Bacterial Film Disintegration with Electrochemically Reduced Water.

The aim of this work was to study the fine structure of bacterial films grown on the inner tube surface of a flow reactor. Using the scanning electron microscopy (SEM) approaches, the detailed biofilm relief was visualized. The action of electrochemically reduced water (ERW) on the biofilm ultrastructure generated by the plankton form of E. coli and/or lacto bacteria was investigated. The treatment with an ERW solution destroyed the biofilm organic polymer matrix and bacterial cells embedded in the matrix.

Disintegration of Bacterial Film by Electrochemically Activated Water Solution.

The structure of bacterial film formed at the inner surface of the recirculation reactor tube, is studied. The surface relief of the biofilm was visualized by scanning electron microscopy. The effect of electrochemically activated water solution on the film formed from planktonic lactobacteria or E. coli was studied. Treatment with electrochemically activated water solution destroys cells and polymeric matrix of the biofilm.

[Microbial stabilization of grain raw material using silver nanoparicles].

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).

The study of the antimicrobial activity of colloidal solutions of silver nanoparticles prepared using food stabilizers.

The bactericidal effect of colloidal solutions of silver nanoparticles based on food stabilizers, gum arabic and chitosan, against bacterial cultures of microorganisms in food production is described. The antibacterial activity of nanotechnology products containing different amounts of stabilizing additives when applied to solid pH-neutral substrates is studied. For its evaluation a method making it possible to take into account the capability of nanoparticles to diffuse in solid media was applied. Minimal inhibitory concentrations of nanoparticles used against Erwinia herbicola, Pseudomonas fluorescens, Bacillus subtilis, Sarcina flava were found. A suggestion was made concerning the influence of the spatial structure of bacteria on the antibacterial activity of colloidal solutions of silver nanoparticles. The data concerning the antibacterial activity and minimal inhibiting concentrations of nanoparticles may be used for development of products suppressing activity of microorganisms hazardous for food production.