Facility Design and Product Flow

Processing, packaging, or packing of food takes place in diverse locations and physical structures and on many different scales. The overall design of the facility, from receiving area to shipping dock, is an important consideration in eliminating opportunities for chemical, physical, and microbial contamination. Both direct contamination and cross-contamination of product can be minimised with proper attention to the physical design, construction material selection, and facility traffic flow.

We recommend that the processing facility and its structures (such as walls, ceilings, floors, windows, doors, vents, and drains) be designed to be easy to clean and maintain and to protect the product from microbial, physical, and chemical contamination. For example, designing food contact surfaces to be smooth, nonabsorbent, smoothly bonded, without niches, and sealed would make these surfaces easier to clean and thus, would prevent the harborage of microbial pathogens.

Building

Both direct contamination and cross-contamination of produce can be minimised by giving proper attention to the physical design, emphasising proper product flow, using appropriate construction materials, managing facility traffic, and ensuring proper airflow. We recommend that facilities and staging areas be designed to facilitate maintenance and good sanitation practices so that contamination may be controlled throughout receiving, cooling, processing, packing, and storage operations. We also recommend that buildings, fixtures, and equipment be maintained in a condition that will protect fresh produce from potential microbial, chemical, and physical contamination.

The building should be designed so that incoming products never cross paths or commingle with finished products. This is a recommended practice for all processed food operations. Occasionally, the available space is limited, but physical separation of zones using walls or other barriers can achieve adequate separation. In addition, separate or segregated zones for chemical storage and mixing, and maintenance and fabrication shops are needed. 

A properly designed facility is important because the additional mixing, processing, and packaging steps that may be part of food processing increase the opportunity for cross-contamination. Pallets and bins coming directly from a supplier may also be a source of contamination. Proper facility design can significantly reduce this potential hazard. Finally, processed, but unprotected, products should not be stored in the same room location with dirty containers and pallets. For example, the facility should have sufficient storage room space to keep processed product, which is being held for later mixing and packaging, separate from incoming and stored materials.

1. External/Internal Structures

In general, we recommend limiting access to the facility and to its processing areas, providing adequate space for operations, ensuring adequate drainage of processing and wash water, installing food contact surfaces that are easy to clean and maintain, and designing areas and structures to protect the product and equipment from contamination.

In addition, we recommend the following practices:

• Adequately screening open windows, vents, fans, and similar features to prevent pest (insect, bird, rodent, reptile) entry

• Closing all exterior doors and entrances when not in use and ensuring an adequate seal when exterior doors and entrances are closed

• Properly constructing all walls, ceilings, windows, doors, floors, and overheads (e.g., pipes, air vents, and lights) and maintaining them in good condition (e.g., no cracks, rust, breakage, missing parts, or dips allowing puddles to form) so that they do not harbour pests or pathogens

• Designing properly sloping floors to drains (¼ inch per foot), and sealing and keeping them in good repair so as to provide adequate drainage

• Designing floor drains to prevent the accumulation of water in or around the drains and making drains accessible for cleaning

• Fitting floor drains with seals and grates capable of preventing pest entry

• Using floor flumes with caution due to the potential for water aerosol contamination of the room air and nearby equipment surfaces
  We recommend against the use of a floor flume transfer from the produce cooling and packing operation into or across an area housing fresh-cut produce operations.

• Constructing trench drains for automatic flushing

• Using under-floor drains in fresh-cut produce processing areas

• Designing collection areas for waste stream water to prevent product and equipment contamination

• Designing pipelines to avoid pipe and wall condensation from becoming a source of contamination
  Where overhead condensate cannot be prevented, we recommend that catch pans be utilized, and be cleaned and sanitized on a regular basis.

• Avoiding wood construction materials wherever possible
  If wooden equipment is used (including pallets), we recommend that the equipment be in good condition and well maintained so it is not a source of physical or microbial contamination. Non-wooden construction materials, such as plastic or stainless steel, are preferable for use in processing areas because they reduce the risk of microbial harborage and cross-contamination of the final product.

• Using protective guards for light fixtures to prevent broken glass from falling into product

2. Facility Layout

We recommend that a fresh produce processing facility be designed so that incoming raw products never cross paths with or are commingled with finished fresh produce products. This is a recommended practice for all processed food operations. Occasionally, the available space is limited, but physical separation of zones using walls or other barriers can achieve adequate separation. In addition, separate or segregated zones for chemical storage and mixing, and maintenance and fabrication shops are needed. 

Similarly, we recommend maintaining separate raw incoming product, in process, and finished product areas so as to prevent the potential for microbial cross-contamination. Adequate food safety controls, operating practices, and facility design can reduce the potential for contamination by using location and/or flow of humans, product, equipment, and air.

We recommend the following practices that use location to reduce the potential for contamination:

• Having restrooms that open into a location other than a processing area

• Locating the door to the outside in an area other than into a processing area

• Having a microbiology lab that opens into an area other than into a processing area

• Storing in-process and raw produce materials in different rooms

• Establishing dedicated cold rooms for raw product and processed product

• Locating hand washing and sanitizing facilities to facilitate regular and appropriate use by employees

• Locating a disinfectant foot foam, foot bath, or foot spray at all entrances and exits to all production and finished product storage areas.
  We recommend the following practices that use flow of personnel, product, equipment, or air to reduce the potential for contamination:

• Having short direct routes for both product and personnel flow

• Designing the plant for one direction of personnel traffic, product, and airflow

• Designing product areas to have traffic patterns that separate raw and finished product using either linear product flow (raw to finished product) or by a physical partition

• Using an air filtration system for central air distribution and airflow that is counter to product flow, so that filtered air moves with positive pressure from the cleanest areas (e.g., from packaging and finished product storage) toward less clean areas (e.g., the receiving area)
  We also recommend that air intake for the facility be located to minimize contamination of the intake air by:

• Keeping the number of entrances and exits to the processing areas to a minimum

• Restricting the movement of lift trucks, bins, totes, maintenance tools, cleaning implements, clothing, and people from receiving and storage zones to processing and packaging areas

• Colour coding bins, totes, clothing, cleaning implements, maintenance tools, and other items (e.g., blue aprons for receiving zones and red aprons for processing and packaging areas) may help achieve separation of traffic and thereby, minimise cross-contamination.