A question about fruit flies.

At my bar there have been a few incidents of finding fruit flies in spirits recently. My manager believes that it is fine to filter the fruit flies out of the alcohol and sell it on, but I disagree.

These are mostly liqueurs, but from time to time some harder spirits like whiskeys and vodkas attract them.

What I want to know is if selling them on is fine due to the antiseptic properties of alcohol, or if the alcohol is contaminated and must be poured down the drain and recorded as waste. Any help would be appreciated.