Airborne Microbial Contamination in A Winery Bottling Room

Abstract

A filtration air-sampling method was adapted to determine the extent and kinds of airborne microorganisms in a large winery bottling facility. The frequency and distribution of airborne microorganisms were recorded as a series of concentration gradients around various sites in the bottling room. The sources that contributed the most airborne organisms, and thus most likely to cause wine contamination at bottling, were: the filler, especially the bell rubbers and rubber spacers; the floor-drain gutters; the filter-pad drip tray; and the outside air. Several measures taken to reduce microorganisms in the air were studied for effectiveness. Continuous cleaning of the bell rubbers and rubber spacers nearly eliminated the filler as a source of microorganisms. Also effective was regular sanitizing of wine spills, the filter-pad drip tray, and floor-drain gutters. Air filters decreased the microorganism count by 89%. Positive pressure and air curtains reduced the organisms introduced from air outside of the bottling room.

Species of Acetobacter, Lactobacillus, Bacillus, Saccharomyces, Rhodotorula, and Serratia were isolated, and all but the last were found able to grow in California light sweet table wines. Recommendations are made for reducing airborne microorganisms.