In the current study: 1. Soybean protein isolate (SPI), and chickpea protein isolate (CPI) were subjected to esterification to increase their net positive charges and the antimicrobial activity of the resultant proteins. Both modified proteins were quantitatively evaluated and compared to the corresponding native proteins. 2. The antibacterial action of native and esterified proteins isolated from soybean and chickpea were tested in controlling the growth of the bacteria contaminating raw milk as kept at room temperature (25-30?C) for 24 h and maintaining the physicochemical quality of the milk. 3. There is currently little or no information regarding the in vivo toxicology of chemically modified proteins, particularly the methylated ones. Methylated soybean proteins have been proved efficient as antimicrobial agents and it is essential to confirm their safety before any wide productive applications in food preservation or counteracting human and plant viruses. Therefore, the current study investigated the possible toxicity impact of administering such proteins to Wistar Albino rats in one acute dose or repeated subacute doses for 28 days.