An emerging consensus on how best to minimize contamination risks in food plants is adding clarity to design objectives.

The 21st century’s first decade saw an unprecedented focus on improving the safety of processed foods and the conditions under which they are produced. Billions of dollars in collective spending by food and beverage companies helped reduce the likelihood unsanitary production conditions would trigger a recall or legal action.

Much of the early investment was scattershot, however. “Sanitary conditions” is a relative term, and the expectations of customers were not well communicated. In recent years, uncertainty is giving way to clear guidelines and expectations. International standards are beginning to emerge, giving food companies a framework for assessing the sanitary design of their facilities and equipment and identifying areas for improvement.

The Pasteurized Milk Ordinance and 3A sanitary standard long have served the dairy segment, but until sanitary-design task forces organized by the American Meat Institute developed design principles for equipment in 2003 and facilities in 2004, expectations for non-dairy foods were unclear. Modification of the meat and poultry guidelines for dry product production by the Grocery Manufacturers Association (GMA) has added more clarity, as have hygienic standards stipulated by authorities in Japan and the European Union.

Standards and guidelines are starting points. As engineers reconsider construction approaches with an eye toward sanitary outcomes, they sometimes find deficiencies in accepted designs. For example, hermetically sealed hollow tubing meets GMA sanitary principles, yet John Brink of POWER Engineers in Atlanta was surprised to find water inside square, welded tubing being removed from a food client’s platform. “There’s not a maintenance man out there who won’t put a hole in a square tube if he has to mount something,” observes Brink, who believes such a hole provided a channel for the water. Henceforth, all the support columns for platforms, conveyors and tanks that he engineers will be round. “I have found a new religion,” proclaims Brink.

Hygienic expectations are increasing, however, and the food safety audits performed by groups such as SQF and BRC under the Global Food Safety Initiative are providing a rude shock to companies that have not made the kinds of upgrades necessary to meet rising expectations. When the US Food and Drug Administration begins inspections under the Food Safety Modernization Act, line shutdowns are likely. Even without regulatory action, manufacturers that don’t measure up face ultimatums from retail and foodservice clients as well as other food companies to either meet the higher hurdles or lose their business.

For the most part, the 5,200 new plants and major expansions completed in the last decade were designed with cleanability and contamination control in mind. Machinery suppliers have reassessed and often reengineered their equipment to simplify cleaning and sanitizing. And food manufacturers and equipment vendors have borrowed best-of-class concepts from around the world and applied them to their own operations. Continuous improvement is the rule in sanitary design, and maintaining sanitary conditions is an ongoing challenge. Each upgrade serves the goal of better food safety but often lays bare vulnerabilities not previously considered. An example is the stainless steel electric motor.

A curiosity a decade ago, stainless motors have become standard power sources in raw food environments, such as poultry processing. But no matter how bright their surfaces gleam after a high-pressure washdown, these motors harbor a dirty little secret. Contaminants build up under endbells and form a nutrient-rich biofilm on fan blades and interior surfaces. When the fan whirls, microbes in the biofilm become airborne, spreading an unseen hazard throughout the work zone.

When John Oleson of Stainless Motors Inc. pointed out the problem on motors sent to his machine shop for servicing, managers of the food company that owned them were aghast. The experience triggered some creative thinking, resulting in a design change that his firm expects to incorporate in all of its motors in August.

Oleson, who serves as chief engineer of his Rio Rancho, NM firm, incorporates a sprayball under the shroud, with a water inlet port providing a CIP-like cleaning system to flush out any contaminants. Motor fans are now crevice free and polished stainless, with a stainless nut blind-tapped to eliminate crevices when attaching the fan to the shaft. A dry endbell system also is available, though food engineers who have reviewed Oleson’s design predict the overwhelming demand will be for the sprayball-equipped endbell.

A conventional motor could be disassembled and cleaned, he allows, “but nobody does that, and removing the shroud would pose a safety issue. It’s an open secret that there’s debris back there, but no one has come up with a way to clean it efficiently until now. It’s a problem that’s out of sight, out of mind.”

Standardized solutions

Hygienic design and cleanability now are built into many manufacturers’ RFPs, but inconsistent and contradictory requirements from one company’s specs to another’s adds cost without necessarily improving results. Standardized solutions can save engineering costs for suppliers and procurement costs for manufacturers. Air handling systems are an area where this is playing out.

HVAC and refrigeration systems have received special attention in recent years. Control of moisture levels and airborne pollutants is critical for food safety. Ten years ago, a best practice was to circulate incoming air from the area requiring the highest level of hygiene to the dirtiest area. Today, each processing area is an entity unto itself, with positive pressure to keep out contaminants and control allergens.

Joe Bove of the architectural engineering firm Stellar credits the efforts of engineers at Sara Lee and Nestlé for creating standardized classifications for air handling systems. Those food companies worked closely with major suppliers of compressors, condensers and other refrigeration and air-handling equipment to develop standard packages for different processing environments. By specifying a particular hygienic classification, food manufacturers can hold down system costs, says Bove.

