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Today's Strategies for Hygienic Plant Design

A facility built with hygienic design in mind can help manufacturers meet food safety goals, while an eye on ever-changing industry trends ensures that program stays successful.

Wet processing zones often need more work in eliminating bacteria harbors than dry processing zones, especially in environments with frequent washdowns and clean-in-place programs.
Wet processing zones often need more work in eliminating bacteria harbors than dry processing zones, especially in environments with frequent washdowns and clean-in-place programs.
Big-D Construction

Food safety is the cornerstone of any thriving food processing operation—without it, a company can lose the trust of customers and go out of business faster than it took to build the brand. While the focus of food safety has often been on employees and processing lines where food is manufactured, a bird’s-eye view can reveal the building itself—floors, walls, ceilings, and more—is also crucial to the success or failure of a food safety program.

“Sanitary designs are important because it reduces food safety hazards within the manufacturing environment, making the overall operation safer for food and more manageable for staff,” says Kara Scherer, food safety lead at Dennis Group. “[By definition], sanitary design, or hygienic design, is the incorporation of good manufacturing practices (GMP) into the construction of facilities, equipment, and tools to reduce the likelihood for product contamination, to withstand environmental conditions, and to allow for effective cleaning in a timely manner.”

The food processing industry evolves each year, and with it, new challenges arise for effective hygienic facility design. Here, we’ll explore what foundational strategies still work, and what recent changes are impacting today’s manufacturing plants.

Target zones

The rooms or “zones” where food is processed and packaged have different sanitary design goals from the rest of a plant. Flooring, walls, ceilings, and entrances require special materials and construction plans, while wet processing zones often need more work in eliminating bacteria harbors than dry processing zones, especially in environments with frequent washdowns and clean-in-place programs.

“Hygienic zoning has been a great tool to determine which areas of a facility present the most risk to food products for biological contamination. Manufacturers focus their sanitary design efforts mostly in these high-care spaces because of the greater potential for recontamination of ready-to-eat (RTE) products,” Scherer says.

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“How you segment your plans from a sanitary design perspective is important,” says Mark Redmond, president of Food Plant Engineering. “A dry material producer that doesn’t have water activity in their product has less chance of microbes vs. a wet product, like RTE meals or cold salads. You have a higher risk of listeria and other pathogens, so your design will be different. You have to decide where your most critical zones are going to be and where you want to apply your budget.”

Building materials

Flooring today offers more anti-microbial options than in the past and can be customized depending on what food or beverage is being processed. “Typically, we see urethane for meat facilities and dairy brick or acid-resistant tile (ART) for the fluid milk industry due to the aggressive nature of milk,” says Forrest McNabb, president, national food and beverage, Big-D Construction. “Dairy brick was the go-to material for years, but ART can be a bit more cost-effective than dairy brick and is becoming more common. It took a long time for the industry to consider ART over dairy brick.”

Durable, anti-microbial flooring made of dairy brick has been the industry standard for liquid processing zones, but acid-resistant tile has made inroads in recent years due to its cost-effectiveness.Durable, anti-microbial flooring made of dairy brick has been the industry standard for liquid processing zones, but acid-resistant tile has made inroads in recent years due to its cost-effectiveness. Big-D Construction

Indeed, several experts mention that the food processing industry is slow to change from a hygienic design standpoint because longtime owners tend to stick with what has worked for them in the past. The results of this can sometimes be seen when a design/build firm goes into a facility to retrofit and upgrade the walls in a processing zone.

“Fiberglass reinforced plastic (FRP) used to be dominant in the food and beverage industry. FRP is a good product, but not in a wet environment for processing food because it can harbor bacteria. It’s a very thin material applied over a substrate like wood, or metal framing with sheetrock or plywood over it. Even if applied over a solid surface such as masonry or concrete, there could still be voids based on adhesive and FRP panel joint treatment that allows for migration of moisture behind the panel,” McNabb explains. “I’ve seen some nightmares where we go into a plant for a renovation or upgrade, and we’ll pull FRP off the walls, and you’ll never want to eat the food product they make there again if you could see what’s behind those walls.”

