Food processors have a regulatory and ethical mandate to produce safe food. The regulations established by the U.S. Food and Drug Administration and the U.S. Department of Agriculture mandating the establishment of food safety management systems utilizing Hazard Analysis and Critical Control Point (HACCP), sanitation prerequisites, and Good Manufacturing Practices (GMPs) were enacted to ensure a safe food supply and protect the public health. There are many things that food, ingredient, and beverage producers, as well as those handling, storing, and distributing food, can do to meet these mandates. One of these elements is to utilize food processing and handling equipment that has been designed to protect food from potential contamination; or, in other words, has been manufactured utilizing basic sanitary design principles. But what does sanitary design mean?

In the Preventive Controls for Human Food Regulation (21 CFR Part 117.40), the regulation addresses sanitary design as follows:

  • (a)(1) All plant equipment and utensils used in manufacturing, processing, packing, or holding food must be so designed and of such material and workmanship as to be adequately cleanable and must be adequately maintained to protect against allergen cross-contact and contamination.
  • (2) Equipment and utensils must be designed, constructed, and used appropriately to avoid the adulteration of food with lubricants, fuel, metal fragments, contaminated water, or any other contaminants.
  • (3) Equipment must be installed so as to facilitate the cleaning and maintenance of the equipment and of adjacent spaces.
  • (4) Food-contact surfaces must be corrosion-resistant when in contact with food.
  • (5) Food-contact surfaces must be made of nontoxic materials and designed to withstand the environment of their intended use and the action of food, and, if applicable, cleaning compounds, sanitizing agents, and cleaning procedures.
  • (6) Food-contact surfaces must be maintained to protect food from allergen cross-contact and from being contaminated by any source, including unlawful indirect food additives.

These are rather general requirements, so let us look at other guidance that is available to the industry. The focus of this article will be sanitary design of equipment. Issues pertaining to buildings and grounds and other aspects of plant design and maintenance may be addressed in future articles.

Food Safety by Design

Perhaps the best guidelines are the 10 Principles of Sanitary Design established two decades ago by the American Meat Institute (AMI), which today is known as the North American Meat Institute (Meat Institute). Okay, we know you are thinking something like, “We process fruits and vegetables. What should we do with our products?” Bear with us. The AMI’s principles really apply across the board. AMI assembled a blue-ribbon panel from industry to develop this document that was originally issued in 2002. Participating companies included ConAgra Foods, Bar S, Hatfield, Sara Lee, Hormel, Kraft Foods, Smithfield Foods, and Maple Leaf Foods. This taskforce was led by operations, food safety, and sanitation expert Joe Stout from Kraft, who now heads up consulting and training firm Commercial Food Sanitation.

AMI’s sanitary equipment design guidelines, along with a checklist tool aimed to help food processors and equipment manufacturers assess equipment, have been updated over the years.

AMI’s 10 Principles of Sanitary Design were originally released in 2004 and include the following (AMI 2014):

  1. Cleanable to a microbiological level
  2. Made of compatible materials
  3. Accessible for inspection, maintenance, cleaning, and sanitation
  4. No product or liquid collection
  5. Hollow areas should be hermetically sealed
  6. No niches
  7. Sanitary operational performance
  8. Hygienic design of maintenance enclosures
  9. Hygienic compatibility with other plant systems
  10. Validated cleaning and sanitizing protocols

AMI’s sanitary equipment design guidelines, along with a checklist tool aimed to help food processors and equipment manufacturers assess equipment, have been updated over the years. According to the nonprofit Foundation for Meat and Poultry Research and Education (FMPRE), to “leverage the prominence of the Sanitary Equipment Design Principles, the 2021 Food Safety Equipment Design Task Force (FSEDTF) was charged with expanding on existing principles and checklist to encompass all aspects of food safety, with a particular focus on foreign material.” In July 2021, FMPRE released the latest update, now called the Food Safety Equipment Design Principles, which includes references for each principle and details how a processor can audit their equipment based on sanitary design principles (FMPRE 2021).

The 2021 document has changed the order of the original principles of sanitary equipment design as compared to the first release from 2002. “Cleanable to a microbiological level” is now Principle 9 instead of Principle 1. This makes perfect sense since the next principle is validation of cleaning. The change is similar to how the basic HACCP principles were modified to make recordkeeping the seventh and final principle. All the preceding principles require documentation and records.

