With industry attention riveted on improved food safety, sanitary design of plants is front and center.

A day and a half into the trade show, and the engineer assigned to booth duty clearly was frustrated.

To drum up booth traffic, his employer devised a short multiple-choice quiz on sanitary plant design. Answer five out of six correctly, and visitors were eligible for a free i-Pad drawing. Most of the questions were softballs, the engineer confided, yet only three of the many visitors managed to clear the knowledge bar.

Many of the quiz-takers were owners of small businesses and therefore not intimately involved in the details of hygienic food production, he rationalized. Nonetheless, at a time when ensuring food safety is almost an obsession for many manufacturers and their customers, the gap in understanding sanitary production gives pause.

Sanitary design of both equipment and facilities has received considerable attention in recent years, though the basics of good hygienic design have been documented since the time of Louis Pasteur. In a presentation 60 years ago to industry engineers and sanitarians, Paul Laughlin of the Dried Fruit Association of California allowed that the specifics of maintaining hygienic conditions are complex and specific to the food being processed, but the concerns “are fundamentally the same”: control of microorganisms, pest control, waste removal and a committed effort. “We must deal with individuals who have varying concepts of sanitation,” Laughlin said. “Some have a very high sensibility to hygienic decency, while others may not see the necessity.” His association regularly inspected plants and assigned grades in the areas of machinery and equipment and physical plant conditions, and Laughlin allowed that all processors wanted to avoid the negative publicity and financial loss of a recall, but effectiveness hinged on whether they “merely wish to meet the minimum food law requirements as currently enforced or … have a sincere desire to produce a clean product and provide immaculate plant conditions.”

Al Koch hasn’t preached the gospel of sanitary design quite that long, though the director of engineering-global biscuit for Kraft Foods’ Nabisco division has proselytized for decades the importance of good design. “So often, engineers design an excellent piece of equipment that functions well but is difficult to clean,” bemoaned Koch in a presentation at Food Engineering’s 2011 Food Automation & Manufacturing Conference held last month in Palm Beach, FL. When deficiencies exist in the building itself, managers are stuck with the hand they’re dealt, so Koch focuses on raising awareness of the elements of good equipment design when visiting Kraft plants worldwide. He was part of a group of engineers and microbiologists who formed a working group to improve equipment design after the Peanut Corporation of America-related recalls in 2009. Their efforts culminated in the GMA Principles of Equipment Design for Low Moisture Foods.

Show and tell works better than verbal discourse when counseling young engineers, particularly when language barriers may exist, and Koch has assembled an expansive photo morgue of good and bad sanitary designs. What is possible must be balanced by what is affordable-if bakeries insisted equipment met dairies’ 3A sanitary standards, “we’d be out of business because our costs would not be competitive”-and indoctrination and reeducation is a never-ending process, he says. Even after 30-plus years, Koch himself is learning new techniques. As a result of his conversations with working group peers from Danone, Kraft bakeries are installing gable tops on the tops of production-floor panels to enhance cleanability and eliminate horizontal surfaces where dirt can accumulate.

While industry organizations like GMA and the American Meat Institute are encouraging machine builders to consider sanitation in their equipment designs, “good design often is thwarted by poor installation,” Koch allows. New plant engineers must be taught, and older engineers must be committed to the goal of immaculate conditions.

Walkable ceilings that isolate equipment not needed on the production floor are becoming more common as facility designers prioritize sanitary considerations.

Know the standards

Awareness of sanitary design and its role in remaining in the good graces of customers, regulators and third-party auditors is increasing. Even before passage of the Food Safety Modernization Act in December, manufacturers were being challenged to reconsider procedures and protocols through certification programs under the Global Food Safety Initiative (GFSI), points out Darryl Wernimont, a food & beverage market specialist with POWER Engineers Inc. “The GFSI Guidance Document contains commonly accepted criteria for food safety standards, against which any supplier can be benchmarked,” Wernimont writes. Between 3A, baking’s BISSC standards and the AMI sanitary design principles, he believes manufacturers should have a clear understanding of the most appropriate materials of construction, fit and finishes and equipment cleanability to satisfy customers and inspectors alike.

Others see an industry in transition. A decade after the concept of silver-ion treatment of food contact surfaces was introduced and seemingly rejected, the technology may be starting to catch on. “There’s a growing acceptance and realization that bactericides can be one of the arrows in the quiver for controlling contaminants,” maintains John Durig, global market development director at Sherwin-Williams Protective and Marine Coatings (see related story on page 46). A major brewery demonstrated the efficacy of silver ion in controlling bacterial growth on floors, when added to the top coats of resin floors. The company deployed the technology in November at one of its breweries and plans to use it in 130 additional plants worldwide, according to Durig.

