Here’s the second of a four-part report on “10 Principles of Equipment Design for Low-moisture Foods.”

By Joe Stout

During the modification of the Principles of Sanitary Design, one of the most important discussions centered on the lack of understanding and/or use of standards or certification pertaining to sanitary design of equipment. While there are many good sanitary design standards available for food processing equipment, they sometimes are not well understood, and in some cases perhaps unread, due to their length and complexity.

Given this challenge, the team’s first goal was to develop a framework by which all dry processors and equipment manufacturers could understand the intentions and expectations of the many existing standards. To do this, the team began by looking at a variety of approaches used around the world in an attempt to capture the essence, critical points and benefits of each.

In discussions with equipment manufacturers, we learned that many processors ask equipment suppliers for a variety of different designs, and these requests vary widely from processor to processor, for the same piece of equipment. This is considered a disadvantage from a supplier’s point of view.

The supplier’s request is: can we have a design that is accepted by all rather than doing a design for Company A, and then do a different design for Company B – after all they both make and pack the same type of products?

The answer is yes!

By developing an industry-appropriate model with the best design for cleanability that would be used by the industry rather than a specific company, all processors would benefit from the improved design, and suppliers would have a streamlined approach.

In many ways, it would be like raising all boats at the same time the water is being elevated. In the long run this will help processors, equipment suppliers and ultimately the consumers. Equipment supplier companies who improve designs will have an advantage, as the industry gains enhanced awareness of sanitary design.

From the processor’s perspective, looking at the impact of sanitary design over the life cycle of equipment is very important from a cost and operations perspective. Since most plant equipment has a life cycle of 20 years or more and as such a good design will benefit a company, while a poor design will place a burden on production expectations and sanitation resources for years to come.

Each of the 10 Principles of Sanitary Design address an important aspect of sanitary design associated with the successful implementation of what will become an industry model.



Principle 1. Cleanable.

Equipment should be constructed to be cleanable to GMP (good manufacturing practices), product hazard (microbiological, chemical, physical) and quality levels, that is validated and verified by active monitoring programs.

Food equipment must be constructed and be maintainable to ensure that the equipment can be effectively cleaned and sanitized over the lifetime 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.

Processors would like to see a piece of equipment that can be cleaned to a microbiological, chemical and physical level. This principle, based on HACCP, refers to any kind of unwanted contaminant including pathogens, allergens or physical contaminants.



Principle 2. 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.

This principle emphasizes the importance of making sure that a product surface is impervious to the materials to which it is exposed. This is important because the use of incompatible materials may cause subsequent corrosion or pitting on a material such as aluminum if exposed to chemical and or some food products. Once corrosion or pitting occurs harborage points are created where microorganisms, water, soil or food can collect.

Fundamentally, the processor wants to minimize areas where microorganisms or allergens can harbor and potentially contaminate products. By eliminating incompatible materials in the construction of the processing equipment, the processor reduces the likelihood of creating a hospitable environment to harbor a food safety risk.



Principle 3. 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.

If you can’t see it or touch it, then you can’t clean it or sample it. In other words, in a non-clean-in-place environment, you need access to contact surfaces to enable cleaning. There are four elements of cleaning that processors use: mechanical action, temperature, a chemical that will break up fats and proteins, and time. With these four elements, the processor should be able to remove any food soil from equipment, so long as they get the mechanical action and chemicals for the needed time and in the right concentration into areas where soils are present. Designing equipment to increase accessibility for cleaning ensures the success of this four-element protocol.

The more accessible the equipment for cleaning by sanitation employees, the easier it is for them to do the job properly and procedurally. If you need to clean an inaccessible area maintenance must be called to remove a guard or to gain access to an inaccessible area. This takes more time and makes it difficult to get the job done. This principle underscores the benefit of making processes easy for people to do the right things.



Principle 4. No Product or Liquid Collection.

No stagnant product build-up or liquid collection areas. Equipment should be self-draining to assure that residues do not accumulate or pool on the equipment or product zone areas.

There should be no product or liquid collection because the processor does not want to have any areas in the system where water or product can collect and later develop into a foreign material as it dries out, crusts and hardens. Standing water can serve as a harborage or growth point for microorganisms, and when moisture is introduced into an environment, there is an increased chance for microbial growth. It is important to note that for dry cleaning, there is generally little water if any used, however there are some situations where the need may be warranted. If water is needed and used, it is critical to emphasize the ability to assure thorough drying.



Principle 5. Hollow Areas Eliminated or Sealed.

Hollow areas of equipment must be eliminated whenever possible or permanently sealed. Items such as bolts, studs, mounting plates, brackets, junction boxes, nameplates, end caps and sleeves should be continuously welded to the surface and not attached via drilled and tapped holes.

In most food processing plants, there is a great deal of framework supporting equipment. It is important to ensure that there are no penetrations that would allow moisture and/or food materials or organic matter to get inside or under the surface of equipment. If this occurs, microorganisms will grow, leach out and potentially contaminate the environment.

Eliminating hollow areas or sealing them is a principle easily addressed by equipment designers. An example of this is when an equipment manufacturer would attach a nametag on the piece of equipment, using a pop rivet. A pop rivet is a penetration of the equipment surface that is not sealed, allowing water to penetrate the hollow area. Many designers are eliminating the pop riveted nametags today.

Editor’s Note: Next week, in our next installment in this series on sanitary design, Joe Stout will go the final five principles. A food scientist by education, Stout has worked for Kraft Foods for 28 years in the areas of operations, sanitation, and quality. He is a registered sanitarian with the State of Pennsylvania. Stout is the facilitator of the GMA Equipment Design Group for Low-moisture Foods. In addition to having experience in equipment design in dry processes, he was also chairman of the American Meat Institute Equipment Design Task Force, and has been active with 3A and the EHEDG.

Click here to read Part I of the “Sanitary Design as an Enabler of Food Safety” white paper.  

Click here to read Part III of the “Sanitary Design as an Enabler of Food Safety” white paper.  

Click here to read Part IV of the “Sanitary Design as an Enabler of Food Safety” white paper.