Zinc oxide nanoparticles help increasing durability of milk

Iranian researchers have studied the antibacterial effect of zinc oxide nanoparticles on various bacteria and added the nanoparticles to milk as antimicrobial agent to investigate the results Results of this research will have applications in various medical industries, agriculture, foodstuff, water disinfection, packaging, pharmaceutics, and food production. Nano-antibiotics are nanomaterials that in addition to having antimicrobial activity increase the effects of antibiotics. Their ability in controlling infection has been confirmed at laboratorial conditions and inside the body. Contrary to many antimicrobial agents that are currently being used in clinics, antimicrobial nanoparticles do not cause undesirable side-effects at milimolar dosage where they have antimicrobial effect. According to Mir Hoseini, one of the researchers of the study, results showed that the antimicrobial effect of zinc oxide was higher on Gram-positive bacterium than on Gram-negative one. Zinc oxide nanoparticles are also able to stop the growth of Escherichia coli and Staphylococcus aureus in milk. However, the toxicity of nanoparticles is higher than the toxicity of the same material in larger scale, even for materials that have relatively low toxicity. Zinc oxide nanoparticles eliminate microorganisms through various mechanisms. These oxide nanoparticles degrade the fat and protein in the bacterium cellular membrane. As a result, the cell content leaks and finally, it leads to the death of bacterium cells. In addition, the production of hydrogen peroxide and Zn+2 ions has been proposed as the key mechanism for the antibacterial effect of zinc oxide nanoparticles. Generally speaking, it can be concluded that zinc oxide nanoparticles showed desirable antimicrobial activity against the microbes existing and being tested in milk and in the growth media. Results of the research have been published in International Journal of Dairy Technology, vol. 66, issue 2, May 2013, pp. 291-295.