The pending implementation of FSMA has put the food processing industry on high-alert around issues of food safety. Where does sanitary design fit into this safe new world?

Food processing equipment manufacturers have long worked toward optimizing design to meet the greatest standards of hygiene and efficiency. With ill-defined standards, that hasn't always been easy.

From a 2014 article in Food Engineering magazine:

“Food and beverage industry machine builders know they can't design and build equipment like they would for a machine shop, but they face a smorgasbord of rules and standards—sometimes not so well defined—that can make it difficult to meet the specifications of auditing bodies and government regulators. And if they can't design and build safe, easy-to-clean equipment for food processors, they may as well be building equipment for a machine shop.”

Sanitary design can encompass every aspect of equipment and factory design from conveyors to drainage systems. Food processors and OEMs often look to the pharmaceutical industry for the highest standards of sanitary design. For example, Gillian's Foods uses a vacuum transfer system designed for pharmaceutical applications to move their bread crumbs to packaging.

Perhaps less glamorous than big-ticket items, but no doubt as essential for ensuring sanitary design, is the finish on equipment. For perspective on stainless steel finishes, we spoke to Tom Hoffmann, Director of Sales at MEPACO, a division of Apache Stainless Equipment Corporation. Hoffmann is a big proponent of the ultra-sanitary electropolished finish — another crossover from the pharmaceutical world.

This article takes a look at where the industry stands regarding standards for sanitary design. We then dive into the world of finishes and the viability — in terms of cost and sustainability — of moving into the ultra-sanitary realm.

The Basics of Sanitary Design

Sanitary, or hygienic, design covers four major areas:

  • Materials
  • Surface finish and modification
  • Construction and fabrication
  • Installation, operation, and maintenance

The materials that comprise a food equipment's contact surfaces must be “smooth, impervious, nontoxic, nonabsorbent, and corrosion resistant under conditions of intended use.” High-grade stainless steel is the primary material recommended in the fabrication of food equipment. A passivation process can create additional protection against corrosion.

To be optimally hygienic, surface finishes must be as smooth as possible. Finish smoothness is measured in terms of RA, or roughness average, which is the measure of the peaks and valleys of a metal's surface. The fewer the peaks and valleys, the fewer opportunities for bacteria and other unhygienic materials to collect. That means that a lower RA indicates a higher grade of sanitary finish.

The acceptable RA varies depending on the type of product being handled. For example, a higher-RA finish may be acceptable for processing higher-fat products like butter and meats.

Food equipment must be constructed and fabricated to be free of cracks, crevices, or sharp angles. It must also be pitched to a drainable port and be self-draining. There should also not be any “dead spaces” where fluid can stagnate or collect. Additionally, welds, welding materials, bolts, and threads must be acceptably hygienic.

Finally, there's the area of installation, operation, and maintenance. The majority of food equipment should be cleaned and sanitized using clean-in-place (CIP) systems. Because some manual cleaning is often still involved, equipment must have 360-degree accessibility, including underneath the equipment. All mountings, levelers, and other supports must be properly sealed, with no hollow areas, penetrated framework, or exposed threads that don't meet cleanability standards. Equipment should also be operated in a way that disallows cross-contamination between products.

Navigating Standards

Equipment manufacturers, food processors, and regulatory bodies are actors in a complex, at times ambiguous, scenario ering magazine: when it comes to sanitary design.

According to Joe Stout, Baking & Snack contributing editor, though equipment design is “not regulated at the equipment manufacturer (OEM) level by the FDA, [it] is clearly the responsibility of the food processor being regulated.” That is, FSMA doesn't mandate sanitary design, per se. But because FSMA requires processors to know “the profile and risks of the products they make,” it has become increasingly important for processors to monitor and maintain the food safety parameters of their equipment.

So it's in the best interest of OEMs to create equipment according to the principles of sanitary design, and for food processors to purchase the most sanitary equipment. But who defines those principles and standards?

Many in the industry, particularly in dairy, look to the 3-A SSI Sanitary Standards. According to an article at, these 2014 standards address “cleanability, including materials and surface finishes, radii on wetted surfaces, drainability, cleaning methods, and chemistry plus the ability to expose surfaces to cleaning solutions.”

