Cleaning In Place System Research Articles

Intelligent clean-in-place (CIP) system in beverage (healthy water) cleaner production

In food and beverage production, maintaining cleanliness is paramount, despite the emphasis placed on it, food safety incidents due to incomplete CIP still occur frequently. This study used the cleaner production of a beverage (healthy water) as a model. An intelligent CIP system employs advanced technologies such as automation, big data, and digital twin to standardize CIP-related data through modeling. Comprehensive management of the CIP process at all levels—from operators to supervisors and managers—is achieved through access control. The digital twin system ensures effective CIP execution by comparing real-time data from automated operations with standard model data. Full traceability and post-event review of CIP activities are realized through CIP order management, while big data analysis quickly identifies problem areas for continuous improvement. This approach ensures the entire CIP process is error-free, fully transparent, traceable, continuously optimized, and conducive to cleaner production.

Multi-length Scale Approach to Investigate Cleaning of Food-Derived Deposits Adhered to Hard Surfaces: Mixtures of Starch, Whey Protein, and Lard

Fouling, the accumulation of undesirable material on manufacturing equipment surfaces, poses a pervasive challenge in industrial processes. In the food industry, the complex interactions among these compounds can give rise to stubborn deposits that deviate from conventional cleaning protocols. In this work, the forces and removal mechanisms of model fouling agents composed of mixtures of starch, whey protein, and lard deposited on solid surfaces of relevant industrial interest (i.e. stainless steel, aluminium, and PTFE) are investigated using a multi-length scale approach, involving milli-manipulation and a lab-simulated Clean-In-Place (CIP) system. The forces involved in the removal process, the types of failure observed when the deposits are subjected to shear stress (adhesive, mixed, or cohesive), and the performance of the CIP system are systematically analysed as a function of the cleaning treatments applied. For stainless steel surfaces, alkaline treatment seems to facilitate the cleaning of lard and starch deposits, while the whey foulant removal tends to be more effective using hot water under the conditions tested. Hot water is effective for stainless steel and PTFE surfaces, reducing the mechanical shear stress required, while the alkaline treatment demonstrated superior efficacy for aluminium surfaces. These findings emphasise the importance of customising cleaning protocols for CIP optimisation.

Rinse model implementation of alkaline detergent in clean‐in‐place process with gradual flow reduction for economy of water and effluent reduction

AbstractDemand for water savings in clean‐in‐place (CIP) process has increased due to the limited offer of this natural resource. Thus, this work investigated the CIP with variable flow in the rinse step in a stainless steel piping system contaminated with alkaline detergent residues compared to CIP with constant flow for rinse water (RW) saving purposes. In addition, the dynamics of the conductivity of the effluent of the CIP system, typically found in dairies, was investigated and water consumption estimated. For this purpose, a CIP prototype was used, which was subjected to cleaning with alkaline detergent (NaOH) at 70°C for 15 min and later rinsed, evaluating the flow reduction effect. The removal of alkaline residue was evaluated under steady state and variable conditions using computer simulation in software Matlab™/Simulink™. The dynamics of alkaline residue removal was modeled using the first order transfer function with dead time (FOPDT) and the gradual flow reduction strategy for rinsing was predicted using the interpolation of the models. The results showed that both strategies were significant for the residues of detergent removal. However, the reduction in spent RW volume was more significant for the variable flow, representing 35% of potable water savings compared to the conventional process with constant flow, what suggests an interesting strategy to reduce the environmental impact caused by the CIP process. Finally, the FOPDT models were effective in predicting the rinse dynamics and determining the time of the process.Practical applicationsStrategies to reduce rinse water consumption and to guarantee food safety are essential. Variable rinse flow can be used in dairy industries to improve economy of water and energy during rinse stage of a CIP process in comparison with the time spent considering the stationary flow process, commonly employed in dairy. In addition, this change is attractive, as it can be made with only adjustments to the control system, not necessarily requiring new equipment.