Others are reserving judgment on seamless floors, except in low-traffic locations. “Urethane won out over the epoxies,” says David Dixon, senior director-strategic accounts at Burns & McDonnell, a Kansas City, MO-based engineering design firm. “There are only a few places in a food plant where urethane floors will work. You can’t gouge them, so if there’s a nail on a pallet or wheeled cart traffic,” sanitary design may be breached.

Floors tend to be the dirtiest area of a plant and the most vulnerable to microbiological risk, which is why Dixon advises, “if you have only one dollar to spend, spend it on the floor.” If additional capital is available, he suggests considering a walkable ceiling with insulated metal panels. Worker welfare should be the next focus, with handwashing stations and showers and company-issued clothing.

Air quality is Dixon’s fourth priority, with pressurization and 95 percent filtration trumping other measures. “Wash the ductwork more than once a year,” he adds. Beyond better housekeeping, few options exist to improve air quality, cautions Jim Adler, manager-refrigeration engineering at Hixson Inc., Cincinnati. For example, distributed air should sweep a room, creating “some movement in every area,” he says, but “facility creep” of cobbled-on areas often occurs over time, resulting in dead-air zones.

Something in the air

Air quality is a thorny challenge in refrigerated environments, particularly when heavy washdown ensures floors are covered by a thin film of water and continuous evaporation occurs. A delicate balance is required to minimize condensation and prevent drying out the food. “Any water loss from the food is a yield problem,” Adler points out. “Keep it cool, keep it dry” is the rule of thumb, but infiltration of outside air adds a wild card to relative humidity. Each facility must be evaluated independently to ensure refrigeration is designed and sized appropriately. “You’re going to pay for every cfm, whether you use it or not,” he says.

Air quality is almost an obsession at F&S Produce Inc., a Rosenhayn, NJ operator that processes fresh-cut fruits and vegetables and other refrigerated products. The company currently is adding HEPA filtration in packaging areas. Lou Cooperhouse, an industry expert on chilled foods, recently joined F&S as president and chief operating officer. HEPA filtration is one of four defenses against airborne contaminants, he says, a category that extends beyond microbiological threats to include ethylene gas, allergens, gluten and VOCs from onions and other odorous produce. The company recently received USDA certification to process foods containing meat and poultry. It also achieved Level 3 certification under SQF 2000, one of the GFSI programs.

Proper design of an air handling system is an engineering challenge that absolutely must be met, Cooperhouse says. “Clean room processing is very well recognized by European chilled foods companies,” with proper pressure, air flow, filtration and humidity control elements that must be synchronized. “You can kick a drain cover and send Listeria flying,” he cautions, and it’s a mistake to give air quality short shrift. “The game of shelf life and safety is a game of singles; there are no home runs.”

Batting cleanup at F&S is Doug Nicoll, director of technical services and the microbiologist who drove the SQF certification process. Mold and bacteria are givens, “plus by having people in the rooms, you’re producing aerosols that can contain contaminants,” he says. With HEPA filtration, Nicoll is assured of fewer than 100 particles per cubic meter of air in the packaging zone. To further improve outcomes, a catalytic converter that employs ozone adds a kill step. It replaced an activated carbon filter “that loaded very quickly and deteriorated after a couple of weeks,” says Nicoll. Ozone gas has proved very effective in reducing odors from onions, he adds. Another defense against airborne contaminants is a system in which UV light reacts with titanium dioxide to create free hydroxyl radicals.

Ultraviolet is being considered as a food safety requirement for elements of refrigerated air systems, suggests a white paper by Munters Corp. “Consideration needs to be given to incorporating a UV light section in the condensation control system as a means of meeting this increasingly likely industry requirement,” write experts at the Amesbury, MA desiccant supplier.

As relationships with major retailers and other food companies expand, Nicoll expects to integrate new technologies to maximize product quality and shelf life. Customers are asking about the potential for cross-contamination of allergens through a plant’s air system. “People are raising good questions,” he says, “and we don’t have all the answers.”

Stand-offs on a wire-cut machine for extruding cookie dough and adequate clearance around the the adjoining oven line allow for easy cleaning and are positive examples of sanitary design, according to Kraft’s Al Koch. Source: Kraft Foods Inc.

Evolving standards

Before joining Burns & McDonnell, David Dixon helped design the Kinston, NC pork processing facility of Smithfield Foods. The plant, which opened in 2006, incorporated best-in-class approaches to sanitary design, including highly pressurized air and room-to-room control. Dedicated water supplies and wastewater systems that were isolated from each other and never crossed were installed, adequate space was provided around equipment for 360° access, stainless steel platforms were installed, and minimal contact between floors and materials was a consideration. Still, the needs of production dictate a game of tradeoffs. Fryer placement is an example: Minimizing moisture and heat in the air is necessary for sanitation, but a cooking unit works against that. “If you can put the fryer in another room, then you don’t have to remove the heat, but that’s always a tricky design,” says Dixon.

