Competition between Salmonella and Pseudomonas species growing in and on agar, as affected by pH, sodium chloride concentration and temperature.

pH/sodium chloride (NaCl) gradient plates were used to investigate competition between Pseudomonas and Salmonella species. At 30 degrees C and at particular NaCl/pH conditions the salmonellae inhibited growth of P. fluorescens and not P. putida. At 20 degrees C P. putida and not P. fluorescens inhibited the salmonellae. The growth of the pure and mixed strains in agar plates with the pH/NaCl conditions was compared by viable counts. Competition in pour plates at 30 degrees C was confirmed. At 20 degrees C, sub-surface growth of the salmonellae inhibited the P. putida. With surface growth this did not occur; the salmonellae was slightly inhibited by the P. putida.