The information below addresses some key elements for the hygienic design of food processing equipment. It is important for the hygienic design team to determine when a piece of equipment, or component, is rendered inoperable due to age, particularly as coatings on equipment can chip, creating rough surfaces, and constant equipment repairs can result in unreachable gaps.
New designs and technologies are always emerging to help with food safety solutions, but hygienic design of equipment should always be front and center to a facility’s food safety plan as it can significantly reduce the prevalence of Listeria monocytogenes (Lm).
What is dead space and why should I be concerned?
What the operator cannot see or access is often times the most common culprit associated with contamination. Dead spaces where food, cleaning agents or microorganisms are trapped or retained and not completely removed by cleaning can develop into serious issues. When considering a new piece of equipment, a quick visual inspection of food contact and non-food contact areas for dead spaces is an essential step. In addition, installation of equipment should be performed in such a way as to eliminate dead spaces and prevent the creation of dead spaces.
What other elements are essential for hygienic design of food processing equipment?
Equipment design should include elements that will readily eliminate soil by manual cleaning, such as:
• A smooth and continuous radius in food contact areas and along internal corners
• Easily cleanable surfaces that are free from pits, pinholes, cracks, crevices, inclusions, rough edges and other surface imperfections
• Detectable by visual and tactile inspections
• No exposed threads and grooves in food contact areas
• Metal to metal joints that are continuously welded and flush
• Equipment designed to drain, preferably self-draining (sloped in an appropriate gradient)
What is the most effective method of cleaning?
There are two ways of cleaning equipment, manual cleaning and cleaning in place (CIP). A piece of equipment that is readily accessible should be designed so manual cleaning will remove soil. Occasionally, simple tools will need to be used to remove dirt, dust and debris by manual cleaning. When manual cleaning is not possible, the manufacturer of the equipment should provide clear and concise CIP instructions, including frequency, chemical requirements and cleaning procedures. Validation that the CIP process outlined by the manufacturer is effective should be made available. No single cleaning method is usually more effective than other methods. Therefore, cleaning should always involve a combination of multiple approaches. For instance, manual removal of bacteria combined with a sanitizing step can be more effective. Should I be concerned about gaskets and rubber components?
Gaskets and rubber components are acceptable if designed and used appropriately. Excessive pressure on gaskets and rubber can cause damage to these components and cause them to extrude and potentially come in contact with food. As an example, if an elastomer is used as a seal between two solid surfaces, the level of compression can be managed to control this risk. In addition, gaskets, and O-rings should be non-porous and non-absorbent.
What do I need to know about materials used in food processing equipment?
Materials and surfaces comprising of heavy metals or other hazardous substances should not be part of food processing equipment. In general, materials should be corrosion-resistant both to the food product and to cleaning and sanitizing chemicals. Any non-metallic material should meet 21 CFR parts 174 – 189 for their intended end-use and the equipment manufacturer should provide documentation. Materials that are not easily cleanable, such as wood, should be avoided.
Coatings are an acceptable way to treat food contact surfaces. When inspecting equipment with coated surfaces, visual observations can identify problems such as pitting, flacking, blistering, or other distortions in the integrity of the coating. These types of coating defects result in crevices where soil and bacteria can accumulate.
Are there special consideration for conveyors?
Food product conveyors and conveying systems can make up a large portion of the food processing facility. The belting material and design should be cleanable manually in place. Manufacturers should provide validation of the cleaning process from appropriate certification and auditing bodies, such as the National Sanitation Foundation. In addition, conveyor support systems, such as sprockets, rollers, pulleys, shafts, bearings and other accessories should either be cleanable by the CIP method or sealed. Conveyors should be designed so that subsequent to a CIP step, a visual inspection of the equipment is possible.
How important are the surfaces of structural equipment in a facility?
Focusing on the equipment that is in direct contact with food is critical, but structural surfaces also pose risks of microbial harborage and contamination. Some floors, especially older ones and those subject to forklift traffic, have pitting and broken concrete that can be challenging to clean. Depending on the age of the facility, there are different drain designs and systems that can harbor bacteria. Using a cleaning product that has been registered for food contact and food handling facilities and following through on the instructions (length of time chemical remains on surface, the amount of chemical on the surface) can help control these contamination risks. In addition, equipment not used directly in processing (floor sweeper, forklifts, etc.) should also be cleaned manually in place and their components replaced when appropriate.