Other construction materials the industry is moving away from for food processing zones include “hollow-core precast slabs of concrete, as these have had some bacteria harbor issues over the years, and concrete masonry units (CMU), which are only utilized in non-process areas unless it has a reliable coating system incorporated in process areas due to CMU’s open-cell structure,” McNabb says.


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Materials like “carbon steel have been widely used for decades for liquid ingredients such as edible oils and sweeteners, but today stainless steel is the standard for sanitary design,” adds Mike Damiano, senior partner at Dennis Group. Stainless steel with smooth surface finishes instead of painted carbon is also becoming more popular in washdown areas.

In zones that are consistently damp, such as poultry processing, precast wall slabs with stainless steel supports built into the slab and anchored from behind hide exposed bolts and other small bacteria harbors from the harsh front-facing environment, and are gaining traction in today’s greenfield projects.

Ceilings in processing zones have also evolved in recent years to expose fewer potential bacteria harbors, while allowing for maintenance and upgrades to be done above the ceiling. “We incorporate the use of sanitary walk-on ceilings frequently on our designs to minimize contamination from overhead structures,” notes Scherer.

Walk-on ceilings over processing zones are being built as interstitial spaces today, where maintenance can happen without risk of contaminating food below.Walk-on ceilings over processing zones are being built as interstitial spaces today, where maintenance can happen without risk of contaminating food below. Dennis Group

McNabb adds, “We’ve seen a lot more focus on taking elements out of the process areas, and putting them into the ceiling or wall cavities, so that when people go to work on plants in the process areas, they’re in an interstitial space, and they’re working from above or behind and not inside the plant.”

Employees and entrances

How employees arrive and leave a plant can be another overlooked element with the potential to add contaminants to food production lines. Close attention to designing those areas with sanitation in mind can help reduce the risk variables.

“There’s been a heightened awareness and focus on where employees come into the plant today. And once they enter the plant, there is no gray area,” McNabb explains. “They are stepping into a GMP area, so the boots and shoes they wear from outside are not allowed in this area—this stops bacteria from the point of entry for employees. The same applies to visitors to a plant. This helps mitigate outside bacteria being introduced into a plant.” 

Redmond adds, “For any employee path to the factory floor, you need to make sure they’re not bringing any contaminants in from the outside. When I look at the layout for a facility, I look at the flows in and out of the room—the people flow, the trash flow, the air flow, the water flows, all those different flows. You’ve got to think about where they’re coming from and where they’re going, and people are a big part of that.”

When assessing the layout for a facility, it’s important to look at the flows in and out of a room—whether the flow of food, people, trash, air, or water.When assessing the layout for a facility, it’s important to look at the flows in and out of a room—whether the flow of food, people, trash, air, or water.Food Plant Engineering

For meat processing plants in particular, the flow from pre-harvesting, where the animals are brought into the facility, can carry contaminants over into the harvesting area if the pre-harvesting area is not up-to-date from a hygienic design standpoint.

“Using sanitary design best practices anywhere food is exposed is important because products are still at risk for chemical and physical hazards,” Scherer says. “For example, if a pre-kill production area has equipment that’s difficult to clean, allergen cross-contact can occur. Additionally, foreign material is more likely to enter the product stream during this phase than post-kill.”

While the food safety focus on employees is often related to hazard analysis and critical control points (HACCP) training and safe food handling practices, McNabb says the ongoing labor shortage and influx of inexperienced workers can pose a risk to the structure of hygienically designed facilities through equipment misuse, creating potential bacteria harbors in the process. “You might have a temporary hire from a short-term labor service, but you don’t know their skill set. They can do some damage in a plant like a forklift accidentally poking holes in walls or hitting columns,” he says. “The more automated the plant, the easier it is to operate these sophisticated facilities, and the better off it’s going to be in maintaining that sanitation, maintenance, and minimizing risk.”

Allergens and equipment placement

The proliferation of food-based allergens over the past two decades has led to a shift in hygienic design by rethinking HVAC effectiveness for many food processing facilities. What used to be the bane of bakery facilities is now an established industry-wide concern, according to Redmond.

