For those antibiotics, we generally just keep them in a fridge with a glass door, without using foil to either block the door or wrap the plates. Ampicillin is a bit light sensitive, but in practice we just throw the plates out after a month anyway. If you are worried, the easiest way is to stick aluminum foil onto the fridge door.

We keep the stake of 3-4 ampicillin agar plates covered in the aluminium foil for storage in fridge, but not more than a month.

You say Ampicillin is a bit light sensitive. Is there anywhere I could find a reference to such information (and maybe also for other antibiotics)?

Thanks a lot for your help.

Best,

-J-

These 2 links may be helpful.

http://bitesizebio.com/9655/antibiotic-stability-keep-your-gunpowder-dry/

http://protocolsonline.com/molecular-biology/antibiotics-used-in-molecular-biology/

But note that they don't say that ampicillin NEEDS to be stored in the dark (which I agree with).

This ampicillin seller is more cautious: http://store.p212121.com/ampicillin-sodium-salt/

If you visit www.merckvetmanual.com/--/penicillins and some other sites, there is mention of ampicillin as sensitive to heat, moisture and light. I cannot comment whether that also is true for ampicillin incorporated in agar media for bacterial cultures. As a precaution, we do assume that ampicillin is light sensitive and use the foil for storage in fridge.

Thank you so much :)

Both of you.

Best,

-J-