Restaurant Beer Coolers

How I can avoid a bad few employees to drink beer in my restaurant?
sell more than 300 different types of beer. I have found bottles empty beer in the booth, cold barrel, and even the ceiling tile in the bathroom of employees. I closed all refrigerators during business hours, but it is a real pain to always have open when an employee needs something for prep tables. I like that new employees are drinking the beer!
have a personal meeting. tell them what's happening, that is theft and anyone caught will be dismissed and the money will be docked from their pay to compensate for the beer they have stolen. tell you that anyone who knows anything they are obliged to tell you otherwise are helping the thief to commit the crime. show that you are very serious and will not allow employees to steal from you. If you think this is too dramatic (personally I think scare tactics work) may attempt to approach employees about it and see if anyone knows anything? Hope this helps, good luck.
CEF Installs a walk in beer cave cooler in Warner Robins