While it is a common myth among food preparers, it is not safe to leave meat out if it is soaking in alcoholic beverages. If uncooked meat is left out at room temperatures (regardless of what it's soaking in) it is subject to a number of health risks.
The Myth
The myth that uncooked meat can be left at room temperature if it is soaking in alcohol stems from the misconception that wine, brandy, beer and assorted other alcoholic beverages are able to kill the germs found in raw meat. This is untrue because alcohol, in addition to being a fairly ineffective sanitizer, easily becomes diluted by uncooked meat's various juices. For this reason, alcohol is unable to deter the formation of microbes in uncooked meat. The only thing that can effectively lay waste to those microbes is cooking the meat at a temperature of at least 170 degrees Fahrenheit.
The Proper Method
The best way to keep uncooked meat germ-free is to marinate it in the refrigerator, never at room temperature. Additionally, take care to thoroughly wash any cooking tools or silverware that come into contact with raw meat. It is also strongly advised that you give any storage containers in which the meat was marinating a vigorous cleaning before proceeding to reuse them.
The next time you're preparing meat, remember that while it is okay to marinate uncooked meat in alcoholic beverages, it must be done in the refrigerator. It is extremely unsafe to leave raw meat out at room temperature.