“Leading-edge food manufacturers are the drivers in sanitary design improvements,” adds the vice president-design engineering at Jacksonville, FL-based Stellar. “Nestlé has the bench depth and strength to seek out and encourage the best designs.” Best practices in sanitary construction and equipment design are reflected in the plants being built in China, India and elsewhere, as international manufacturers try to anticipate global food safety expectations in decades to come.

Independent temperature and humidity control within a given pressurized zone requires a higher degree of engineering, but companies are making the necessary investments, according to Mike Parsey, manager of the food processing group at Shambaugh & Son LP, Fort Wayne, IN. Companies also are upgrading system components, with stainless steel often the material of choice. Air ducts provide potential harborage for viruses, bacteria and other contaminants, and Parsey says some North American processors are replacing galvanized steel with cloth ducts, a popular option in Europe. “There are some velocity issues,” he allows, but if a contamination issue surfaces, “you can send the ducts to a laundry service.”

While design concepts freely move from continent to continent, meshing them with domestic approaches can be a problem. Michael Rach, director-EPC for Gray Construction in Lexington, KY, cites recent projects that had to be designed to European requirements, such as providing a drain for every three square meters of flooring, or about one drain every 10 feet. This is contrary to the growing practice in US dry processing, such as baking, where engineers want to minimize the number of drains. Similarly, Europeans demand white floor and wall finishes, while American manufacturers are gravitating toward more color coding to distinguish between raw, finished and in-process areas.

Regardless of color, change is occurring in flooring fundamentals as well. Instead of a monolithic coating over a cement base, some food companies are turning to reinforcement systems and different concrete mixes to minimize the number of joints. The objective is to minimize harborage points, says Gray’s Randolph Wilson, director-process engineering. While monolithic toppings initially address the harborage issue, the cracks and delamination that may occur over time can undermine sanitation.

Northeast Foods’ bun plant in Clayton, NC, built in 2011, exemplifies this shift (see “Plant of the Year—Automatic Rolls of North Carolina,” Food Engineering, April 2012). At the recommendation of its A/E firm, A M King Construction, Northeast selected high-density cement with a polished veneer that added some cost but eliminated the need for a top coat and reduced the ratio of floor joints to one per 15,000 sq. ft., compared to one per 1,000 sq. ft. in a conventional cement floor. A shrinkage-compensating component in the concrete is the key, according to Greg Fricks, principal in the Fricks Co., the Fort Worth, TX  subcontractor that poured the floor. A trap-rock finish and polishing process help make the concrete denser and more abrasion resistant. The floor also results in less dust. “Dusting [in a conventional floor] comes from the floor because the floor is wearing out,” Fricks explains.

The versatile IMP

Insulated metal panels (IMP) have become the material of choice for walls in new construction. “The use of IMPs in both structural and nonstructural applications has been growing,” notes The Austin Co.’s Greg Crnkovich, director of planning for food & beverage projects. In some cases, the foam insulation is superfluous; washability is the attraction, particularly if the cladding is stainless steel. Compared to fiberglass or baked-on enamel surfaces, stainless IMP represents a significant hygienic upgrade.

Set horizontally, the panels can serve as the floor of a walkable ceiling, adds Crnkovich, and North American food manufacturers have embraced the walkable ceiling. “We have had some form of walkable ceiling in our last six food projects,” Gray’s Rach says. Besides isolating sensitive areas from utility piping and equipment that don’t necessarily need to be in the processing area, walkable ceilings shrink the production envelope. An extreme example of this strategy is aseptic processing, where sterility is critical to maintain and impossible to deliver in a large, open environment.

“A walkable ceiling is a fairly expensive system, but it allows you to use a rather inexpensive building and put a box in a box,” says Crnkovich. It also can lower other roofing costs by permitting the use of bar joists and girders instead of a double-T roof.

Another proponent of walkable ceilings is David Dixon, who believes misconceptions about their cost/benefit need to be addressed. “Creating interstitial space makes the production room vastly cleaner, and there’s the argument that it saves on construction cost and downtime,” says Dixon, who recently formed David C. Dixon LLC, a food construction consultancy that pools experts in cost analysis and project justification to help shape construction projects. “The great, big, open room is going away,” he believes. “If you have a 30-ft. ceiling, you’re never going to clean it.”

Corridors that link processing zones and house utility runs are an alternative, but “the discussion starts with interstitials,” says Shambaugh’s Parsey. The opposite is true in Europe and Asia, however. Tall ceilings and enclosed production space that “never let the food see the light of day” are the preference in those regions, he says. Ultimately, that approach costs more than the walkable ceiling.

Plastic or wood?

Consulting engineers give high marks to machine builders in making their equipment easier to clean and less likely to pose contamination threats to products. Atlanta-based Crnkovich cites the example of a liquid filling system that incorporates a retractable trough that swings into place under the filler valves to catch discharged cleaning solvents during CIP cycles, sanitizing the valves without requiring disassembly. In dry environments, Crnkovich applauds the growing use of back-mounted vacuums to remove waste, though care must be taken to prevent the vacuums from becoming bacteria incubators. “It costs less money to sweep and vacuum materials up than to put them down the drain,” he points out.