Influence of cleaning agent reuse on cleaning effectiveness

The Clean-In-Place (CIP) operation use a pump to move a cleaning solution or water over the surfaces of pipelines or alternative food-contact surfaces. In order to improve the overall efficiency of CIP operations, the reuse of cleaning solutions could reduce the demand for water and for cleaning agents. The objective of this study was to investigate the influence of cleaning agent reuse on effectiveness in removal of residues from a food-contact surface during CIP operation. Based on experimental trials conducted with a bench-scale CIP system, more than 99.95% of protein residues were removed by cleaning agent used for the third time. The effectiveness of removal was reduced to approximately 98% when the cleaning agent was used for the fourth and fifth time. The rate constant for removal of the protein residue decreased with the reusing the cleaning agents over three times. When the reused cleaning agents were evaluated in a pilot-scale CIP system, a reduction in the effectiveness of a 0.05% NaOH cleaning agent was detected during the seventh reuse. A 0.5% NaOH cleaning solution maintained cleaning effectiveness through at least seven uses. The pH, electric conductivity, and active alkali concentration of the cleaning solution were monitored, and were found to decrease with the number of uses. The reduced effectiveness of cleaning agents was attributed to the reduced OH- concentration caused by chemical reactions with food residues. Estimation of reduced operating costs associated with the reuse of cleaning solutions was from $7,920 to $ 2,555 per square meter of fouled surface, or about 67%. In general, the outcomes from the project demonstrate that reuse of cleaning solutions can be effective and reduce costs for CIP operations. • After several uses of cleaning solution, the cleaning rate was significantly reduced. • The measurement of chemical properties confirmed the reduction of OH- groups. • The reusing practice would reduce the cost of total cleaning operation by 67%.

ДОСЛІДЖЕННЯ СИСТЕМ ОЧИЩЕННЯ ТОНКОСТІННОГО ФЕРМЕНТЕРУ ПРИ ВИРОБНИЦТВІ МІКРОБІОЛОГІЧНИХ ЗАСОБІВ ЗАХИСТУ РОСЛИН

The peculiarities of microbial plant protection products from pests and diseases allow the use of thin-walled fermenters in their production, in which there is no sterilisation under high pressure. The article is devoted to the development of the cleaning in place system for such fermenters. Experimental studies have been carried out to ensure a pasteurising effect when treating the fermenter with heated sterile water and a nutrient medium concentrate obtained from the sterilizer. Its parameters: its volume, temperature, the time delay have been determined. There is proposed a hardware diagram of the fermentation plant, consisting of an industrial steriliser and a thin-walled fermenter. The cleaning procedure is combined with the main technological process and does not require additional equipment. The production tests have confirmed the cleaning efficiency.

Comparison of flow characteristics in a bench‐scale system with commercial‐scale pipelines: Use of computational fluid dynamics (CFD)

The challenges for scale-up are often encountered in cleaning operations during the interpretation of data from clean-in-place (CIP) research. The objective of this investigation was to design and characterize flow characteristics in a bench-scale system in a manner that evaluates scale-up to a commercial-scale CIP operation. A bench-scale temperature-controlled vessel was designed for evaluation of in-place cleaning, and for development of scale-up parameters. The wall shear stress was selected as the parameter for the comparison, as it is the significant parameter associated with deposit removal. Using the traditional prediction models, the wall shear stress of bench-scale ranged 0.015 to 4.99Pa with impeller speeds from 50 to 900rpm. For the commercial-scale with 0.022m of inside diameter, prediction ranged from 1.43 to 7.90Pa with the mean fluid velocity from 0.72 to 1.67m/s. Computational fluid dynamics (CFD) was used to predict wall shear stress on the surfaces within the bench-scale and commercial-scale systems. The predicted wall shear stress values ranged from 0.016 to 2.42Pa for surfaces within the bench-scale system, and from 1.33 to 7.20Pa for the commercial-scale system. The differences between two calculation methods are attributed to the averaging the magnitude over the whole area and the overestimation of friction coefficients employed in the traditional prediction. The results confirm that CFD provided more reliable wall shear stress estimates for surfaces of interest. The wall shear stress estimates for a bench-scale compare favorably to estimates for a commercial-scale pie section in a CIP system. PRACTICAL APPLICATION: The current investigation demonstrates that the computational fluid dynamics (CFD) simulation provides accurate estimates for the scale-up parameters. Both academic and industrial researchers will benefit from the proposed methodologies to compare the flow properties of the bench-scale and commercial-scale CIP operation that facilitate the practical implementation of the systems.

