February 1929, CHICAGO— Six members of Bugs Moran’s gang of bootleggers were ordered to stand up against a wall, where they were gunned down, probably by members from rival Al Capone’s gang, in what later became known as the St. Valentine’s Day Massacre. The killers were quick and efficient. Their killing efficacy was boosted by the use of gangland’s favorite weapon, the submachine gun.
Killing efficacy also plays an important role in cosmetic preservatives. For reasons of expense, irritation and sensitivity, formulators want to use enough force to get the job done, but no more force than necessary to subdue any dangerous microbes left during the manufacturing process or added during consumer use. Like a gangster with a machine gun, they are sometimes helped by chemicals that are not officially preservatives but can be added to formulations to boost the efficacy of “official” preservatives that are already there.
An “official” preservative is a chemical that has proven antimicrobial activity and has earned a place on lists of preservatives approved for use in various countries or regions. For example, there are 55 chemicals on the list of preservatives which cosmetic products may contain in the European Union.