Tech Update: Sanitary Design

March 1, 2009
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Aggressive cleaning programs and advanced technologies are improving food plant hygiene, but sanitary design principles also should be considered.

This aseptic gearmotor from SEW-Eurodrive strikes a balance between hygienic design and the functional needs of a power source that delivers extended service. Source: SEW-Eurodrive Inc.



Who’s the best person to turn a primal cut into a New York strip: a butcher or a surgeon?

If money were no object, the properly gowned and scrubbed medical specialist could deliver an exquisite cut. Money is always an object, though, and a skilled butcher would handle the task nicely.

Tradeoffs between what’s possible and what’s practical confront food professionals as they design sanitary solutions for their facilities. Fundamentals are constant; execution is subject to review. “There are a hundred decisions to be made on every design concept, and there is no rule book on how far you should go,” observes David C. Dixon, executive vice president of Smyrna, GA-based Facility Group’s food & beverage unit. “It’s not a science-based decision; a lot of it has to do with the culture of the company and the risk tradeoffs.”

Tradeoffs between what is possible and what is affordable shape sanitary design, agrees Joe Bove, vice president of design engineering for Stellar Inc., Jacksonville, FL. Priorities must be set, with fiscal compromises made in areas where risks are minimal. To illustrate, he cites a current project involving separate zones for preparation, cooking, chilling, packaging and palletizing. The greatest risk resides in the chill zone, where a separate refrigerated-air makeup unit will serve the room. Better to pay a premium for maximum product protection in this “heartbeat zone” and look for cost savings elsewhere.

Five years ago, Bove and Dixon were members of an American Meat Institute task force that crafted 11 principles of sanitary design for meat and poultry plants. The facility guidelines, which complement similar checklists for equipment design, drew strong agreement from participants on the basics, but extensive debate on how far a plant should take any particular point, recalls Dixon.

In their assessment of Peanut Corporation of America’s shuttered Blakely, GA, facility, FDA inspectors noted several deficiencies addressed in those design principles. Lack of segregation between raw and finished goods was a major criticism of the plant linked to a deadly strain of salmonella. The need for segregation is outlined in the engineers’ first two principles (see related story on page 58). Likewise, FDA inspectors criticized bay-door gaps large enough to allow rodents and pests to enter, a deficiency addressed in principles 7 and 9.

While many mortal sins were committed at Blakely, venial infractions aggravated the situation. They could have been avoided with a better understanding of environmental risks in food safety. Microbes need water, and eliminating surface condensation and excess humidity would have bolstered the plant’s sanitary performance. Likewise, food-contact surfaces that could adequately be cleaned and sanitized would have satisfied a principle in both AMI’s equipment and facility guidelines: “cleanable to a microbiological level.”

Sanitary lapses between the time a product is processed and when it is placed in its final package are critical concerns for many food companies. Source: SEW-Eurodrive

Priority setting

Cleanable to a microbiological level is an admirable goal, but achieving it in noncontact zones is neither practical nor necessary. In the case of flooring, an epoxy or polyurethane coating might be the best defense against bacteria in check, yet operating conditions can compromise those materials.

“Epoxy is good in rooms where people in rubber boots are the only traffic,” Dixon notes, “But microbes turn up quickly when there’s a little forklift damage.” As more attention is paid to sanitary conditions, “people are going back to brick,” he says. The material comes at a premium cost, but the ability to quickly replace a damaged brick makes the cost of ownership attractive.

West Liberty Foods used epoxy with an antimicrobial additive in critical areas in its ready-to-eat deli meats plant in Tremonton, UT (see “Fabulous Food Plant,” Food Engineering, December 2008). Former plant engineer Rick Roedl lauded the installation work and the flooring’s cleanability, yet in the first year’s operation, repair work already was required in some slicing rooms, as thermal shock during high-pressure washdowns created tiny channels for runoff water. Trench-drain failures also were evident in heavy-traffic areas.

Structural glazed facing tile is a popular choice in dairies, while brick is gaining fans in meat plants, says Bove. Tight joints and well-maintained grout require an expert installer, he says, cautioning, “People tend to forget a floor after it’s poured. Floors, like wall surfaces, need to be inspected, replaced and repaired when necessary.”