Hygiene considerations also are driving increased use of plastic pallets, though higher costs and lost pallets often limit plastic to in-plant use, allows Rex Lowe, president of Intelligent Global Pooling Systems (IGPS), Orlando, FL. His firm tackles the loss issue by leasing plastic pallets to food companies and using tracking technology to tip off law enforcement when a theft ring is uncovered.

In random tests commissioned by IGPS of bacterial loads on wood pallets, high counts of Listeria and other bacteria were found in five of 30 pallets tested in Portland, ME and 15 of 30 in Philadelphia, bolstering the argument for keeping wood pallets out of production areas. Insect infestation is another issue, and chemical treatments can cause additional problems. According to Lowe, a pharmaceutical company experienced seven recalls in 2010 after its OTC medication acquired a musty odor from a byproduct of a chemical cleaner for wood pallets. With stricter food safety audits, he expects conversion to plastic will accelerate, though the wood pallet infrastructure is entrenched. “In the US alone, there are 2 billion wooden pallets available,” says Lowe.

Good manufacturing practices dictate that doorways be kept closed when not in use, though warmer weather can derail best intentions. Loading docks are vulnerable, particularly if there are ledges and other roosts over the doors, cautions Patricia Hottel, technical director of McCloud Services, a pest solutions affiliate of Copesan in Hoffman Estates, IL. Even when doors are closed with automatic timers, shipping and receiving is vulnerable if there are ill-fitting bumper guards and deteriorated door seals. Hottel recommends thick brushes instead of rubber seals around doors. “They’re less brittle and tend to hold up longer,” she says.

Even a corrugated metal building can provide a sanitary environment when new, Hottel continues, but voids and gaps surface over time. Ongoing maintenance and upgrades are necessary, but not all food companies make the investment. The problem is most acute at small to midsized copackers, according to Paul Hudale of Nutec Group, York, PA. Vegetation surrounding the building, loading docks without seals and “birds flying around in the summer” are not unusual sights when Hudale reviews a facility’s sanitary compliance to standards such as BRC and SQF. Many older food plants are beyond redemption: Sanitary upgrades in some cases would cost almost as much as a new facility. With foodservice, retail and business-to-business customers setting deadlines for meeting new sanitation standards, Hudale predicts those owners will either have to move to a newer facility or exit the business.

If new construction is an option, A/E professionals advise focusing on more stringent personnel hygiene since people are a major source of plant contamination. Consequently, changing areas to keep street cloths and footwear out of the production area will soon be essential. Sloped locker tops and bans on food storage in lockers are just a start. “Issuing company-supplied boots and the cleaning of boots are among the early discussions we have with clients,” says Dixon. In some cases, companies are aiming cameras at washroom sinks and reprimanding workers who fail to scrub up after using the facilities.

About 167,000 US food facilities are registered with FDA. Older plants face an uncertain future, with many likely to be shuttered in the coming years. Even facilities of recent vintage have to meet higher expectations for sanitary design or risk losing key customers. Sanitary design, like food safety, is not a competitive issue, but it is shaping up as a prerequisite to compete in the manufacture of food. 

For more information:

Greg Crnkovich, The Austin Co., 404-564-3950

David Dixon, David C. Dixon LLC, 630-272-1677,

Greg Fricks, Fricks Co., 817-560-8281

Randolph Wilson, Gray Construction, 859-281-5000

Rex Lowe, Intelligent Global Pooling Systems, 321-281-9200

Patricia Hottel, McCloud Services, 847-944-9528,

Paul Hudale, Nutec Group, 717-434-1532,

John Brink, POWER Engineers, 678-966-4400,

Mike Parsey, Shambaugh & Son, 260-487-7777

John Oleson, Stainless Motors Inc., 505-867-0224,

Joe Bove, Stellar, 904-923-4207


Sanitary design as prevention

The principles of facility and equipment design finally have caught up with the fundamental HACCP directive to prevent contamination, rather than react to breeches. The design shift is reflected in the principles of providing zones of control, controlling temperature and moisture and designing to facilitate cleaning, according to Paul Hudale, director-sales for Nutec Group, a York, PA engineering firm.

“Most safety design guidelines revolve around avoiding entry, harborage or buildup in the facility of anything that doesn’t belong,” notes Hudale. While a HACCP plan is specific to the facility, the assessment process it requires has contributed to an emerging consensus on fundamental approaches to sanitary design, such as distinct hygienic zones. Using those fundamentals as a starting point, Hudale extrapolates plant design guidelines, including:

  • Controlled traffic flow of personnel and materials
  • Interior spatial design to promote sanitation
  • Materials of construction and components that promote sanitation
  • Utility systems that prevent contamination
  • Control of water flow, elimination of accumulation
  • Positive pressure, good airflow and filtration in HVAC systems
  • Building envelopes that facilitate cleaning and eliminate harborage for insects and rodents
  • Integration of CIP, steam systems, wash areas and other sanitation systems in new-plant design.