Changes in Brief

Let’s take a look at each of these principles and how they’ve evolved. The following is a short summary of each of the 10 principles in the order presented in the 2021 Food Safety Equipment Design Principles document. Please note that in the published guidelines and checklist, each principle includes up to 15 individual elements.

Made of compatible materials. Construction materials used for equipment must be completely compatible with the product, environment, cleaning and sanitizing chemicals, and the methods of cleaning and sanitation. Equipment materials of construction must be inert, corrosion resistant, nonporous, and nonabsorbent.

Accessible for inspection, maintenance, cleaning, and sanitation. All parts of the equipment shall be readily accessible for inspection, maintenance, cleaning, and/or sanitation. Accessibility should be easily accomplished by an individual without tools. Disassembly and assembly should be facilitated by the equipment design to optimize sanitary conditions.

No product or liquid collection. Equipment shall be self-draining to assure that food product, water, or product liquid does not accumulate, pool, or condense on the equipment or product zone areas.

Hollow areas should be hermetically sealed. Hollow areas of equipment (e.g., frames, rollers) must be eliminated where possible or permanently sealed (caulking is not acceptable). Bolts, studs, mounting plates, brackets, junction boxes, name plates, end caps, sleeves and other such items must be continuously welded to the surface of the equipment and not attached via drilled and tapped holes.

No niches. All parts of the equipment shall be free of niches, such as pits, cracks, corrosion, recesses, open seams, gaps, lap seams, protruding ledges, inside threads, bolt rivets, and dead ends. All welds must be continuous and fully penetrating.

Sanitary operational performance. During normal operations, the equipment must perform so it does not contribute to unsanitary conditions or the harborage and growth of bacteria.

Hygienic design of maintenance enclosures. Maintenance enclosures (e.g., electrical control panels, chain guards, belt guards, gear enclosures, junction boxes, pneumatic/hydraulic enclosures), and human machine interfaces (e.g., pushbuttons, valve handles, switches, touchscreens) must be designed, constructed, and be maintainable to ensure food product, water, or product liquid does not penetrate or accumulate in or on the enclosure and interface. The physical design of the enclosures should be sloped or pitched to avoid use as a storage area.

Hygienic compatibility with other plant systems. Design of equipment must ensure hygienic compatibility with other equipment and systems (e.g., electrical, hydraulics, steam, air, and water).

Cleanable to a microbiological level. Food equipment must be constructed and be maintainable to ensure that the equipment can be effectively and efficiently cleaned and sanitized over the life of the equipment. The removal of all food materials is critical. This means preventing bacterial ingress, survival, growth, and reproduction. This includes product and non-product contact surfaces of the equipment.

Sanitary design principles are utilized by many operators when looking at modifying existing equipment or purchasing something new.

Validated cleaning and sanitizing protocols. The procedures prescribed for cleaning and sanitation must be clearly written, designed, and proven to be effective and efficient. Chemicals recommended for cleaning and sanitation must be compatible with the equipment, as well as compatible with the manufacturing environment.

A Principled Approach

These are principles, not standards, so there are no limits as to how they can be met. This encourages continual improvement, which is a basic element in food safety management systems. Many food processors have established programs that may be defined as change management. The gist of this program is that a team will evaluate any changes a company makes to operations. Sanitary design principles are utilized by many operators when looking at modifying existing equipment or purchasing something new. It is basically a program that incorporates risk assessment into the equation.

tomato sorting equipment

© vusta/iStock/Getty Images Plus

tomato sorting equipment

© vusta/iStock/Getty Images Plus

According to AMI taskforce member Stout, the sanitary design principles are used by his company for in-house training and hygienic design certification programs across food categories. He also notes that these principles have been translated into many different languages and are now in use around the world. The bottom line is that these principles that were developed by a taskforce assembled by the meat processing industry have gone global. They are applicable to all other processing operations and products, have served to enhance equipment design, construction, installation, and maintenance around the world, and helped to improve food safety and quality worldwide.ft

About the Author

Richard F. Stier is a consulting food scientist with international experience in food safety (HACCP), food plant sanitation, quality systems, process optimization, GMP compliance, and food microbiology ([email protected]).