How old is your culture? Old culture may smell and look difference,
especially after you keep them in the fridge. But contamination may also
produce different odour. If you are not sure about the purity of your
culture then you can run biochemical test or use selective/differential
media, such as SMAC, EMB.
"ROBERT WILLIAMS" <robnic1 at email.msn.com> wrote in message
news:eNTqUiHBAHA.347 at cpmsnbbsa08...
> hi! recently i have bben noticing that when culturing my e. coli cells
> is a distinct order (not the normal smell of the cells). Does anyone know
> it could possibly be contamination or are the cells overgrowing? thanks in