Similarly, plants used to be designed for linear flow, with wide-open areas between receiving and shipping. Today, zones of separation are the rule, an approach that reduces the risk of cross-contamination but works against efficient product flow. “Companies recognize they must improve food safety,” notes Hixson’s Adler. “They’ve looked at better personal hygiene and gowning. Now they’re moving to the more capital-intensive projects like air handling.”

Greenfield projects provide a blank canvas to incorporate the best approaches to sanitary design. Unfortunately, most professionals must work with the plant they have, and upgrading an older building to meet evolving sanitary standards is difficult, especially for smaller manufacturers that lack the capital access enjoyed by major food companies. Fortunately, there are many opportunities to upgrade sanitary design without major expenditures. The key is to step back, evaluate the existing facility’s strengths and weaknesses, and begin prioritizing.

For more information:

David Dixon, Burns & McDonnell, 630-272-1677, ddixon@burnsmcd.com
Jim Adler, Hixson, 513-241-1230, jadler@hixson-inc.com
Darryl Wernimont, POWER Engineers, 904-318-7186, darryl.wernimont@powereng.com
Greg Baumann, Orkin Inc., 404-888-2783, gbaumann@rollins.com
John Durig, Sherwin-Williams Protective & Marine Coatings, 800-524-5979

Outdoor illumination can contribute to indoor pest problems when light standards are affixed or adjacent to a building’s exterior. A better approach is placement of light fixtures away from the building, so flying insects keep their distance. Source: Orkin Inc.

‘Think like a bug'

Birds, rodents, insects: 20 years ago, pests were dealt with only when a problem manifested itself. Today, food manufacturers are much more proactive in dealing with them, “and that’s a huge shift,” according to Greg Baumann, director of technical services at Atlanta-based Orkin Inc.

The first rule of pest control is to “think like a bug,” says Baumann, “and where they are going to come in.” But too many companies focus their efforts on raw materials storage and fail to consider the many points of entry. He advises clients to start from the outside and work in, beginning with placement of outdoor lighting. “Let’s move the fixtures away from the building and shine the light toward the plant.” Sodium vapor draws flies and moths, but the variety and volume attracted by mercury vapor is much greater. Light in the red spectrum is invisible to flying insects, but “try selling that to the engineering people,” Baumann laughs.

Bakeries often rely on air handling systems to mitigate explosion risks from flour dust, venting the air through a gooseneck on the roof and providing “a nutritious food source for birds, rodents and insects.” A solid sanitation schedule can help mitigate the risk.

Blue-light traps are a popular interior defense, but oftentimes they are placed near a glass door. “Don’t make the light traps visible from the outside,” he advises. Keeping doors and windows closed is obvious, but the same attention is not always paid to loading docks. “Rodents can literally jump onto a loading dock,” Baumann warns. Clear spaces under load levelers are an open invitation to rodents. He suggests administering a pencil test: If an opening is large enough to poke a pencil through, it’s large enough for a rodent to squeeze by.

Aesthetics of cleanable walls and floors

Conventional wisdom holds that a food plant’s ceiling, walls and floor are forever, or at least until the space is taken out of production. But FDA and USDA’s dimmer view of evidence of corrosion could mean premature retirement for many plants, given the prevalence of steel in many wall and floor materials, including reinforced concrete.

Concrete’s advantages have made it a common material for ceilings, walls and floors, but its porosity and poor chemical resistance and tensile strength can result in premature failure in a food-production environment. Rebar or wire mesh usually is added as reinforcement, and once moisture reacts with the steel, oxidation occurs. In years past, manufacturers tried to mitigate the problem with coatings, but many were poorly engineered and improperly applied, leading to blistering, cracking and other evidence of bond failure. Today’s resins are able to deliver a seamless, more durable, washable surface that can extend a plant’s useful life and bear up to the close scrutiny of a customer audit or regulatory inspection, according to John Durig, global market development director for food & beverage at Cleveland-based Sherwin-Williams Protective and Marine Coatings.

Outgasing and moisture-related bond failures soured many food companies to polymer floor and wall coatings in the past, Durig concedes, and coatings unable to handle the food acids and thermal shocks that can cause pinholes and delamination are to be avoided. But today’s breathable resins can overcome those issues. If the right coating is applied, manufacturers like Sherwin-Williams will warranty them for three years and, in some cases, up to five, provided a qualified contractor does the installation. “It’s no longer adhesion but a chemical bond,” he says.

“People are moving to a more cleanable surface, without grout lines,” Durig adds, leading some companies to coat existing wall tiles and acid-brick floors with resin coatings. “There is technology available to create a chemical bond between a glazed tile and our coatings,” he maintains.