Antimicrobials are agents that inhibit the growth of microorganisms or kill them completely. Most commonly known antimicrobials are antibiotics that are used to combat disease-causing bacteria, anti-fungals to combat growth of yeasts and moulds, and compounds used to preserve food and non-food products (e.g. skin care), such as bacteriocins and preservatives. Extensive developments are ongoing to identify novel, effective antimicrobial agents. For food and non-food applications, these include for instance natural antimicrobials produced by bacteria (e.g. bacteriocins and natural ferments) and by plants, for instance essential oils and polyphenols.