Predictive Model for the Surface Tension Changes of Chemical Solutions Used in a Clean-in-Place System.

The paper presents the results concerning the influence of concentration and storage time on the equilibrium surface tension of chemical solutions used in a clean-in place (CIP) system. Standard cleaning solutions (prepared under laboratory conditions) and industrial solutions (used in a CIP system in a brewery) were subjected to tests. Solutions from the brewery were collected after being regenerated and changes in equilibrium surface tension were studied during a three-month storage. In the statistical analysis of the solutions, standard deviations were determined in relation to the averages, and a Tukey’s multiple comparison test was performed to determine the effect of dependent variables on the surface tension of solutions. From the results, a nonlinear regression model was developed that provided a mathematical description of the kinetics of changes in the wetting properties of the solutions during their storage. A linear–logarithmic function was adopted to describe the regeneration. Numerical calculations were performed based on the nonlinear least squares method using the Gauss–Newton algorithm. The adequacy of the regression models with respect to the empirical data was verified by the coefficient of determination R and the standard error of estimation Se. The results showed that as the concentration of the substance in the cleaning solution increased, its wetting properties decreased. The same effect was observed with increased storage time as the greatest changes occurred during the first eight weeks. The study also showed that the use of substances to stabilize the cleaning solutions prevented deterioration of their wetting properties, regardless of the concentration of the active substance or storage time.

Mathematical modeling and analysis of the interaction of parameters in the clean-in-place procedure during the pre-rinsing stage

Cleaning procedures in the Clean-in-Place system are the subject of many authors’ research. The paper presents the dependence of the effect of removing milk impurities from the plate heat exchanger on the parameters adopted in the Cleaning in Place procedure at the stage of preliminary rinsing. The study was carried out at the laboratory cleaning station, where the plate heat exchanger contaminated with hot milk was included in the system. The research program was developed according to a 5-level statistical plan, in which process variables were water temperature, flow rate and cleaning process time. The observed variable was the cleanliness of the exchanger plates surface evaluated after the completed process. The obtained results were subjected to statistical analysis. Standard deviations of the cleaning effect with respect to the obtained averages were determined for the central points of the research plan and Tukey’s test of multiple comparisons was performed to identify the significance of individual process variables for the final cleanliness of the exchanger plates. On the basis of the scatter curves, the nature of the influence of individual independent variables on the cleaning effect in the form of partial functions was determined, which formed the basis for the development of a prediction model, in the form of non-linear regression C = f (t,T,vPHE). The developed model is a mathematical description of the process of cleaning out milk deposits from a plate heat exchanger in the Cleaning in Place system. Numerical calculations were carried out on the basis of a non-linear method of the smallest squares using the Gauss-Newton algorithm. Finally, the response area of the dependence between the analyzed variables was determined. The results showed that the cleaning effect depends mainly on the temperature of the cleaning agent and its rate of flow through the cleaned element. On the other hand, the prolongation of plate heat exchanger cleaning time favorably influences the cleaning effect only in interaction with low values of flow rate. Statistical analysis demonstrated that preliminary rinsing of heat exchangers contaminated with milk is best carried out at the temperature of 40÷50°C, at the highest possible flow rate, while decreasing the flow rate, the cleaning time should be extended.

Application of artificial intelligence (AI) in food industry

Artificial intelligence (AI) is the theory and development of computer systems able to perform tasks normally requiring human intelligence. With teeming competition and increasing demand in the food industry, the industry has begun to embrace AI technologies in a bid to maximize profits and explore new ways to reach and serve the consumers. AI has been successfully deployed for applications such as sorting fresh produce, managing supply chain, food safety compliance monitoring, effective cleaning in place systems, anticipating consumer preference and new product development with greater efficiency and savings on time and resources. However, there are challenges to adoption of AI technologies which include cost, cultural changes, expert skill requirements, transparency issues and one track minds. Despite these challenges, researches are on-going on optimized production process using AI but it is important to note that the benefits of AI application in food industry greatly outweigh its challenges.