“I was at a conference a while ago and I started talking about allergens, and I heard back, ‘We don’t care about allergens. That’s a baking industry problem.’ Today, cross-contamination issues, like gluten, for instance, is an issue for everyone,” Redmond says. “Maybe you could get by in the past where the environment wasn’t as sanitary in terms of dust or air control and filtration, but that bar has been raised across all parts of a processing operation.”

That increased attention to air quality and eliminating potential allergens from a processing environment through filters and HVAC adjustments has a direct effect on the processing lines below, especially with more companies producing multiple SKUs in the same area. “We’ve seen food plants evolve in the U.S. to become more flexible in the products that are produced,” says Rick Burns, manager, process/system engineering at Tetra Pak U.S. and Canada. “With potential allergens such as soy, oat, or almond, the need for flexibility across processing lines without cross-contamination is becoming very important.”

The placement of line equipment and peripheral items such as pumps and motors within a processing zone is also related to the hygienic design of the building around it, according to Tim Rugh, executive director at 3-A Sanitary Standards. “For instance, with a silo tank, you need to be able to access it from different angles, and you need room to get inside and look at it to make sure it has been cleaned properly. Those elements need to be factored into the facility design.”

How employees arrive and leave a plant can be an overlooked element with the potential to carry contaminants to food production zones. Close attention to designing entrances and exits with sanitation in mind can help reduce the risk variables.How employees arrive and leave a plant can be an overlooked element with the potential to carry contaminants to food production zones. Close attention to designing entrances and exits with sanitation in mind can help reduce the risk variables.3-A Sanitary Standards

Software programs such as building information modeling (BIM) or computer-aided design (CAD) might not be directly associated with sanitary design, but those who build food processing facilities say recent upgrades in those software tools allow for deeper detail and improved hygienic design before the project is constructed and the equipment put into place. “The virtual construction world has changed our business,” notes McNabb. “We’ve used modeling software for years, but we have a new level now for modeling. We can see every screw, pipe, bracket, and brace and place them exactly where we want.”

Damiano adds, “3D design tools are making the sanitary design process more efficient because we can better visualize access points to both the facility and the equipment, and ensure the layout is optimized for control points, maintenance, and sanitation.”

Sustainability

Sustainable plant design is a given in today’s environmentally conscious industry, but sustainable materials and strategies have evolved to the point where eco-friendly elements can overlap and help improve hygienic design.

“The means and methods used to reduce waste to landfill, carbon emissions, water use, and embodied carbon can play a role in sanitary design,” says Jacqueline Kull, sustainability lead at Dennis Group. “Waste areas are easily overlooked in facility design but hold the potential to reduce accidental adulteration of food and mitigate contamination from foot traffic. Co-locating large heat-generating devices can reduce carbon and the number of pipe runs, ducts, and duplicative devices that require cleaning. Also, monitoring and maintaining steam traps in a facility will reduce the potential for bacterial buildup and increase the boiler and steam system’s efficiency, reducing carbon and gas consumption by up to 30% for the whole system.”

Owner obstacles

None of the hygienic design strategies mentioned in this story will work if an owner decides that budget is more important than food safety. “Every decision in the food and sanitation world should be a long-term decision,” McNabb says. “No decision regarding sanitation in a food plant should be short-term and solely based on dollars—every decision is a long-term play. You might save yourself $150,000 upfront, but you will cost yourself a million dollars or more down the road if there’s a food safety issue.”

The other side of this is startups and “those new to food manufacturing that tend to lean toward the least expensive solutions without considering the impact it could have on the safety of the product,” Scherer says. Somewhere in the middle, she adds, an owner can prioritize hygienic design even with a tight budget.

“If you’re an owner, you should assess the effectiveness of your current GMP, master sanitation, and preventive maintenance programs,” says Scherer. “If ongoing maintenance will be difficult or costly, you may want to invest more initial capital on sanitary design features. If the full scope of a project is not feasible, separate it into phases so that you can invest in sanitary design, yet expand as funding becomes available.” 

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