In the brewing industry, as well as in any other food processing industry, it is vital to develop cleaning and sanitizing processes to enhance and ensure the quality and consistency of finished products. For this reason, brewing equipment developers and brewers themselves must take utmost care when checking the different factors that could reduce or increase the efficiency of cleaning and disinfecting the equipment, including how, when and how often said equipment should be cleaned and disinfected. Factors, such as the chemicals used, their composition, concentration, contact time and quality are of big importance, but also the water quality and its physicochemical composition has to be overviewed.
As an introduction, it is important to clarify the concept of Cleaning-in-place (CIP). Cleaning a specific system could be done manually, where using brushes and different detergents combined with the regular visual inspection would be appropriate. But, the bigger the systems become, the more difficult, dangerous and time consuming the process could be. For this reason, equipment developers, such as ZIPTECH, focus on designing systems where all the necessary cleaning agents and the process equipment are completely connected to each other, thus avoiding the tedious manual work, reducing cleaning time, and replacing it with the usage of pumps, spray balls and even fluid mechanics concepts such as turbulence to ensure a necessary, predetermined degree of cleanliness.
Specifically in a brewery setup, the types of contaminants to be cleaned could be divided in two categories: organic and inorganic compounds. For each one of them, there are cleaning agents designed to efficiently remove them. For the organic materials, alkaline based solution is generally used (most commonly sodium hydroxide based solution) and for inorganic materials an acid based solution (commonly nitric acid based solution). To enhance the performance of these solutions during cleaning processes, it is common to add surfactants, sequestrants (such as EDTA to improve the performance in hard water solutions) and even oxidizing agents (that will help to improve the removing effectiveness of the cleaning agents).
It has to be taken into account that for an efficient cleaning, four factors must be adjusted and supervised: temperature; contact time; mechanical effort applied to surfaces and concentration of the cleaning agent. There must be a balance between all these factors to achieve the degree of cleanliness needed. Then, it is important to determine how to adjust these factors specifically to a system, depending also on the degree of contamination, etc. Important to know that, as a rule of thumb, if one of the parameters (e.g. contact time) is reduced, another parameter has to be increased to balance the cleaning process (e.g. increasing the concentration of the cleaning agent). Also, it has to be taken into account that depending on the nature of the cleaning agent and material that the equipment is built with, there is a range of action for each one of the factors. For example, it is known that alkaline solutions are more effective at high temperatures (around 80ºC), but higher than that could damage stainless steel or also lose effectiveness due to natural heat degradation of the active compound of the solution.
Last but not least, it is important to take into account the role that water quality and composition plays in a CIP process. Water can take up to 95% or more of the bulk of cleaning solutions and it is composed of multiple components (e.g. different ions such as carbonates, sulfates, iron, oxygen, etc.). All of them will interact with the cleaning agents or also represent a bigger challenge for the whole cleaning process to overcome. The harder the used water is, the more inorganic soils deposited and also bigger the reduction in the effectiveness of detergents. The higher the concentration of iron and chlorides, the higher the risks of corrosion to the equipment’s material. Water has to be free of any microbiological contamination due to the regular rinsing steps that take place between cleaning agent’s circulations. There are plenty of interactions that have to be observed, but the water quality parameters could be summarized by the following table, quoted from the article Cleaning in Place (CIP) in Food Processing written by Frank Moerman.
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