The present invention relates to an isolated Lactobacillus paracasei bacterium, deposited as NRRL B-50314, that secretes a bacteriocin. More specifically, the bacteriocin has antibacterial activity against a range of Gram-positive bacteria, including but not limited to Listeria monocytogenes, Staphylococcus aureus, Enterococcus faecalis, and other Lactobacillus species. Additionally, the bacteriocin has antibacterial activity against methicillin resistant Staphylococcus aureus.