Inhibitory Effects of Combinations of Chemicals on Escherichia coli, Bacillus cereus, and Staphylococcus aureus Biofilms during the Clean-in-Place Process at an Experimental Dairy Plant

In dairy plants, clean-in-place (CIP) equipment cannot be disassembled, making it difficult to clean the inner surface of pipes. In this study, the inhibitory effects of chemical agents on biofilms formed by three foodborne pathogens, Bacillus cereus, Escherichia coli, and Staphylococcus aureus, was evaluated in a dairy CIP system. The experiment was conducted on a laboratory scale. Each of the three bacteria (200 μL) was inoculated onto stainless steel (SS) chips (25 by 25 mm), and the effect of single cleaning agents was evaluated. Individual treatments with NaClO (30, 50, 100, and 200 ppm), NaOH (0.005, 0.01, 0.05, and 0.1%), citric acid (1, 3, 5, and 7%), and nisin (5, 10, 25, 50, 100, and 200 ppm) were used to clean the SS chip for 10 min. The most effective concentration of each solution was selected for further testing in a commercial plant. Simultaneous cleaning with 200 ppm of NaClO (10 min) and 7% citric acid (10 min) reduced the biofilms of B. cereus, E. coli, and S. aureus by 6.9, 7.0, and 8.0 log CFU/cm2, respectively. Both 7% citric acid and 0.1% NaOH were optimal treatments for E. coli. NaClO and citric acid are approved for use as food additives in the Republic of Korea. Our results revealed that a combined treatment with NaClO and citric acid is the most effective approach for reducing biofilms formed by common foodborne pathogens on CIP equipment. These findings can contribute to the production of safe dairy products.

Staphylococcus aureus and Mesophilic Aerobic Bacteria Quantification in Hygienization Process of Milking Equipment

Background:Milk’s composition is an excellent substrate for microorganism’s multiplication. Presence of Staphylococcus aureus and aerobic mesophilic bacteria are one of the most common problems in dairy farms. On dairy industry’s and milk farms Clean in Place (CIP) system higyenization are commonly used, then the cleaning occurs as a closed process, for better results sanitizans are applied, in order to obtain a safety food. This project aim to evaluate Staphylococcus aureus and aerobic mesophilic bacteria reduction after two milking higyenization process. Materials, Methods & Results:This research was done on a Rio Grande do Sul North Milk farm, with mechanized milking and Clean in Place system for cleaning. For liners and CIP tubes higyenization commercial products as Sodium Hipoclorite 3% and phosphoric acid 11.3% are used for detergency, and peracetic acid 5% for sanitization. Milk bunk tank are higyenized with sodium hypoclorite 3.8% alcalin detergent. After higyenization steps liners, CIP’s water process, bulk milk tank and milk set were collected. At process 1, liners and CIP water were collected after milking, detergency and sanitization that occurred immediately at the detergency’s finish, while process 2 the sanitization was realized 8 h after detergency, before following milking. Cooling milk bulk tank was collected before and after detergency, and milk set after milkings Convencional microbiology were used to count and results in log10 UFC.cm-2. In CIP water’s after process 1 was 3.81 log10 reduction to aerobic mesophilic bacteria (P > 0.05) and reducing 4.51 log10 (P = 0.03). Meanwhile there was no significant reduction for mesophilic aerobic bacteria and S. aureus on the others samples (liners, bulk milk tank and milk set).Discussion: This results show the maintenance of milking machine contamination, and that even bacterial load reduced among hygienization steps this was not significant, suggesting that deteriorate and pathogenic microorganisms can remain on milk produced. Highlights are teat taps of milking machine as the major cause of contamination among cows. The results are worrying because Staphylococcus aureus contamination, once this bacteria causes alimentar diseases, even after higyenization process, which can damage public health that can reflect milk chain economically. Since amount of this microorganism found in milk is already sufficient to synthesize enterotoxins. In addition, resistance to disinfectants is another concern, as it may result in resistance to antimicrobial agents. So reduction of bacteria level among cleaning steps there was no significance, once the products and equipments on dairy and farms act as a constant elimination point of deteriorate and pathogenic microorganisms for the final product, milk. With this studies aim to aprimorate hygienization process on milk chain, in order to obtain a hygienic sanitary good product.

