Effect of Carbon Dioxide on the Growth of Pseudomonas fluorescens and Listeria monocytogenes in Aerobic Atmospheres.

The effects of atmospheres containing 20% O and 0 to 80% CO or 30% CO and 0 to 40% O (balance N) on the growth rate and lag phase of Listeria monocytogenes and Pseudomonas fluorescens in buffered nutrient broth at 7.5°C were investigated. Increasing CO concentration lengthened the lag phase and decreased the growth rate of both organisms. CO levels above 20% significantly reduced the growth rate of P. fluorescens and CO levels of 80% significantly reduced the growth rate of L. monocytogenes . Linear and multiple regression analyses were used to describe L. monocytogenes and P. fluorescens growth curves. The values of all regression analyses were greater than 93%. The regression equations indicate that CO inhibits the growth of both P. fluorescens and L. monocytogenes even in the presence of 20% O, However, the effect of CO on P.fluorescens is greater than on L. monocytogenes .