Otimização de processos tecnológicos: redução de recursos econômicos utilizados no método Clean in Place (CIP)

Abstract

Food processing lines, especially the dairy, offer a wide variety of microenvironments in which a variety of microorganisms can multiply and form biofilms. Another challenge for the food industry is the economic and environmental resources associated with sanitation processes. Thus, it is essential to periodically maintain efficient industrial hygiene procedures, with the clean in place (CIP) being the most commonly performed method. In this context, the objective of this work was to evaluate different conditions of the CIP method and to propose an optimization of the conventional process. To carry out this work, a prototype of a stainless steel milk circulation line was used. In this line, test surfaces in different geometries were used: straight stretch, tee, elbow, expansion and reduction, in order to represent common stretches and accessories in the dairy industry. The geometries after cleaning were filled with whole UHT milk and inoculated with previously activated Bacillus cereus cells. After incubation, they were inserted into the milk circulation line for submission to conventional CIP. Right after the conventional CIP process, the geometries were submitted to the swab technique to remove the microbial cells to obtain the final number of adhered cells. In order to optimize the CIP process, pulsed flow configurations were proposed in the sanitization step, in which the variables sanitizing solution concentration and execution time were varied. Finally, the response surface evaluated the influence of the variables under study and the desirability determined the best operating conditions for the CIP for all geometries. The tee geometry was the most challenging in the study, possibly due to the presence of areas of recirculation and stagnation of fluids, which reduce the flow velocity. The variables studied were statistically significant in the decimal reduction of Bacillus cereus adhered to surfaces. The optimal point, determined by desirability, reduced process downtime and minimized energy and sanitizing agent consumption, and was also able to produce the same decimal reductions in elbow, expansion and reduction geometries when compared to CIP conventional, and to increase the decimal reduction in straight stretch geometry. Despite the significant decrease in the presence of microorganisms in the tee geometry, in two cycles, this surface did not meet the recommendations of official bodies or scientific entities in relation to the amount of CFU.cm-2 present on this surface. With this, it is suggested that there is continuity in this line of research so that a configuration is adjusted in order to further optimize the hygiene of this geometry.