ABC’s of Manual Cleaning Part I: Why is it important?

Part I

This blog series will go over the various ins and outs of manual cleaning and why it’s necessary for the safe production of food. It is essential for food processors to understand that the proper selection, use, cleaning, storage, and care of tools employed can prevent or minimize cross-contamination of food from hazards that are of a public health concern, e.g. microorganisms, allergens, and foreign materials.

 Cleaning and sanitation of environmental surfaces (both food-contact or non-food contact) and food production equipment can be a time-consuming operation in food facilities. Nevertheless, the maintenance of sanitary conditions to ensure product safety and quality is a regulatory, industry, and global food safety standard requirement.

The CDC estimates that every year, 1 in 6 people in the U.S. get sick from eating contaminated food. The use of contaminated equipment and utensils is one of the top 5 contributing causes to foodborne illness outbreaks. The key food safety hazards of public health concern are bacterial pathogens, allergens, and extraneous foreign material – and consequently, the cleaning methods and equipment capable of minimizing the risk of these hazards are required.

Industry cleaning methods may range from being process-specific (e.g. clean-in-place [CIP] for cleaning processing pipework and closed vessels]) to the much simpler, process-agnostic manual cleaning involving the use of brushes, scrapers, squeegees, etc.

Automated cleaning isn’t always foolproof

In contrast to manual cleaning, CIP normally involves the automated cleaning of equipment parts, such as the interior of pipes, vessels, or fittings without disassembly. This is generally done by pumping chemicals at a set concentration, temperature, and pH through the system for a controlled period of time at a flow rate that generates turbulence, which provides the mechanical action required as part of the cleaning process in a closed system. Clean-out-of-place (COP) involves disassembly and removal of parts to a remote automated cleaning system.

Once all the cleaning parameters used by these automated systems have been determined and programmed in, cleaning is as easy as pressing a button. However, the biggest limitation of CIP and COP cleaning is that the poor hygienic design of some equipment doesn’t always allow for a thorough using the automated method. Moreover, poorly designed pipework and equipment can result in contaminants getting trapped in narrow, inaccessible, or dead-end zones of the equipment or surfaces being cleaned.

CIP components like spray balls, and the valves, coupling, and sampling ports of CIP cleaned processing pipework also require regular disassembled and manual cleaning, to ensure the on-going efficiency and effectiveness of the CIP clean.

On an important note, the 3-A SSI industry cleaning standard clarifies that if food-contact components of equipment parts are not designed for CIP or other automated methods of cleaning, these parts should be cleaned and sanitized manually.

Key message: Clean before you sanitize

If the food equipment and surfaces aren’t cleaned properly, certain microorganisms may survive and persist by secreting a slimy, extracellular polymeric substance that can enmesh other organisms, nutrients, moisture, and foreign materials to form a biofilm that can firmly attach to a surface.  According to Moorman and Jaykus (2019), manual cleaning is important for surface biofilm removal because “one just can’t sanitize one’s way out of a persistent biofilm problem within a facility. Biofilm eradication, therefore, generally requires equipment teardown, deep-cleaning and sanitation, and a follow-up verification.”1,2

Proper cleaning of equipment and surfaces, therefore, is the first step toward better overall sanitation in food processing plants. Debra Smith, Vikan’s global hygiene specialist, clearly demonstrates the importance of manual cleaning action and the use of cleaning detergent and potable water to significantly reduce surface biofilm load rather than simply immersing a dirty piece in a chemical solution.Sanitization only follows after appropriate cleaning and rinsing of the surface.

In a nutshell, applying detergents and sanitizers alone cannot make a fundamental difference in removing surface biofilms. Manual cleaning will always be required in addition to other cleaning methods because there will always be hard-to-reach places where biofilms can form and can only be effectively be cleaned using hand tools.


Selected References:

  • Moorman, E., & Jaykus, L. A. (2019). Impact of Co-Culturing with Pseudomonas aeruginosa on Listeria monocytogenes Biofilm Physiochemical Properties and Sanitizer Tolerance. In IAFP 2019 Annual Meeting. IAFP
  • Remco (2020). The Role of Manual Cleaning in Biofilm Prevention and Removal. Whitepaper Link:
  • Vikan (2020). Biofilm Demonstration Workshop. Video Link: