Production Tech: From the ground up
Apposite walls and floors are essential in keeping meat- and poultry-processing facilities safe and clean.
Regardless of the money poured into sanitation maintenance programs, some physical environments make it difficult to achieve the desired results. The effectiveness of sanitation maintenance programs can be influenced at a more fundamental level â€” plant layout and design (especially when it comes to its floors and walls) â€” that pays attention to sanitation details. Sanitary requirements need to receive due consideration from site selection through final operation, because engineered sanitary features throughout a plant can improve the quality and safety of the finished product. Good Manufacturing Practices (GMPs) engineered into plant design can reduce maintenance and the probability of product contamination.
Selecting the appropriate flooring system is best achieved by having an understanding of the properties of concrete, the operating environment and the conditions of installation and use. As concrete is a porous substrate, moisture in the form of water vapor can migrate from below the slab to the area above the slab, depending upon the temperature, air movement and humidity. Thus, it is essential that an impermeable protective coating be applied to the concrete not only to prevent the migration of chemicals in and through the concrete, but also any moisture from traveling out of the concrete.
To serve the unique needs of the meat and poultry industries, suppliers offer environmentally friendly coatings solutions engineered to meet all of the needs of USDA-inspected processing plants â€” floor to ceiling, front office to tank interiors. With the many issues concerning pathogens, there are several additives available to coating manufacturers which will inhibit any bacterial growth.
Along with food safety, worker protection is definitely an area of concern for meat and poultry processors. To that end, slips and falls are a major liability for any company, especially where wet conditions and residual fat, for example, provide opportunities for accidents. Anti-slip coatings are also used on ramps and docks to provide traction for forklift traffic.
Above all, sanitation is the critical issue for flooring in modern food-processing plants. A smooth finished concrete floor at the proper slope, and featuring a sprayed or brushed-on sealer, is said to be best for normal environments. Various surface finishes, quarry tile, acid brick, troweled-in surface hardeners, and polyester epoxy protective coatings can combat the damaging effects of the environments expected. Regardless of the quality or cost of the construction of the floor and/or finish, timely maintenance will preserve the desired sanitary qualities.
Surface thickness will be driven by the need to provide thermal-shock protection, resurfacing requirements and the traffic conditions expected. In general, chemical- resistant systems are resin rich and utilize aggregate to build thickness, decrease the Coefficient of Linear Thermal Expansion (CLTE) of the system, and provide abrasion resistance where required. Food-processing plants also have the added element of live steam and/or very hot water in the cleaning process.
Here, additional analysis of the system’s CLTE and the flexibility of the bond interface to concrete is required. Some resinous flooring will expand at 10 times the rate of concrete or steel. This is also true of resinous coatings on a block or concrete wall. Through fundamental improvements and modern advances in resin formulation and extensive development over the past 15 years, cementitious polyurethane technology has been able to formulate systems with a high-resin content and low viscosity that both flow and level better. This has enabled the origination of heavy-duty flooring compounds that have zero volatile organic components, are highly chemical resistant and non-porous, and are now able to be installed more efficiently and effectively.
Prestressed concrete panels usually can span between building floors without intermediate support from girts that can generate ledges. Certain PVC or fiberglass-insulated panels will resist most chemical environments, but the numerous joints, the potential for damage due to abuse, and the voids between the fascia and the liner sheet make the system less desirable than concrete panels.
Foam-filled insulated sandwich panels with fascia and liner sheets of stainless steel, aluminum and painted steel can eliminate the cavity problems associated with insulated panels. But, if left exposed on the top or bottom of the panel, some foams can attract ants, which can use the foam as an excellent tunnel medium. Foam-filled sandwich panels can also span larger distances, and eliminate or reduce girt support framing.
Glazed tile is said to be an ideal wall surface in any foodgrade facility. Although more costly, these walls are chemically resistant, attractive and easy to clean. On the flip side, laminated block provides the glazed-tile look and performance and is more economical than glazed block, but may be subject to chipping and delamination due to temperature shock. Wall penetrations and the ends of the wall should be properly grouted and sealed off. To eliminate ledges created by a tooled joint, the block should be placed with flush-type joints or slightly tooled joints. In addition, block walls typically require a special two- or three-layer polymer coating system to fill the voids in the block’s surface. The average thickness of such a coating should exceed 20 mils to obtain the surface desired.
In addition to any obvious debris on a floor, product can become contaminated by the flooring or microorganisms living in debris in tiny crevices in the floor. In order to avoid these sources of contamination, the following guidelines should be considered:
• Floors in areas where product is handled or stored should be constructed of durable, easily cleanable materials, and be impervious to moisture. Commonly used materials are concrete, quarry tile, brick and synthetic material.
• Floors should be installed and maintained to reduce the likelihood of cracks, depressions or other low areas that would accumulate moisture.
• Floors where operations are conducted should have a slip-resistant surface. Good results are obtained by using brick or concrete floors with abrasive particles embedded in the surface. Concrete floors should have a rough finish.
• Floors should be sloped to avoid puddles or depressions within the slope where water will stand.
Coving is used at the wall-floor juncture, column (post) â€” floor juncture, and equipment support-floor juncture to provide a smooth transition for ease of cleaning and inspection.
Coving in production and storage areas should include the following criteria:
• All seams should be tight-fitting and sealed to eliminate all cracks and crevices, which may shelter insects, vermin and microorganisms.
• The coving should eliminate any sharp angles that allow the accumulation of materials.
• Curbs should be provided to protect walls and wall finishes. Curbs should be high enough to protect the walls from pallets, trucks or containers used in the establishment. Coving should be provided at the base of the curb.
When selecting stairs, the following guidelines should be considered:
• Stairs should have solid treads and closed risers and should have side curbs of similar material.
Catwalks and Access Platforms
When installing catwalks and access platforms, the following should be considered:
• Catwalks and access platforms in edible product-handling departments should be constructed of materials that meet the same guidelines as flooring.
• Open grating should not be used for the flooring of catwalks and access platforms inside the establishment, particularly in production areas. Dirt and other debris from shoe soles can be scraped off by the grating and contaminate product, packaging material and equipment.
• Catwalks and access platforms should not be installed over production lines and processing equipment.
Interior Walls Including Posts and Partitions
To prevent product from becoming contaminated by contact with interior walls, care needs to be taken in selection of materials for the finished surface of walls. The following guidelines should be considered when selecting a finish:
• Interior walls, in areas where product is stored or handled, should be finished with materials that will make them susceptible to being readily and thoroughly cleaned and impervious to moisture. Examples of such materials are glazed brick, glazed tile, smooth concrete and fiberglass reinforced plastic (FRP).
• Walls should have a smooth texture, not one that is rough or uneven.
• Fasteners for wall covering material should be solid, smooth-headed, and not have recesses which allow the collection of foreign material.
The material that forms the basis for these excerpted guidelines is drawn principally from the technical knowledge and experiences used by the Food Safety and Inspection Service (FSIS) in making its prior approval decisions about the acceptability of facilities and equipment.
Source: USDA/NCDA&CS (United States Department of Agriculture/North Carolina Department of Agriculture & Consumer Services)