The meat industry also has its own guidelines for sanitary design. The American Meat Industry (AMI) Foundation published their most recent Sanitary Equipment Design Principles in 2014. Designed specifically to reduce the risk of contamination of food products byListeria, the principles state that all equipment must meet these 10 requirements:

  • Be cleanable to a microbiological level.
  • Be made of compatible materials.
  • Be accessible for inspection, maintenance, cleaning and sanitation.
  • Be free of product or liquid collection.
  • Have hollow areas hermetically sealed.
  • Have no niches.
  • Display sanitary operational performance.
  • Have hygienically designed maintenance enclosures.
  • Have hygienic compatibility with other plant systems.
  • Have validated cleaning and sanitizing protocols.

But what about industries such as baking and other low-moisture foods, which don't have their own regulatory bodies establishing food-safety guidelines?

In a 2014 article from Food Engineering magazine, Steve Blackowiak, food safety manager at Bühler Aeroglide, pointed out that “there is no single source regulation or guideline accepted by low-moisture food producers for hygienic equipment design.” One option that the baking industry has increasingly adopted is to look to USDA sanitation standards for meat and poultry. Equipment manufacturer KOFAB, for example, designs all their food processing equipment to USDA standards, whether it's intended for meat or bakery environments.

To the “Finish” Line

Cleanability is at the heart of sanitary design. And one of the keys to cleanability is a sanitary finish.”Sanitary finish” refers to a smooth, scratch-free, non-corrosive finish. Several criteria are used to designate and describe finishes:

  • Surface texture describes the overall surface of the material, including any irregularities, as well as roughness and grain.
  • Grit is the size of the abrasive used in the polishing process. Higher numbers are associated with polishing, while lower numbers refer to grinding.
  • Roughness average (RA) is the average of peaks and valleys of a metal's surface, measured in microinches or micrometers.

Both mechanical and chemical processes are used to achieve a polished finish. Mechanical polishing removes material using an abrasive process. Chemical surface treatments remove the outer layer of corrosion in the metal. The food processing industry uses a variety of chemical and mechanical finishes, depending on the product being processed.

The following table, courtesy of Apache Stainless Equipment, provides an overview of common finishes and their applications:

DescriptionApplicationsSanitation EnvironmentRA
MillThe baseline for comparison, this is unfinished steel in basic supply conditionStructuralNone–not used in food contact areas>100 microinches depending on material
2BCommon corrosion resistant, heat resistant, smooth, (not brushed) steelMaterial handling, processing, direct food contactSuitable for caustic sanitary wash down procedures36 (7 gauge) to 15 (16 gauge) in microinches
No. 4Characterized by short, polished brushed linesUsed in clean rooms and in food processing equipmentSuitable for caustic sanitary wash down procedures29 to 40 microinches
No. 4AAlso characterized by short, polished brushed lines, the 4A finish uses a finer grit polishUsed in clean rooms, processing equipment, used in pharmaceutical industries and complies to 3A Dairy standardsSuitable for caustic sanitary wash down procedures18 – 31 microinches (3A standards require 32 or less)
Bead BlastA uniform, non-directional, low-reflective surface; bead blasting can be mechanical or chemical (dry ice)Used when a uniform finish is desired in structural, material handling or food handling applicationsBead blasting on common 304 and 316 stainless material is suitable for caustic wash down procedures>45 depending on blasting process



PassivationA chemical (typically nitric or citrus acid) treatment that produces a formation of a protective passive film on stainless steelMost stainless steel material is passivated, polished or treated in some way to prevent corrosion; passivation may also be a federal specificationPassivated stainless material can withstand caustic wash down proceduresRA values have no significant improvement after passivation*
Pickle PassivationAlso referred to as descaling, pickle passivation removes the scale and leaves a clean matte finish free from contaminationUsed in pharmaceutical industries as a federal specification and in food processing industries to reduce food safety riskSuitable for caustic, aggressive sanitary wash down environmentsDepending on material, pickle passivation can result in up to 25% increased smoothness measured in RA*


Surface metal is dissolved, removing all embedded contaminants, creating a smooth, mirror finishUsed in pharmaceutical industries as a federal specification and in food processing industries to prevent bacterial attachment and reduce food safety riskHighest grade of passive surface available, can be subjected to long term, caustic wash downDepending on material, electropolishing can result in up to 50% increased smoothness measured in RA*

*Apache In-house finishing before/after tests; results vary depending on stainless material.

According to Tom Hoffmann, customers used to rely on a standard bead blast finish. This process uses “bead” material such as glass, ceramic beads, or dry ice to produce “a non-directional, textured surface with a soft satin appearance and low-reflectivity.”

