728. Lactobacilli in the air of creameries

Abstract

Lactobacilli occur in large numbers in cheese (1), even when the milk used for cheesemaking has been pasteurized (2) and therefore contains very few or no lactobacilli. The lactobacilli in cheese must enter during cheese-making, and a potential source of these organisms is the air of the creamery. Olson & Hammer (3), although not concerned directly with lactobacilli, showed that the numbers of bacteria in the air of dairy plants fluctuated with weather conditions. Naylor & Sharpe(4) found lactobacilli in the air of the Experimental Dairy at the National Institute for Research in Dairying: some strains were identical with others isolated from cheese, but there was frequently no correlation in type of lactobacilli from the air with those from cheese. Thus, ‘cheese types’ were found in the air some months before or after the cheese was made, which seemed to indicate contamination of the air from sources within the dairy. To obtain further information regarding the lactobacillus flora of the air the following investigation was made.