Hygienic design impacts all elements of the food manufacturing infrastructure, including equipment, the facility, buildings and grounds. This section outlines key principles of hygienic equipment and facility design with illustrative examples frozen food companies can implement to best address Listeria monocytogenes (Lm) risks.
Hygienic Design Recommendations
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A WELL-ROUNDED HYGIENIC DESIGN TEAM
Members of the food safety/sanitation staff trained in equipment and infrastructure hygienic design are requested for input on hygienic design prior to the initiation of project start-up.
CHARACTERISTICS OF HYGIENIC FOOD CONTACT SURFACES
All food contact surfaces are seamless, with rounded corners and are constructed of materials that can be properly cleaned and sanitized. These materials should be non-toxic, nonabsorbent, corrosion resistant and highly resistant to cleaning and sanitizing chemicals
DESIGN OF FLOORS AND WALLS
Floors are generally cleanable, non-porous and show no cracks. By design, floors are resistant to chemicals used. Floor/wall junctions are completely sealed. Concrete base sealed with epoxy or urethane material which is chemically resistant or dairy brick with continuous grouting. Coved at floor/wall juncture for good drainage. Floors very durable to extreme conditions. For dry areas: use smooth finish to allow for dry cleaning that is resistant to chemicals and cracking.
DESIGN OF STORAGE AREAS
Floors are clean with minimal items stored as determined by immediate production needs and are staged for use. Guidelines are followed for storing items on the floor which belong there. Food containers, packaging and other sensitive items are off of the floor. Tables and cabinets are made of non-corrosive materials and stored 12 inches off of the floor.
DOCUMENTING EQUIPMENT AND FACILITY MODIFICATIONS
Equipment and infrastructure modifications that are conducted to improve hygienic design are documented and undergo a structured verification process to document confirmation of efficacy.
Water pressures are controlled so that atomization is minimized to prevent cross-contamination. High pressure hoses are not utilized during equipment or drain cleaning. Sanitation personnel are trained and monitored to control direction and quantity of rinsing and aligned with sequential cleaning process requirements.
Drains are smooth, cleanable – no rust or pitting.
EVALUATING HYGIENIC DESIGN OF EQUIPMENT
Team utilizes a hygienic design checklist for equipment and a hygienic design checklist for infrastructure in conjunction with other standards. Audit results are reviewed and acted upon by the facility team in an organized and documented manner.
EVALUATING HYGIENIC DESIGN OF THE FACILITY
A review of facility infrastructure and equipment is conducted in conjunction with respective corporate staff or outside entity with expertise to identify existing poor hygienic design points and identify corresponding mitigation actions.
EVALUATING NEW EQUIPMENT
New equipment design is reviewed by trained personnel for hygienic design compliance from concept to start to identify and mitigate areas of concern related to hygienic design.
A floor maintenance programs exists and is followed for floor inspection and maintenance. A process for creating work orders to repair or replace floors is in place and used.
HYGIENIC CEILING DESIGN
Facility ceilings are solid, smooth, cleanable, accessible, and moisture resistant. Lighting is recessed. An ongoing inspection and repair program is present. A facility food safety hazard evaluation is ongoing with remedial actions identified and implemented.
HYGIENIC CONVEYOR BELT DESIGN AND USE
Product conveyors are located a minimum of 18 inches off the floor and from the ceiling (for overhead conveyors). Conveyors are placed in easy to access areas to facilitate cleaning. Conveyor usage is minimized and if placement is strategic with considerations of proper cleaning and inspection.
HYGIENIC DRAIN DESIGNS
Floor drains are circular and not directly under equipment or processes (or covered during production). Easily accessible and cleaned during each sanitation cycle or sanitized daily. Level with floor surface and of sufficient size and distribution to take away water and resist backups. Trench-style drains only when necessary in post lethality/high hygiene areas, continuously welded and stainless steel.
HYGIENIC EQUIPMENT DESIGN
All food contact equipment is designed prior to purchase and installed to be self-draining and not entrap water and soils, provide access for cleaning and inspection and are able to withstand the plant environment.
HYGIENIC FACILITY DESIGN
Facility design defines hygienic zones and dedicated entry points with hurdles to sensitive processing areas. Proper mitigation steps are identified and implemented for all points of entry into processing areas.
HYGIENIC FLOOR DESIGNS
Floors are sloped 1/4 inch / foot, smooth and self-draining, are dry. If floors are not perfectly self-draining, they are easily drained with squeegees. Wet areas are clean and may be wet with sanitizer, with no pooling.
HYGIENIC USE OF WATER IN THE FACILITY
Water temperature and pressure meet requirements at peak usage times. Hoses, nozzles, and mix stations are functional and routinely monitored/maintained. Locations and hose length ensure accessibility to all process areas.
INSTALLATION OF EQUIPMENT
Floor/equipment junctions are mounted, grouted in place and are accessible for cleaning. Equipment legs are designed to minimize moisture entrapment (no hollow tubing). Other equipment has solid pin legs with a rounded tip to minimize moisture.
PLACEMENT OF EQUIPMENT IN FACILITIES
All food processing equipment is positioned away from adjacent walls or other obstructions at a minimum 3 feet to allow for cleaning and inspection.
PLACEMENT OF HAND WASHING STATIONS
All hand wash sinks are hands free. Hand wash and sanitizer stations are located for ready and frequent use in Zone 2 and 3 areas. Hand drying methods are consistent with hygiene zones.
PREVENTING WATER RELATED RISKS IN THE FACILITY
Water backflow protection is verified and documented via a quarterly audit conducted by trained internal personnel. An annual audit for verification is conducted by an outside certified service.
REPAIR AND MAINTENANCE OF EQUIPMENT AND FACILITY
Members of engineering, sanitation, food safety and a trained sanitarian are involved with all repairs for cooked/RTE zones with approval documented as a team for post lethality/high hygiene compliance to hygienic design requirements for cleaning and inspection.
Principles of Hygienic Design for Equipment
Sanitation Procedures During Construction
Containment Policy Considerations
Containment Decision Making Template
Maintenance, Construction and Demolition Containment Procedure
TEAM APPROACH TO IDENTIFYING DESIGN CONSTRAINTS
Company has a periodic maintenance and sanitation team that conducts routine equipment and infrastructure inspections to identify potential niche environments and harborage sources. Work orders are generated and executed to eliminate potential sources of Lm due to lack of access or difficulty of cleaning and inspection.
TRAINING IN HYGIENIC DESIGN PRINCIPLES
Corporate support is available for assistance with hygienic design compliance and if not- available support is contracted externally. Facility employs a trained sanitarian with knowledge of hygienic design of equipment and infrastructure.
UTILITIES TO PROMOTE HYGIENIC DESIGN
Positive and negative air pressure is created through the use of automated control systems to compensate for changes in the room air pressure. Direction of airflow from the post lethality/high hygiene areas to less sensitive areas.