Analysis and modelling of the regeneration process of chemical solutions after brewing equipment cleaning in a Cleaning in Place system based on changes in turbidity

Abstract The study presents the results of an analysis concerning the impact of temperature on the regeneration of the cleaning solution after cleaning the installations of a brewery in a Cleaning in Place system and based on the obtained results optimize the process of chemical solutions regeneration. The solutions were collected from a production plant after the process of cleaning and subjected to 12-h sedimentation. During the sedimentation process in different temperatures, the changes in turbidity were determined, as this represents a purity criterion for chemical solutions. The results were subjected to statistical analysis. The standard deviations of the dispersion in relation to the obtained averages were determined and Tukey's multiple comparisons test was used to identify the significance of the influence of temperature on the purity of the final solution. Based on the obtained results, a non-linear regression model was developed which constituted a mathematical description of the process of sedimentation of chemical solutions after the process of cleaning brewing installations M = f(t,T). The exponential function was assumed to describe the regeneration process. Numerical calculations were carried out based on the nonlinear least squares method using the Gauss-Newton algorithm. Finally, the surface area of the response of the relationship between the time and temperature of sedimentation and the turbidity of solutions was designated. The research results indicated that an appropriate temperature of chemical solutions during their regeneration can significantly influence their final purity degree and the duration of the regeneration process. In the case of sodium hydroxide after cleaning of mash filter, its regeneration is preferably carried out at a temperature below 40 °C, whereas in the case of sodium hydroxide after cleaning of the vessels a temperature of above 50 °C is desirable. Statistical analysis also showed that an acidic solution is best regenerated at 50 °C.

Effect of surface characteristics on cleaning performance for CIP system in food processing

In food processing, insufficient cleaning can result in reduced efficiency, contamination in final product, and energy losses. To optimise widely implemented clean-in-place (CIP) systems, it is critical to understand the influence of the interactions between surfaces, foulant, and chemical agents on the efficiency of the cleaning process. The present work investigates the effect of wall temperature and surface roughness on the surface free energy of stainless steel 316L coupons. Equilibrium contact angles (ECA) of four commonly used liquids, namely ethylene glycol, 1-bromonaphathalene, water, and diiodomethane were measured on the surfaces of interest. Finally, ECAs of liquids were used to quantify surface free energy (SFE) of the solid substrate. Our results show that surface energy is proportional to the roughness and well-prediction of liquids wettability as a function of roughness and temperature. It demonstrates the importance of surface characteristics in determining interfacial energy, and consequently the efficiency of CIP for food engineering.

Optimization of the CIP system enzyme stage for effluent reduction

Milk is one of the main foods and possesses considerable nutritional richness. In this sense, the consumption of industrialized food products has increased significantly and with this it is important to know and improve the processes of hygiene of the industry. Clean in Place (CIP) is a useful technology for cleaning equipment and pipes because it avoids dismantling and is made up of several steps, such as cleaning with alkaline detergent, rinsing, applying acid, rinse, sanitize and rinse. The objective of this work was to evaluate the water consumption and the consequent generation of effluent in the alkaline detergent rinsing stage using constant flow and pulsed flow rates and also to propose an optimal configuration of the pulsed flow to minimize the consumption of water and effluent generated. The tests were conducted in a CIP system prototype and executed based on a central composite planning (CCP) changing the variables amplitude, period and duration of the high part. The response surface technique was used to evaluate the effects of each variable on water consumption. It was verified that there is an optimum condition for the operation of the rinse in pulsed form with amplitude 1.5 L / min, period 138 seconds and duration of the high part of 53 seconds. In addition, it has been found that the rinse with pulsed flow produces an economy of approximately 14.52% in relation to the constant flow operation.

