Infantaricin, a Bacteriocin Produced by Streptococcus infantarius with Antilisterial Activity

Bacteriocins are antimicrobial peptides (AMPs) considered potential control agents as they are effective against microbial food pathogens even at low concentrations. In this chapter, infantaricin, an AMP produced by Streptococcus infantarius isolated from pozol, a traditional Mexican beverage, was purified using an adsorption–desorption method. Further characterization revealed that the infantaricin was heat resistant (110 °C, 10 min) and showed high antilisterial activity, which was lost following incubation with proteinase K and decreased after trypsin, protease, or α-amylase treatment. The peptide molecular mass was determined with the Tricine-SDS-PAGE protocol and confirmed by ESI-TOF-MS as 5225.53 g/mol. The minimum inhibitory concentration was 4.26 μg/mL for Listeria monocytogenes, indicating the potential of infantaricin in food technology and other biotechnological applications.