Raised platforms and ramps pose special challenges. Sanitation is important, yet worker safety also is a priority. Diamond checker plate presents issues on both counts, and various alternatives exist, such as epoxy with oxide resin over concrete. Campbell Soup pioneered the use of molten metal plasma on a stainless steel substrate 20 years ago, though sanitizing such a surface to a microbiological level is a challenge.

Safety and productivity improvements are the drivers for those surfaces, Slipnot Metal Flooring’s Jeff Baxter notes. The factory process binds metal plasma to the substrate with more than 4,000 psi pressure, and the coating is hardened to 400 Rockwell. “It’s like a milling process,” he explains, and no antimicrobial can be added. If animal fat or other material spills, manufacturers are advised to use a bristled brush to remove it from the 0.02 inch deep tread. Swab tests suggest the coating is as cleanable as diamond plate, according to Baxter.

Human contact with the product was minimized at the West Liberty plant. One exception is the transfer between slicing and packaging machines, where operators grab 2 lb stacks of sliced meat and place them into thermoform nests. Robotics are the alternative, and that solution was recently deployed at a European RTE plant, according to Scott Scriven, CEO of Kansas City-based Weber North America, the supplier of West Liberty slicing machines. High labor costs make ROI from automation an easier decision in Europe, he adds. The equipment, similar to a welding robot, “really doesn’t take up any more room than the three ladies” who manually pick and place sliced meat, he says.

At West Liberty, Scriven’s firm partnered with Multivac Inc., another Kansas City firm, on the slicing and packaging setup. The infeed from the Weber slicer extends up to 10 ft. into the packaging zone, with very little clearance underneath. To facilitate sanitation, pneumatic lifts were installed on the infeed to raise it 45 degrees during washdown.

The thermoform machine exemplifies dairy’s clean-in-place approach applied to an RTE meat environment. The availability of more rugged pneumatic and electronic components made packaging machine CIP possible, according to Jan Erik Kulmann, Multivac’s president and CEO.  A system of jets and pipes delivers water and chemicals to zones in the unit. Sloped surfaces and a drainage system that eliminates pooling were critical design elements. An automatic greasing system lubricates the machine’s chain after the CIP cycle, extending the chain’s life four times longer than in a conventional thermoform, says Kulmann.

“The AMI principles guided us,” he adds. “Instead of enclosing everything, we made a very open structure.” The machine, which also is applied in cheese packaging, is 3A certified.

The impetus for a sanitary redesign was set in place a few years ago when Multivac sent its engineers into the field to better understand the food environment. “They got pictures to horrify their families and friends of green meat caught in nooks inside the machines,” Kulmann grimaces.

An open design and elimination of crevices, dead-ends and shadow zones also drove a redesign at Sealed Air’s Cryovac Food Packaging division in the wake of the AMI sanitary guidelines. A stainless steel frame, corrosion-resistant aluminum-alloy chambers and a foot of floor clearance were among the design improvements made to a rotary chamber vacuum machine, explains William Bartell, North American equipment marketing director at the Duncan, SC, machine fabricator. “Making it cleanable to a microbiological level was the top priority.”

“It was the most complete redesign since the 1970s and resulted in a striking difference over the old system,” adds Bartell. More than 2,000 of the machines have been commissioned in the last three years.

Accessibility for cleaning and filter maintenance are the advantages of this rooftop unit for refrigerated makeup air. UV lights to sterilize the cooling coils are built into this unit. Source: Facility Group.

Budgets are finite, and more stringent sanitation requirements don’t always acknowledge the reality that pouring capital into one area can create problems in others. Poultry operators’ switch to stainless steel motors is a case in point. Stainless is the material choice for aggressive cleaning, but those motors pose condensation issues, and they dissipate heat poorly. A middle ground between stainless and cast iron is being staked out by SEW-Eurodrive, which rolled out its aseptic gearmotor in the fall. The Lyman, SC, power-transmission firm is trying to strike a balance between possible and affordable while also delivering an upgrade in sanitary operations. Processors don’t need the same sanitation in rendering and chilling.

The power system’s smooth surfaces and lack of recesses borrows from motor housings used by the company’s servo group, says Chris Wood, food industry account manager. An oversized body was needed because cooling fins were eliminated. Stainless steel shafts and other components, and seals and rings of chemical- and heat-resistant synthetics bolster the hygienic value.

