as if
we've got some kind of natural revulsion despoiled food, and
we all scream that's gross and probably dangerous. Do not
put it in your mouth. Well, luckily we have refrigerators
which slow the growth of bacteria on our food. Freezers

(00:46):
will do you one better by stopping bacteria completely by
freezing them solid. But we can't freeze everything. Some foods,
like let us, milk or eggs are less than appetizing
after you freeze them, And imagined trying to thaw orange
juice every morning. There's got to be some middle ground
between freezing your food rock solid and leaving it out

(01:07):
to rot. So what's the best temperature to set the
inside of your fridge at? Well, before I answer that,
let's understand spoilage a little bit better. Basically, microscopic organisms
are constantly feasting on our unattended food items. Spoilage bacteria
are fast and inevitable. They're constantly consuming tiny portions of

(01:31):
our food and then spreading their waste all over it.
M M. That's what makes rotten food smell foul and
appear spoiled. And bacteria multiply, sometimes rapidly. As long as
nutrition and water are present, bacteria be making babies. While
there are many methods to detect bacteria, most take several
hours unless you've got an infrared light handy to trace

(01:53):
their biochemical footprints. Even if you can find them, not
all bacteria are necessarily bad. For instance, a certain degree
of bacteria are necessary to prevent illness. Others are used
by food manufacturers to enhance the taste or texture of
their products. Bacteria in beer can control its calorie content.

(02:14):
The holes in Swiss cheese occur when bacteria use lactic
acid to produce bubbles of carbon dioxide gas that leave
holes behind. And of course, there's yogurt that stuff has
bacteria a plenty, containing probiotic enzymes that produce vitamins, enhanced digestion,
and aid our absorption of nutrients. But for the most part,

(02:37):
visible bacteria and mold is a sign that food is
not suitable to eat. Some can even be lethal, like salmonella, E.
Coli and listeria. So what's our best solution? Using our
cold refrigerators to slow bacteria's growth without also freezing our food.
The US Food and Drug Administration recommends that you keep

(02:59):
your refrigerator at or below forty degrees fahrenheit or four
degrees celsius. Anything higher and the food will spoil too quickly.
For the food that you can freeze, you'll want the
temperature to be zero degrees fahrenheit or negative eighteen degrees celsius.
Check both of these periodically with a digital appliance thermometer.

(03:21):
And you want another tip, don't jam your fridge full
of stuff. This prevents the proper air circulation needed and
can hasten spoilage in the freezer. However, feel free to
fill her up. A full freezer actually cools more efficiently.
Check out the Brainstuff channel on YouTube and for more

(03:42):
on this and thousands of other topics. Visit how stuff
works dot com.