Hygienic Zoning in Food Manufacturing Factories
The goal of hygienic zoning is to protect products by restricting movement of hazards from low-risk areas of the factory to medium-risk areas and then to high-risk areas over or near exposed product. Many food product contaminations are linked to hazards found in the manufacturing environment. Such hazards did not just miraculously appear in or near the product; they were moved from somewhere else. A well-designed and maintained hygienic zoning program will restrict movement of hazards within the factory.
Included in this article is the explanation of risk and hazard identification as well as barriers and routines to control the movement of hazards. The article also explains the hygienic zoning risk assessment process, seven common means and methods (vectors) for hazard movement, as well as gap identification and documentation. Finally, the article explains the link to engineering projects along with monitoring, verification, and reassessment.
Elements of the Hygienic Zoning Program:
The design of a robust hygienic zoning program is the result of a thorough risk assessment. This risk assessment identifies the following elements:
- Medium-risk areas, low-risk areas, and areas that are uncontrolled
- High-risk areas within lower-risk areas
- Certain areas that a factory may want to quarantine to prevent likely present hazards from moving out, for example, areas processing/storing raw meat or raw agricultural products, areas where metal grinding and drilling occur
- Specific locations where area risks change (area transitions)
- Means and methods (vectors) for hazards to move from uncontrolled areas into higher-risk areas
- Vectors that move identified hazards toward higher-risk areas over or near exposed products
- Gaps between the current state of hygienic zoning protection versus the desired state
Relevant Hazards and Vulnerabilities:
Factories identify the relevant hazards to the product(s) in their Hazard Analysis and Critical Control Points (HACCP) risk assessment. The HACCP program addresses physical, chemical, and microbiological hazards. When it comes to hygienic zoning, factories tend to focus only on the microbiological hazards. Physical and chemical hazards need to be considered as well. Ask yourself, “Of all the identified hazards in the HACCP risk assessment, which could possibly originate in the factory environment?” These will be the focus of the hygienic zoning program.
Just as strengths in programs affecting hygienic zoning can reduce risk, vulnerabilities in these programs can increase risk. Programs affecting hygienic zoning include environmental pathogen testing, master sanitation schedules, preventive maintenance programs for buildings and equipment, and associate training. Strengths and vulnerabilities in such programs should be considered when developing risk-mitigation strategies such as barriers and routines.
Understanding Barriers and Routines:
A hygienic zoning barrier or routine should be designed so that the identified hazards will be prevented from moving past area transition points within the factory. Common routines include:
- Routing unnecessary factory traffic away from risky areas
- Footwear cleaning and disinfection
- Footwear changing or shoe covers
- Changing outerwear like smocks, hairnets, etc.
- Handwashing, hand sanitizing, wearing gloves, etc.
- Disinfection of wheels
- Tool management (cleaning, inspecting, inventorying, storage, etc.)
- Hair removal (lint rolling and/or air showers)
- Utilizing clean plastic pallets in medium-risk areas
- Using temporary physical barriers like movable curtains
- Dedicating tools and rolling equipment to specific areas or tasks
Hygienic zoning barriers tend to fall into two categories: physical and virtual. We should always strive to have physical barriers like walls, vestibules, and doors. Virtual barriers, on the other hand, are on an honor system. Examples of virtual barriers include methods like a plastic chain between stanchions or a painted line on the floor to delineate between two different hygienic zones. When challenged about a painted line on the floor being effective as a barrier, I enjoy replying that a painted line on the road is all that keeps me from having a head-on collision; they can and do work!
A common problem with many hygienic zoning programs is not considering area transitions and the overall impact of performing the routines at the transition points. For example, when too many transitions exist, associates may have to wash their hands several times simply walking from one area of the factory to another. This will appear unreasonable and most likely breed noncompliance. To counter this, consider designating areas as a higher risk than conditions dictate to reduce the need for area transition routines. Keep in mind, a factory should never designate areas as lower risk than actual conditions dictate.
As the team completes the risk assessment, carefully consider the proposed or existing barriers and routines. What are all the options, their costs, their pros and cons? For example:
- Virtual barriers are inexpensive and flexible and can be established almost anywhere.
- Virtual barriers are not effective at stopping dust, humidity, drainage, overspray, etc., from adjoining areas.
- Physical barriers are more difficult to bypass and are consistent.
- Physical barriers are expensive to engineer, install, maintain, and potentially change.
- Factory culture affects compliance with routines and barriers.
The Risk Assessment Overview:
Industrial hygienists are often asked to conduct risk assessments; however, knowing how to conduct these assessments and what to include in them is not always clear. For hygienic zoning, the assessment need not be overly complicated.
The factory needs to utilize a cross-functional team to understand and assess:
- What the medium-risk, low-risk, and uncontrolled areas are
- What the high-risk areas are within the medium areas
- What the relevant hazards are
- What the vectors are
Once these are understood, the team needs to determine the appropriate means of protection (barriers and routines) and the locations where these protections are best applied.
Finally, the factory needs to determine the answers to the following questions: How do we ensure the program is understood? How do we evaluate if the program is, and has been, working as designed? Will changes to the factory consider hygienic zoning?
The Risk Assessment Process:
The risk assessment should follow this sequence:
- A desktop assessment exercise
- A verification activity of the desktop assessment in the examined area of the factory
- Documentation of observations and identified gaps
- Assigning the gaps to specific task owners
- Tracking and verifying task completion following the factory’s established process
The team leader should schedule the areas of the highest risk in the factory as the first area for assessment. Typically, this will be an area with exposed finished product such as a packaging room. Subsequent assessments will be of progressively lower-risk areas until all areas in the factory have been assessed.
Prior to the assessment meeting, the team leader will need to assemble the necessary materials. This should include large engineering diagrams of the area that include all the equipment within the area. Colored markers and sticky notes can be used on the diagrams to capture elements of the vectors described below. The diagram will become a visual aid for the risk assessment. A spreadsheet will need to be created to capture observations, gaps, and required actions.
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