“Not only does a motor have to be hygienically acceptable, it also has to survive the environment and give long life,” Wood says. The tradeoffs necessary are dictated by the application. Each manufacturer has to make those calls; the supplier’s role is to provide options to fit the specifics. Various coatings are available for the gearmotors, from a simple epoxy top coating and primer to a multi-layer coating that takes two weeks to dry. An antimicrobial compound in the top coating is being considered, he adds.

Conveyors are the hygienic Achilles heel in many plants. The cross-contamination potential is great, yet until recent years sanitary conveyors were an afterthought. A decade ago, modular plastic belts began replacing tension belts, giving manufacturers a material less supportive of microbial growth. Beginning in 2004, extruded urethane ThermoDrive belts debuted from Mol Industries, Grand Rapids, MI. The ThermoDrive hygienic belt weighed less than half as much as modular plastic, was easier to clean and more closely reflected the AMI principles of sanitary design. In 2007,  Dorner Manufacturing Corp., Hartland, WI, introduced a line of sanitary conveyors for food processors, and Mol became a preferred supplier.

Mol’s hingeless belts were positioned squarely against Intralox, the New Orleans-based pioneer in modular plastic belts. In November, Intralox became the exclusive North American distributor and licensee of ThermoDrive. Concurrently, Intralox has continued to upgrade its plastic belting, adding angled sprockets and CIP systems to reduce cleaning time and water use and extend run time, particularly in meat processing.

Sanitary options are addressed with Dorner’s newest washdown-friendly food conveyor. It can be viewed as the good line in a good, better, best assortment for food manufacturers, allows John Kuhnz, food marketing manager. Processors of baked goods, snack foods and fresh-cut produce don’t have to guard against the health threats in ready-to-eat meats or dairy products. Dorner’s AquaGard conveyors trade sanitary overkill for high operating speed (up to 260 ft. a minute). Belting options also are extended to include open mesh, closed top and cleated belts.

Professionals from meat companies and engineering service firms did the industry a service in outlining design principles for sanitary food and beverage production. They are not a how-to guide but a useful summary of key points to consider. Technologies that make ever-higher standards possible will continue to be developed for industry segments or migrate from the medical and pharmaceutical fields. Each manufacturer must evaluate those tools in the context of the critical areas of their processes and where the opportunities for flexibility reside.

For more information:
William H. Bartell Jr., Cryovac Food Packaging, 864-433-7066, bill.bartell@sealedair.com
John Kuhnz, Dorner Manufacturing Corp., 262-369-1332, john.kuhnz@dorner.com
David Dixon, Facility Group, 770-437-7155, david.dixon@facilitygroup.com
Jim Honeycutt, Intralox, 616-901-0885, jim.honeycutt@intralox.com
Joe Bove, Stellar Inc., 904-899-9370, jbove@stellar.net
Scott Scriven, Weber Inc., 816-891-0072
Jan Erik Kulmann, Multivac Inc., 816-891-0555
Chris Wood, SEW-Eurodrive Inc., 804-740-2269
Jeff Baker, Slipnot Metal Safety Flooring, 313-923-0400, jeffb@slipnot.com

Food Facility Design Principles

When architectural engineers and food plant design specialists drafted a broad outline for facility sanitary design, they went their meat and poultry equipment counterparts one better by establishing 11 guiding principles. The American Meat Institute convened the group, but the concepts are useful reference points for all types of food and beverage production.

    1.    Establish distinct hygienic zones with physical separation to minimize hazardous transfers.

    2.    Control material and personnel flow to minimize food-safety risks.

    3.    Ensure water is evacuated from the process area and does not accumulate.

    4.    Control room temperature and humidity to deprive microbiological life of water.

    5.    Control airflow and quality; minimize surface condensation.

    6.    Grade and control access to the site to facilitate sanitation.

    7.    Design a building envelope that keeps out insects and rodents.

    8.    Provide adequate interior space for cleaning, sanitizing and maintaining process systems.

    9.    Use durable materials and joint sealers to prevent harborage points; isolate utilities with interstitial spaces and stand offs.

    10.    Design utility systems to prevent contamination; create surfaces cleanable to a microbiological level.

    11.    Facilitate sanitation systems that minimize chemical, physical and microbiological hazards.

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