Enhanced inactivation of Listeria monocytogenes by nisin in the presence of ethanol

Abstract

Aims: The effect of combinations of nisin and ethanol on the survival of Listeria monocytogenes was investigated. Methods and Results: Killing by nisin was enhanced during simultaneous exposure to ethanol (2-7% v/v). For example, while 10 IU ml-1 nisin reduced viability by 1 log unit in 20 min, a combination of this antimicrobial peptide and 5% ethanol, reduced numbers of surviving cells by 3 log units. Increasing the concentrations of either ethanol (2-7%) or nisin (10-50 IU ml-1) led to increased cell death with synergy being demonstrated for all combinations tested and at a range of temperatures from 5 to 37°C. Conclusions: Ethanol can act synergistically with nisin to reduce the survival of L. monocytogenes. Significance and Impact of the Study: Combinations of ethanol and nisin may be feasible as an effective way of controlling this pathogen in the food processing environment.