Effect of pH and water activity on the growth of Arcobacter sp. in culture

Abstract

Effects of pH and aw on growth of Arcobacter butzleri and A. cryaerophilus in culture media at 30�C were studied. Various weak organic acids were used to achieve target pH, and different humectants were used to control aw. Generally, growth of the bacteria was inhibited at medium pH. Compared to propionic, lactic, malic and ascorbic acids (pH 5.5-5.0), formic, citric and tartaric acids, of the pH range 6.0-5.5, were more inhibitory to both Arcobacter spp. A. cryaerophilus was more susceptible to all acids than A. butzleri. Both strains were extremely sensitive to broth environment, with aw values of <0.980 using NaCl, glycerol and sucrose as humectants. It is suggested that sensitivity to aw and pH may be an important constraint for distribution and survival of Arcobacter spp. in the environment, and particularly in foods