Hygienic Design for Processing Equipment

In 1944, the U.S. Public Health Service offered full cooperation with the 3-A program, which marked the beginning of a program to provide uniform equipment standards for the protection of public health. This integral participation of the regulatory sector of the industry has become important as the food industry complies with the requirements of the Food Safety Modernization Act (FSMA). Under FSMA, the industry must be able to demonstrate and document that they have implemented the necessary steps to assure the wholesomeness of the products they produce and the effectiveness of the cleaning and sanitation programs they employ. 3-A Sanitary Standards’ involvement directly benefits the equipment fabricator and the processor through the routine acceptance of the equipment during regulatory inspections.

Today there are 68 3-A Sanitary Standards and nine 3-A Accepted Practices. These documents cover a wide range of the basic equipment used in most food processing applications such as pumps, valves, sensors, heat exchangers, and vessels. There are also standards for specialized equipment for packaging, drying, conveying products, etc. A particular piece of equipment can demonstrate that it has been evaluated by a third-party evaluation and conforms to the hygienic standard requirements with the display of the 3-A symbol.

Over decades of collaboration and recognition among the key stakeholders, the 3-A brand has attained wide recognition in the marketplace for food processing equipment and special stature built on a strong foundation of the following elements: trust, independence, and expertise.

From the Design Up

Food processors continuously look for the holy grail of increased production, reduced cleaning time, and reduction of costs. These are the areas in which hygienic standards excel. It is desirable to be able to clean the equipment fully assembled or with a minimum of disassembly, and subsequent reassembly; clean-in-place or CIP as it is known in the industry. This is not as simple as just attaching a spray device and a solution return line to the piece of equipment. Even as basic a piece of equipment as a storage vessel with an agitator requires specific engineering to effectively and safely clean fully assembled. Saying that CIP is possible in a sales brochure does not necessarily make it so.

Hygienic design starts with the very first lines drawn on a blueprint. The first task of the designer is to determine what is to be considered a product contact surface in order to assure that the design will fully protect the product from contamination. In hygienic design, a product contact surface is defined as, “All surfaces which are exposed to the product and from which splashed product, liquids, or soil may drain, drop, diffuse, or be drawn into the product or onto surfaces that come into contact with product surfaces of packaging materials.” This definition directs the designer to consider all of those areas of the equipment, which may be over exposed product or open containers in filling machines.

The possibility for successful CIP cleaning has to begin with the basic concept designs as the equipment develops. Every aspect of the design has to be evaluated through the filter of CIP. The concept of the elimination of creaks and crevices must be paramount. Any surface that is exposed to product must also be exposed to the cleaning and sanitizing solutions. Not only exposed, but with sufficient tolerances so that the cleaning solutions can freely circulate to dislodge and flush away product residues. This leads the designer to consider the proper placement of gaskets and seals, the elimination of dead ends where product residues cannot be removed during either processing or cleaning, selection of a cleanable surface texture, selection of materials that will withstand the chemicals and temperatures encountered during processing, cleaning and sanitization, and the inclusion of a proper slope and drainage of the equipment. This list of design considerations increases as the sophistication of the equipment increases. Inclusion of spray cleaning devices opens up design consideration for flow patterns, component placement to eliminate the possibility of shadow areas that will not be properly treated. The attachment of appurtenances, such as valves and sensors and personal access ports, raise more issues that the designer must consider to assure cleanability, as well as the inspectability of the interior product contact surfaces. No matter how efficient a cleaning system is designed, the surfaces have to be inspected periodically. Inspectability and access to the product contact surfaces is a must for assuring continuing cleaning success.