Microbial stabilization of grain raw material using silver nanoparicles

Abstract

The paper covers the use of colloidal solutions of silver nanoparticles (SNP) as an antimicrobial agent in the processing of grain raw materials. The purpose of the study was to study the effect of SNP on bacterial and fungal microorganisms, contaminating grains, and to select effective antimicrobial concentrations of SNP solutions. The effect of SNP on the quantitative and qualitative composition of grain microbiota has been studied. The total content of silver particles in the wort obtained from the treated barley grain was monitored by atomic adsorption spectrometry. The working concentrations of the preparation of SNP stabilized with chitosan have been determined, which provided bacteriostatic and fungistatic effects. A method is described for reducing the content of SNP in grain, which has been treated with antimicrobial agent, for its further use in fermentation operations, bakery. Based on the data obtained during the disinfection of wheat grain with SNP, a mathematical model was constructed that reflected the degree of influence of the content of SNP on the change in the number of microorganisms per gram of grain mass. In order to improve the safety of the treated grain, the removal of nanoparticles from the grain mass immediately prior to its use is recommended to be carried out by an alkaline treatment, which prevents colloidal silver from entering the product of processing. To do this, barley samples containing 0.092 g/kg SNP were kept in 0.15% NaOH solution for 1-5 hours, the alkali was drained and the grain washed with water. The 12% barley wort prepared under laboratory conditions was filtered and the silver content was measured. It is shown that the alkaline treatment of barley allows the removal of a significant amount of colloidal silver from the grain mass and prevents its entry into the wort. At the maximum processing time, the silver content in the raw material decreased more than 400 times. Thus, the total silver content of 100 g of grain is less than 0.025×10-3 g, which is below the allowable maximum daily consumption level of silver (0.070×10-3 g).