Re: Why does mold grow on sandwiches

Hello Cecily Marie,

Your question is a very interesting one. Molds are the growth of certain 
fungi.  There are spores or "little pieces" of fungi that are airborne or 
floating in the air.  You can see them they are too small.  Some of these 
spores will land on the bread of your sandwhich.  Most of them will not 
hurt you.  They do not have a chance to grow.  They grow when they have a 
long time to live with oxygen and water.  Most times this will not happen 
if it is a normal, fresh daily lunch.  If however your sandwhich is left in 
the refrigerator for a long, long time, the oxygen and water in the 
refrigerator will help it grow enough until you see it.  This type of 
growth is called mycelia.  If you see this growth do not eat it.  It may 
give you an upset stomach or worse.  That is how mold grows on sandwhiches!

Your scientific friend,

Darren