This invention is related to controlled release formulations of volatile antimicrobial compounds against pathogens affecting meats, plants, or plant parts or dairy products. Provided are delivery systems in the form of coatings or films, where controlled release of their volatile components in vapor form is triggered by high relative humidity. The volatile component may include, for example volatile antimicrobial liquids including low molecular weight alcohols and/or aldehydes, 1-methylcyclopropene, and/or other volatile fungicides.