The Proteolytic Activity of Pseudomonas fragi, Pseudomonas taetrolens and Related Species at Low Temperatures

The proteolytic activity of Pseudomonas strains including P. fragi, P. taetrolens, P. aeruginosa, P. chlororaphis, P. fluorescens, P. putida, and P. synxantha was determined at various temperatures from 4°C to 37°C. Out of 43 strains tested, 33 strains grew well at 10°C within 3 days, and all strains except for a P. aeruginosa strain grew at 4°C within 7days. Four P. fragi strains, one P. taetrolens strain, one P. chlororaphis strain, two P. fluorescens strains, and one P. synxantha strain decomposed skimmilk at 10°C within 7 days. Ten P. fragi strains, one P. taetrolens strain, one P. chlororaphis strain, three P. fluorescens strains, and one P. synxantha strain did so at 4°C within 3 weeks. Strains of P. putida did not decompose skimmilk within 3 weeks. The proteolytic activity of P. fragi, P. taetrolens and their related species at low temperatures was discussed from the viewpoint of food hygiene