Experimental and Numerical investigation of a Nozzle at different operating conditions for a Clean in Place System

AbstractSelection and optimization of a Clean In Place (CIP) system is a complex process. The CIP nozzles used in the system plays a huge role in the efficiency of the entire system. Therefore, numerical investigations are widely employed by many industrial processes, especially in the hygiene critical industries, such as Food, Beverage and Pharmaceutical industries. An enormous quantities of cleaning agent and water are consumed on a daily basis during their cleaning processes. Finding a reliable and efficient design and operating condition of the cleaning nozzle based on understanding the internal and external flow properties and their optimization is a priority for these industries. This paper presents the comparison between experimental measurement and the numerical prediction of the flow characteristics of a currently available CIP nozzle which are widely used for the industrial cleaning in place application. The flow features are measured experimentally using the optical measurement technique, Phase Doppler Anemometry (PDA) system which is then numerically compared. Computations of the CIP nozzle system were conducted using a finite volume based commercial computational fluid dynamics (CFD) solver, StarCCM+ V12.04. The Eulerian based unsteady multiphase simulation is carried out using different numerical solvers and the best suitable and efficient one is presented here. The achievement of good agreement between the numerical predictions and the experimental results has presented the opportunity to understand the flow behaviour in unsteady state conditions. Based on these studies further optimization will be carried out with the help of some evolutionary algorithms or artificial neural networks.

Design and Simulation System of AHU’s Pre-Filter Washing Machine using Microcontroller

Reducing excess water usage on large scale industries is very influential, both in terms of economics and time. An alternative approach proposed to reduce excess water usage to change the process of manual work into machine workmanship. The pre-filter washing machine is a system that can not only reduce the use of excess water discharge but also streamline the work time. However, the pre-filter washers are different from the usual drum-washing machines. The Pre-filter washing machine is designed to follow the cabinets form with 2 vertical stacking racks, so it can accommodate up to 8 Air Handling Unit’s (AHU’s) Pre-Filter using 2 main valves, 1 water pump, and 1 blower. The washing system designed and simulated by using microcontroller with CIP (Clean In Place) system. This paper expected to save the industrial water usage in terms of Washing AHU’s Pre-Filter.

The impact of clean-in-place parameters on rinse water effectiveness and efficiency

Although Cleaning-in-Place (CIP) is abundantly used throughout the food industry, it is recognized that CIP operations use significant amounts of water and energy. The overall objective of this investigation was to evaluate parameters needed to improve the effectiveness of water use during CIP pre-rinse. A pilot-scale CIP system was operated over a range of Reynolds number (Re) from 16,000 to 260,000, while evaluating the effectiveness of rinse water to remove a reconstituted skim milk residue film from stainless steel pipe surfaces. Rinse water effectiveness was quantified by comparing the protein concentration on the pipe surface after pre-rinse to the initial level. As the Re increased, the effectiveness of rinse step increased, but not in linear proportionality. The efficiency of the rinse water decreased significantly as the volume of rinse water increased. The results of this investigation provide the basis for reducing water and energy requirements during CIP operations.

Application of Nephelometry to Automatic Control of Cleaning Time during Cleaning Process in Clean in Place System

Abstract The article aimed at the evaluation of possible use of nephelometers to monitor changes of turbidity in cleaning solution while cleaning in flow. The results demonstrate the ability to control the duration of cleaning programs. The tests were carried out in a laboratory Clean in Place station and aimed to clean a 10-section plate heat exchanger contaminated by milk. On the basis of the data, the turbidity curves were calculated. On their basis, the kinetic of the cleaning process was revealed. Following turbidity data collection, the heat exchanger plates were also checked for remaining milk contamination. The proposed cleaning steps allow for the possibility to manipulate the cleaning program’s time, and, correspondingly, enable higher energy efficiency in the program. In comparison with the conventional cleaning program currently used in processing plants, our findings demonstrate that the proposed method to monitor turbidity reduces energy consumption by 40 % without decreasing cleanliness.

