By: Dr. Nurul Izzah Khalid

Senior Lecturer

Faculty of Food Science and Technology, UPM

A well-designed sanitation system is fundamental to every hygienic food processing facility. It ensures food safety, extends equipment lifespan, and supports compliance with the Malaysian Food Hygiene Regulations 2009 and international standards such as HACCP, GMP, and ISO 22000. Selecting the right sanitation strategy—whether Cleaning-in-Place (CIP), Cleaning-out-of-Place (COP), or manual cleaning—depends on the type of product, process environment, and equipment design (Figure 1).

Figure 1. The three main sanitation systems in food plant operations: CIP, COP, and Manual Cleaning.

1. Understanding the Core Sanitation Methods

Cleaning-in-Place (CIP)

CIP is an automated system that circulates cleaning and sanitizing solutions through pipes, tanks, and equipment without dismantling them. It is widely used in liquid food industries such as dairy, beverage, and sauce processing, where hygiene, consistency, and time efficiency are critical.

A typical CIP system consists of central tanks for water and detergent, valves and spray balls for circulation, and sensors to monitor temperature, flow, and concentration. Studies conducted at Universiti Putra Malaysia demonstrated that efficient CIP performance depends on optimized cleaning parameters such as NaOH concentration, temperature, and flow velocity. These parameters directly influence the removal kinetics of fouling deposits such as pink guava puree residues, where cleaning efficiency improved significantly under turbulent flow conditions and elevated temperatures (Khalid et al., 2015; Khalid et al., 2016).

The integration of removal kinetics into CIP design enables industries to balance cleaning performance and operational cost. For example, Khalid et al. (2016) proposed an economic cleaning protocol combining optimal flow rate and temperature that achieved complete cleaning while reducing chemical and water consumption.

Cleaning-out-of-Place (COP)

COP involves dismantling equipment components such as filters, fittings, and trays for separate washing in tanks containing detergent or disinfectant. It is widely adopted in meat, seafood, and ready-to-eat food industries, where equipment geometry and heavy organic loads limit the feasibility of CIP.

Recent research on green sanitation practices highlights the potential of integrating alkaline and acidic electrolyzed water (AlEW and AcEW) into COP systems as an effective alternative for removing fat- and protein-based residues, thereby minimizing dependence on conventional chemical detergents (Khalid et al., 2024a; Khalid et al., 2024b). AlEW acts as a mild alkaline cleaner that suspends meat residues, while AcEW functions as an antimicrobial rinse. In trials involving contaminated stainless-steel surfaces, AlEW at 50°C eliminated E. coli cells in the absence of meat residues, demonstrating its potential as a sustainable sanitation solution (Khalid et al., 2024b).

Such approaches are particularly valuable for small- and medium-sized enterprises (SMEs) that often face high costs associated with conventional detergents and wastewater disposal. Implementation of portable electrolysis sanitation units, as proposed by Khalid et al. (2024a), has been shown to lower operating costs and simplify daily cleaning without compromising food safety.

Manual Cleaning

Manual cleaning remains essential in facilities where automation is impractical—such as open conveyors, packaging tables, and work areas. It is common in bakeries, frozen food plants, and small-scale operations. Manual cleaning effectiveness depends on proper tool selection, well-defined standard operating procedures (SOPs), and staff training in chemical handling and hygiene practices.

Incorporating electrolyzed water for manual cleaning offers dual benefits: effective disinfection and reduced exposure to harsh chemicals. For instance, in sanitation trials of SME frozen meat plants, AlEW and AcEW achieved microbiological cleanliness comparable to conventional detergents while minimizing cost and environmental footprint (Khalid et al., 2024a; Khalid et al., 2024b).

Facility layout and surface design—such as smooth finishes, adequate drainage, and good accessibility—also play an important role in improving manual cleaning outcomes (Khalid et al., 2015).

2. Matching Sanitation Systems to Industry Needs

The selection of an appropriate sanitation method depends on the nature of the food product and the type of fouling material. Table 1 summarizes common sanitation methods recommended for different food sectors and their key design considerations.

Table 1. Recommended sanitation methods across selected food sectors

Conclusion

An efficient sanitation system integrates appropriate cleaning methods with an understanding of product characteristics and process conditions. CIP ensures uniform cleaning of closed systems, COP complements it for removable parts, and manual cleaning remains vital for open surfaces. The incorporation of green sanitation solutions, particularly electrolyzed water, represents a forward step toward sustainable hygiene management in Malaysia’s food industries.

At the Faculty of Food Science and Technology (FSTM), Universiti Putra Malaysia, researchers continue to lead advancements in hygienic design and eco-friendly sanitation technologies—bridging academic innovation and industrial application.

References

Khalid, N. I., Nordin, N., Chia, Z. Y., Ab Aziz, N., Nuraini, A. A., Taip, F. S., & Ahmedov, A. (2016). A removal kinetics approach for evaluation of economic cleaning protocols for pink guava puree fouling deposit. Journal of Cleaner Production, 135, 1317–1326. https://doi.org/10.1016/j.jclepro.2016.06.095

Khalid, N. I., Nordin, N., Ab Aziz, N., Ab Aziz, N. A., Taip, F. S., & Anuar, M. S. (2015). Design of a test rig for cleaning studies and evaluation of laboratory-scale experiments using pink guava puree as a fouling deposit model. Journal of Food Process Engineering, 38, 583–593. https://doi.org/10.1111/jfpe.12188

Khalid, N. I., Ab Aziz, N., & Noh, T. U. (2024a). Electrolyzed water for sanitation in meat patties factory: A case study. Journal of Food Engineering, 362, 111757. https://doi.org/10.1016/j.jfoodeng.2023.111757

Khalid, N. I., Sulaiman, N. S., Ab Aziz, N., Taip, F. S., Nor-Khaizura, M. A. R., Sobri, S., & Abd Rahim, M. H. (2024b). Assessing the efficacy of electrolyzed water for sanitizing contaminated stainless-steel surfaces in the meat industry. Journal of Food Engineering, 382, 112199. https://doi.org/10.1016/j.jfoodeng.2024.112199

Date of Input: 04/11/2025 | Updated: 04/11/2025 | nur_jasni