The antimicrobial activities of emodin and its derivatives (anthraquinone, alizarin, and alizarin-3-methyliminodiacetic acid) were evaluated using a paper disc diffusion method against foodborne bacteria (Bacillus cereus, Listeria monocytogenes, Staphylococcus intermedius, Salmonella typhimurium and Shigella sonnei). Emodin isolated from C. tora seeds has an antimicrobial activity against Bacillus cereus, followed by alizarin-3-methyliminodiacetic acid ($13.0{pm}2.5mm$) and alizarin ($11.5{pm}1.2mm$). Furthermore, emodin showed the antimicrobial activity against S. sonnei and S. typhimurium. In conclusion, C. tora seed and its active component derivatives are useful for the development of natural products on food supplemental agents and pharmaceuticals.