Effective Zn-NPs and Conjugates of Nisin and Natamycin Against Food Poisoning Microbes

Abstract

Abstract The study aimed to evaluate the effectiveness of Zn-NPs and its conjugates of Nisin and Natamycin against food poisoning microbes. The results showed the ability of Saccharomyces cerevisiae yeast to produce Zn-NPs, which was shown by the change in color of the zinc acetate solution dissolved in the yeast growth metabolic solution from yellow to yellow. The creamy color is a preliminary indicator of the proven synthesis of Zn-NPs. The characteristics of Zn-NPs were diagnosed by determining the ultraviolet absorbance spectrum of the Zn-NPs solution, which was found to be at a wavelength of 375 nm. X-ray diffraction also examined the presence of Zn-NPs particles in the solution, as it was revealed in the infrared spectroscopy device the presence Zn-NPs particles are in different bundles, and Zn-NPs particles appeared under electron microscope (SEM) in the size range of 49-81 nm and in spherical shape. The results of isolating and diagnosing food poisoning microbes from local yogurt showed the presence of types of food poisoning microbes, including S.aureus, S.pyogenes, L.monocytogens, E.Coli, S. typhimurium, and Candida ssp. By 62, 67, 13, 11 and 50%, respectively. It was found that the minimum inhibitory concentration when using Zn-NPs alone or combined with Nisin or Natamycin against food poisoning microbes contaminating yogurt samples was effective even at low concentrations of 0.39, 0.19, 0.09 against L.monocytogens, S.aureus, and S. typhimurium, E.coli and C. lusitaniae respectively.