Kravcheniuk K. Improvement of Surface Cleaning of Milk Industry Production Equipment

The thesis discusses the substantiation of adhesive properties of biofilm formation and degradation on milk industry production equipment and technological parameters under sanitary treatment conditions. Some analytical review of the influence of biofilms formation by bacteria with different morphological and physiological characteristics due to the specific use of production and auxiliary equipment with certain roughness of stainless-steel surface and its behavior after sanitary treatment has been made in the thesis. The main reason of microflora survival on the equipment surfaces after their disinfection in so called «dead zones» (bends, joints, gaskets, valves, cracks, scratches) due to the biofilm formation has been discovered. A framework of conducting the theoretical and experimental study divided into four stages has been given. Some plates made of stainless corrosion-resistant nickelchromium austenitic steel AISI 321 (standard of American institute of steel and alloys) of 30×30 mm size and of thickness 1,2 mm, of the surface roughness Ra=2.68±0.014 mkm, Ra=0.95±0.092, Ra=0.63±0.087, Ra=0.30±0.065, Ra=0.25±0.035, Ra=0.24±0.026 and Ra=0.16±0.018 mkm have been used in the research. The necessary methods and tools for conducting the research have been developed. We have discovered that E. сoli and Е. faecalis. biofilms formation is considerably influenced by both the surface roughness and initial number of bacteria. It was found that under the same conditions E. coli biofilm had lower density comparing to the Е. faecalis biofilm on the stainless-steel surface. The mathematicalstatistical processing of the research results has been conducted by the method of regression-correlation analysis.