Characteristics of Coliform Bacteria from Olives

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Abstract
Aerobacter, representing 70.5% of the cultures examined, predominated among the coliform bacteria isolated from olives. "Intermediate" cultures constituted the remaining 29.5%. No true Escherichia cultures were found. On the basis of these observations and the results of the survey of the packing plants, fermentation yards, orchard soil and water supplies, it is believed that true Escherichia organisms play a minor role in coliform spoilage of olives. An incubation temp. of 30cC is more nearly optimum for use in characterizing the coliform bacteria which we have studied than 37.5[degree] so commonly used. At 30[degree] it was possible to obtain a much higher correlation for the Voges-Proskauer reaction and the fermentation of glycerol, aesculin, salicin and starch. It is of particular interest that perfect differentiation of A. aerogenes and A. cloacae from olives was obtained by correlation of glycerol, aesculin, salicin and starch fermentation. Differentiation of A. aerogenes and A. cloacae strains from the survey samples by correlation of these characters was almost as clear cut as for the olive cultures. Confirmation of the N availability studies of Mitchell and Levine (1938) was obtained with Aerobacter and "Intermediate" cultures. The Escherichia types did not correlate as well. Explanation of this discrepancy is not possible at present.