ABSTRACT
Antimicrobials are the oldest and widespread defense molecules used by many forms of life from prokaryotes to humans. They include ribosomally synthesized antimicrobial peptides (positively charged +2 to +9) of 12-100 amino acids, mainly produced by bacteria and animals (Jenssen et al. 2006, Li et al. 2012b), and secondary metabolites such as antibiotics, essential oils and polyphenols from bacteria, fungi and plants (Bassole and Juliani 2012, Cotter et al. 2005, Jenssen et al. 2006, Sadaka et al. 2013). Secondary metabolites produced by bacteria, fungi and plants are small molecules. Though they are inessential for the normal growth and development of organisms, they serve as: (1) competitive molecules against other bacteria, fungi, amoebae, insects, and large animals; (2) metal transporting agents; (3) symbiosis agents between microbes and plants, nematodes, insects, and higher animals; (4) pheromones; (5) differentiation effectors; and (6) in some cases, stimulant and/or inhibitor of spore formation or germinations (Demain and Fang 2000). In food applications, antimicrobial compounds have gained considerable attention due to their unique pharmacological
Department of Food Science, 745 Agriculture Mall Drive, PurdueUniversity, West Lafayette, Indiana-47907, USA.