Nowadays, Hoffmann is most excited about the electropolish finish, which is a crossover from the pharmaceutical industry. While other finishes meet 3-A standards around surface qualities and lack of cracks and crevices, these minimum requirements do not necessarily result in optimum cleanability.

According to Hoffmann, electropolish is the gold-standard in sanitary finishes because it hits three major criteria:

  1. It meets the standards of sanitary design.
  2. It cleans up easier.
  3. It cleans out easier — making it so that less residual yield is lost from batch to batch.

An electropolished finish not only meets but exceeds industry standards. With RAs in the single digits, wiping your hand across an ultra-sanitary electropolished surface is, Hoffmann says, like wiping your hand across a mirror.


l-r: 304 Stainless Steel 2B Finish15 – 17 RA (12 gauge), 304 Stainless Steel Electropolished Finish 5 – 6 RA, 304 Stainless Steel 2B Finish 20 – 30 RA (10 gauge), 304 Stainless Steel Bead Blast Finish 35 – 45 RA

Does Sanitary Design Make Financial Sense?

While exceeding sanitary design standards may sound like a good idea in theory, putting ideas into practice requires capital. Does sanitary design provide a satisfying return on investment?

Or is that not the right question to be asking? Writing in Food Safety Magazine, Randy Porter points out that many companies expect an ROI within two to three years. But Porter argues that looking at sanitary design from only a capital perspective risks missing the point.

Inasmuch as sanitary design relates to food safety, it's true that putting rigorous oversight procedures in place might seem to require less outlay than investing the capital in new equipment. But, Porter reminds his readers, “Sanitary design is the application of design techniques that allow thetimely andeffective cleaning of the entire manufacturing asset” [emphasis added]. If a piece of new, sanitarily designed equipment can be cleaned in less time than its older counterpart, then operational costs over time will surely see a positive impact.

For example, one of the biggest advantages of an electropolished surface is the ease of cleanup. On rougher surfaces, like bead blast surfaces, product can build up over the course of a day's run. Tom Hoffman says it's not uncommon for sanitation workers to come in at the end of the day with Scotch-Brite and hoses to scrub down the equipment.

With electropolishing, less residual product sticks to the contact surfaces of the equipment, which means less manpower, water, and time are required for cleaning and sanitization. In this way, this type of ultra-sanitary equipment provides significantly more value than first meets the eye.

Sanitary design also affects product success. According to Porter, product produced on equipment fabricated according to the principles of sanitary design is less likely to be rejected, reworked, or placed on hold. And using sanitary design principles may also result in lower potential for recall of contaminated products. With the average cost of a recall up to $10 million, that's a risk no company wants to take.

Considering the savings in operational costs over the long term, as well as the reduction in costly food-safety failures, there's no doubt that sanitary design makes good financial sense.

Going Greener

Adopting ultra-sanitary design may make companies greener, too.

Hoffmann said that electropolishing reduces the amount of product that clings to product contact surfaces. Thus, companies can invest not only less manpower but also less water and fewer chemicals to clean equipment.

Even one of the standbys of sanitary design, clean-in-place (CIP) technology, is making strides toward greater water conservation and sustainability. Here are a few success stories:

  • Wisconsin-based Sani-Matic worked with a brewery to recover water from one cleaning cycle to the next, reducing the company's water consumption by 50%.
  • Canadian company Ontrack Project Solutions worked with an Ontario dairy to streamline water usage by using the company's eView monitoring system and doing some reprogramming.
  • Tetra Pak Processing Systems' IntelliCIP detects the thickness of detritus during the cleaning process, allowing a food processor to shut down the CIP wash before the recommended minimum time is up if the equipment is clean.

With more focus on improving energy efficiency, expect to see sanitary design and eco-friendliness continue to go hand in hand.

Beyond Just Sanitary

MEPACO's Hoffmann puts it plainly: “Building a sanitary piece of equipment is table stakes.” Surely, food processing companies can extend Hoffmann's metaphor to purchasing and maintaining sanitary equipment.

Hoffmann sees momentum in the industry to reach for equipment that is “ultra-safe and ultra-sanitary.” If this equipment proves beneficial in the realms of cost and sustainability as well, perhaps food processing companies will agree with Hoffmann and MEPACO: standards are made to be exceeded.