A NOVEL SYSTEM FOR MONITORING THE INFLUENCE OF OXYGEN-TENSION ON THE MICROFLORA OF GRASS-SILAGE

A novel method was devised to examine the effect of low concentrations of oxygen on microbial populations in grass silage, as reflected by t he aerobic stability of the product. The aim of this system was to sim ulate the micro-aerobic conditions which influence the selective multi plication of the indigenous microflora of grass silage, particularly i n situations where the pathogen Listeria monocytogenes has already est ablished. Ensiled grass in laboratory silos was hushed with a regulate d flow of premixed gases of varying oxygen concentrations at regular i ntervals. The silos could be individually removed periodically in the ensiling process without disturbing the integrity of the system. The e nsiled grass was then examined for microbial content, with specific in terest given to the effect on L. monocytogenes.