Poly-optimization of cleaning conditions for pipe systems and plate heat exchangers contaminated with hot milk using the Cleaning In Place method

Devices used in food industry that are connected by pipelines are usually cleaned using Clean In Place method. Such a system of cleaning generates high consumption of energy, water and requires the use of chemical cleaning solutions. In this study, we aimed to activate the physical factors in the process of cleaning and minimize the energy consumption. The variable factors considered within this study were flow velocity, pressure, temperature of the cleaning medium (pure water), and cleaning time. The effects of cleaning efficiency and the energy consumed in the cleaning process were taken as the criteria for the evaluation of the cleaning process in Clean In Place station. For the purpose of optimization, these evaluation criteria were opposed to each other; namely, they sought a high cleaning efficiency with a minimal input of energy. Both functions were based on a set of experimental results using the technique of experimental design. A 5-level experimental design, orthogonal and rotatable, was employed. These equations were used in multi-objective optimization process. A polyoptimal model of cleaning conditions was developed. Results were calculated by using Matlab scripts and showed a set of acceptable solutions on the plane of controllable variables (cleaning factors) because of accepted criteria (energy and cleanliness). The dominated and non-dominated points were appointed. These points described cleaning conditions for which it was possible to obtain a better cleanliness without increasing the amount of energy (the dominated points) and conditions for which we were not able to improve any of the tested criteria (the non-dominated points). Finally, the polyoptimal results defining the favorable effects of a cleaning fluid without the use of chemical agents were determined. The results obtained during this study are important from an ecological aspect of the effectiveness of the Cleaning in Place system and may be applied in real conditions for the development of cleaning programs of the analyzed objects (e.g. in a dairy industry for which these experimental studies have been carried out). The obtained set of optimal solutions constitute a basis for further studies in the aspect of energy consumed and an effectiveness of the cleaning process in Clean In Place system.

Effectiveness of Rinse Water during In-Place Cleaning of Stainless Steel Pipe Lines.

The 1st step of any Clean-In-Place (CIP) operation is a prerinse with water. The purpose of this step is to remove the bulk of food material remaining in the processing lines after production period has ended. It is known that this prerinse step can be a very water intensive process. The objective of this investigation was to measure the influence of CIP parameters (flow characteristics, water temperature, and contact time) on the effectiveness of prerinse water in removing dairy-based deposits from stainless steel pipe surfaces and to compare the rinse effectiveness of unused to reused rinse water. A pilot-scale CIP system was operated to rinse 304 stainless steel pipe sections of 3 different pipe diameters. The velocity of the rinse water was varied from 0.72 to 2.26 m/s. The rinse water temperatures were 22 °C, 45 °C, and 67 °C. The contact times between rinse water and deposited film were 20 and 60 s. Rinse effectiveness was expressed as the ratio of the amount of protein residue removed from the pipe surface during rinsing, as compared to the magnitude of the initial protein deposit. The rinse effectiveness varied from 73.1% to 94.9% for the range of the CIP parameters investigated. High velocities of rinse water provided a higher level of rinse effectiveness. Increasing the rinse water temperature from 23 °C to 45 °C improved rinse effectiveness significantly (P < 0.05). This impact was not significant when the water temperature was increased from 45 °C to 67 °C and at higher rinse water velocities. Similarly, longer contact time provided less improvement in rinse effectiveness at higher temperatures and velocities as compared to lower temperatures and velocities. There were no significant differences in rinse effectiveness when comparing reused and unused water (normal tap water) within the range of velocities evaluated. The rinse steps are important components of the CIP operation and have direct impact on the amounts of water and energy used for the entire processing operation. The efficiency of rinse water can be improved significantly by the selection of appropriate combinations of operating parameters. For example, higher velocities of rinse water (2.26 m/s) provide significant improvements on rinse effectiveness when compared to current commercial practice (1.52 m/s). The careful selection of rinse water temperature and velocity can result in overall reductions in water and energy used for cleaning operations. The reuse of water for a 2nd or 3rd pass provides additional opportunities for reducing water requirements without influencing effectiveness.