Characterization of polished rice washing water fermented with milk and its inhibition activity toward tomato bacterial canker causative agent Clavibacter michiganensis subsp. michiganensis

Abstract

Polished rice (seihaku-mai in Japanese) washing water (RWW) exerts a heavy load on gray water treatment. Some farmers ferment RWW with milk and use it for managing healthy plant growth (Fukushima, 2010). In this study, we prepared RWW fermented with cow’s milk (RWWM) and found that it generated flammable gas and protein debris, lowered pH at the early stage of fermentation, and produced lactic acid. RWWM also inhibited the growth of Clavibacter michiganensis subsp. michiganensis (CMM), a causative agent of tomato bacterial canker, but not the growth of Bacillus subtilis, Staphylococcus aureus, or Escherichia coli. Thus, we assumed that lactic acid bacteria are involved in the antibacterial activity of RWWM and that some metabolites in RWWM inhibit the growth of CMM.