Die Bodenkultur - Journal for Land Management, Food and Environment

F. Emerstorfer, W. Kneifel and W. Hein:

The role of plant-based antimicrobials in food and feed production with special regard to silage fermentation


The aim of this study was to determine the minimum inhibitory concentration of plant-based antimicrobials by means of three microbial standard test methods on a range of micro-organisms usually found in silage. Results indicate that hop beta acids and rosin acids were not very effective against Gram-negative bacteria, yeasts and moulds. On the contrary, Gram-positive bacteria could be inhibited at very low concentrations. Interestingly, some representatives of the lactic acid bacteria group showed lower sensitivity against the plant-based antimicrobials than spoilage micro-organisms such as clostridia. This result offers some potential to apply hop beta acids and rosin acids as silage additives, as they are capable of inhibiting bacterial spoilage without negatively affecting the growth of lactic acid bacterial starters. Key words:  Antimicrobials, silage spoilage, hop acids, rosin acids, minimum inhibitory concentration.