Cross-Contamination Control Strategies Part 4: Managing your Hygienic and Environmental Monitoring Zones

Part 3 of our series underscored the importance of plant layout and process control required for minimizing cross-contamination risks within a food production facility.

This blog discusses effective ways of managing hygienic zones and environmental monitoring zones that ensure that cross-contamination risks can be prevented, eliminated, or significantly minimized.

Hygienic Zones vs. Environmental Monitoring Zones

Hygienic zones must not be confused with environmental monitoring zones:

Hygienic zoning is a risk-based concept of separating areas or processes to reduce or eliminate the risk of product contamination and unsanitary conditions. As an example, a typical meat processing site may have the following zones as illustrated:

• The primary pathogen control area (PPCA) here includes the cooked, RTE meat production room. This is a high-risk zone since there are chances that the exposed product could get re-contaminated prior to packing, and there is no further “kill” step to eliminate potential pathogens in a product.

• The basic GMP areas include the material receiving, storage, mixing, and preparation areas prior to the cook (or any other) “kill” step. These are typically low to medium risk zones based on food safety risk assessment.

• The transition areas are places such as locker rooms, warehouses, hallways, and facility entry points. These are generally low to very low risk zones, as they might bear some potential in contaminating the product if not properly maintained.

• The non-production areas include locations like offices that are far away from processing zones. These are very low to negligible risk zones.

Note: Plant layout and flow elements (mentioned in Part 3) can dynamically influence the status of the hygienic zones given above.

Environmental monitoring zones are areas that typically require a microbiological sampling and trending program, which includes swabbing and testing different environmental surfaces to systematically detect any food safety hazards and assess the sanitary condition of the production environment.

As illustrated above, these environmental monitoring zones are typically as follows:

• Zone 4: Non-food contact surfaces or areas outside the food processing areas that are far away from Zones 1 and 2, e.g., locker rooms, hallways, maintenance areas, and break rooms.

• Zone 3: Non-food contact surfaces within a food processing area that are distant from Zone 1 but near to Zone 2, e.g., hand trucks, drains, fork-lifts, and phones.

• Zone 2: Non-food contact surfaces within a food processing area that are near to Zone 1, e.g., equipment housing, and refrigeration units.

• Zone 1: Food-contact surfaces that are in direct or indirect contact with exposed food products, e.g., slicers, conveyor belts, hoppers, peelers, knives, and preparation tables.

Note: Some sites not only monitor microorganisms (e.g., pathogens, spoilage, and indicator organisms), but also other contaminants such as allergens, chemicals, and foreign bodies in the zones mentioned. This allows for the maintenance of a comprehensive environmental monitoring program.

Additionally, at minimum, the FDA requires an Environmental Monitoring Plan for a high risk/high care hygienic zone.

Managing Your Hygienic Zones

Various regulatory authorities (e.g., FDA, FSIS, and EFSA) and global standards (e.g., BRCGS, SQF, and FSSC 22000) mandate food facilities to follow hygienic zoning requirements:

One of the approaches that can be used to reinforce hygienic zoning is the use of color. This may include the color-coding of rooms, areas, or lines, and/or the use of dedicated color-coded equipment for different areas. For example, red tools may be used in the raw meat area, (medium risk zone), and blue tools used in the cooked meat area (high risk zone):

Various regulatory authorities (e.g., FDA, FSIS, and EFSA) and global standards (e.g., BRCGS, SQF, and FSSC 22000) mandate food facilities to follow hygienic zoning requirements:

	During inspections the FDA may conduct environmental sampling in a food manufacturing facility to determine whether that environment contains harmful bacteria, such as Salmonella spp. or Listeria monocytogenes. FDA investigators use sterile sponges or swabs to collect these samples from both food contact surfaces (e.g., slicers, mixers, utensils or conveyors) and non-food contact surfaces (e.g., floors, drains, carts or equipment housing).
	For ready-to-eat meat and poultry products, USDA-FSIS requirements such as 9 CFR part 430 on Listeria Rule recommend Environmental Monitoring Programs as a means to verify sanitation processes, which are crucial for controlling pathogens like Listeria monocytogenes.
	According to an EFSA Journal article, “a well‐designed environmental sampling and testing programme is the most effective strategy to identify contamination sources and detect potentially persistent hazards.”
	BRCGS for Food Safety, Clause 4.11.8: “Risk-based environmental monitoring programmes shall be in place for relevant pathogens or spoilage organisms. At a minimum, these shall include all production areas with open and/or ready-to-eat products.”
	SQF Code for Food Manufacturing, Clause 2.4.8.1: “A risk-based environmental monitoring program shall be in place for all food manufacturing processes and immediate surrounding areas, which impact manufacturing processes ...”
	Section 2.5, FSSC 22000 Additional Requirements, Clause 2.5.7 on Environmental Monitoring (Food Chain Categories BIII, C, I & K) states, in part, that: “The organization shall have in place a risk-based environmental monitoring program for the relevant pathogens, spoilage, and indicator organisms …”

Again, the use of color-coded cleaning tools can help ensure that tools used to clean food contact surfaces (Zone 1) are not confused with those used to clean drains (Zone 3). For example, use blue tools for cleaning the food contact surfaces and black tools for cleaning drains:

Matching color-coded tool storage stations are also recommended for storing tools used for cleaning different zones. These can include color-coded racks and shadow boards:

NOTE: There are no set rules or regulations about which color to use for each zone in a food facility. For tools used in close proximity to the open food product, we recommend choosing a color that clearly contrasts with the food you produce. This will increase the visibility of any related foreign bodies, should the tools be worn, damaged, or inadvertently dropped into the product.

More information about color-coding as a preventive control to manage cross-contamination risks is available in our white paper, Color-Coding Guide.

Future blogs in this series will offer further support related to the following equipment and facility sanitation challenges:

• PART 5: Cross-Contamination Control Strategies: Creating Better Sanitation Programs
• PART 6: Cross-Contamination Control Strategies: Dealing with the Pest Problem, Product Storage, and Transport Sanitation