Why do bananas spoil faster than honey?

Kim Bruning K.F.Bruning at NOSPAM.stud.biol.ruu.nl
Thu Jun 11 02:16:12 EST 1998


This has to do with osmosis.
Osmosis means that substances dissolved in liquid will try to achieve the
same concentration throughout. Substances with a high concentration in one
spot will want to flow to a spot with a low concentration, and so even
things out.
A Bacteria's cell membrane is semi-permiable, which means that water and
many dissolved substances flow through it unhampered.
This means that many interactions with a bacteria's environment can work
like simple osmosis


Now for the banana and the honey.

A banana has relatively normal sugar levels etc, so bacteria landing on a
banana will have about the same levels of minerals on board as the banana
has. Any residual differences can be compensated by the bacteria dumping
or loading substances which threaten to achieve the wrong concntration
inside.


Honey however, is a different matter. it is very concentrated nectar. so
concentrated, in fact, that one might see it as a solution of water in sugar
;-) .
Now when  bacteria land in honey they have a big problem. The water
concentration in a bacterium is very much higher than in the honey, and it's
sugar level is very much lower. As osmosis takes effect, the water will flow
out of the bacterium, and sugar will try to flow in. The poor bacterium
shrivels up like a raisin, and dies.

People have taken advantage of this effect in the past and even today , when
making jam, salting meat, making concetrates etc.



Neal Bhardwaj heeft geschreven in bericht
<01bd93b1$c2878e00$bd1205d1 at default>...
>I'm a high school student wanting to know why bacteria seem to like bananas
>more than honey? It seems bananas spoil faster. But why? I've got my final
>exam coming up and this was a practice question.
>
>Thanks,
>Sonia
>









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