When designing a plant to assure petfood safety, it is important that planning the layout of the facility includes not only the rooms and equipment but also product flow and people traffic patterns.
With increased scrutiny by consumers and regulators in the US, European Union and other regions, ensuring the safety of petfood products is crucial. For petfood manufacturers, food safety starts at home—in this case, the manufacturing plant, especially when it is being built or retrofitted.
“Building quality and safety into the finished product should be a primary focus for petfood manufacturers that want to build a new plant or retrofit an existing one,” says Tim Hartter, director of Corporate Project Services. “This means getting things right from the beginning.”
The first focus should be the location of the facility, Hartter adds. “The size of the site should allow for all buildings, parking lots, access roads and future expansion. Adequate drainage of water should also be a priority. Where possible, the facility should be located in an area free of industries that attract vermin. The location should also be free of odors and airborne particulate matter that may be produced by neighboring industries.”
After the proper site has been selected, it is important that planning the layout of the facility includes not only the rooms and equipment but also product flow and people traffic patterns, Hartter says. “Inadequate control of the flow of people through product operational areas is one of the most serious risks for production contamination. People often act as carriers and bring from the outside contaminants such as dirt, debris and vermin, which are ideal vectors for microbiological growth and can directly and indirectly contaminate product.”
To prevent contamination, Hartter recommends establishing zones within the facility, limiting access of personnel from one zone to another. For example, personnel working in the raw material storage, mixing and grinding zone would not access the process zone or the packaging/warehouse zone, and vice versa.
For another holistic view of designing petfood safety into your plant, experts at Horizon Systems suggest considering five interactive food safety themes (Figure 1):
Ensuring food safety in a petfood manufacturing plant requires strict attention to five interactive themes, especially to the weakest link in the plant.
According to Horizon Systems, a sanitary plant design would look similar to Figure 2, in which the zone matrix is organized around moisture activity (dry vs. wet), material logistics (raw vs. ready to eat), pathogen activity (hot, intermediate or cold) and process control (control points, CCPs and clean-break points).
Experts at Graintec, which specializes in designing plants with a focus on hygiene and food safety, offer these recommendations:
Cross contamination is one of the most common problems in food processing facilities. This can arise from a variety of sources, Graintec says, including residual feed from bucket elevator feet, feed mixers (a ribbon mixer with liquid addition represents the biggest risk) and incomplete emptying of bins and hoppers due to problems like bridging and hang-ups. Other causes of cross contamination, Graintec adds, can be leaking mixer gates, other gates and outlet slides, delayed return of dust to the production line (from central dust aspiration filters, hammer mill filters, etc.) and various dust emissions, including dust adhesions inside conveying equipment, bin and hoppers.
Hartter also suggests looking at poorly designed and operated air handling and dust extraction systems as sources of cross contamination, along with inadequate procedures for personnel and equipment. Establishing positive air pressure zones to assure that contaminates are not introduced into the product should be a major consideration during the design of a food processing facility, he says. “Properly designed air handling systems will control airborne particulates and odors, minimizing the risks to products from airborne contamination by infectious pathogens such as Salmonella and from spoilage micro-organisms such as yeast and molds.”
In considering plant design and safety, Graintec offers additional food for thought:
Collaborating on plant design for food safety
For the full article by Jerry Rudie of SSOE Group (see sidebar, p. XX), visit www.petfoodindustry.com/45983.html.
Alliance of expertise is key to petfood safety
By Jerry Rudie
The most efficient and fail-safe way to achieve a technically sound, food safety solution for petfood manufacturing is through early collaboration and careful integration of decisions among the process engineer, systems integrator and equipment vendor. Discussions among this key trio must begin with a clear understanding of the “what, where and how” pertaining to the petfood being processed.
To ensure that location and storage of raw materials, movement and handling of the ingredients and processing procedures are performed via contaminant-free methods, preventive controls must be addressed collaboratively. A walk-through of the environment from which the raw ingredients are transported can determine what safety practices are in place.
When the engineer, integrator and vendor perform a hazard analysis, they can collectively determine ways to prevent, eliminate or reduce any hazards that are likely to occur before, during and after processing. For instance, the strategic placement of sensor and surveillance devices could signal problems well before disaster occurs. Once preventive controls are addressed, next steps can begin with designing the facility layout, installing the right equipment and integrating systems accordingly.
Collaboration on optimal process flow, from incoming raw materials to the finished product, is critical. Consider the extrusion equipment. Whereas the process engineer might provide for minimum equipment clearance, discussion with the systems integrator might show that additional space is required to facilitate use of lifting mechanisms for the die, as well as space to maneuver a forklift to move or replace the extruder itself when necessary. Consultation with the equipment vendor might further suggest placing the extruder three stories above the floor to avoid the need for an airlift at the end.
When the three experts collaborate on the best solution, multiple site and facility design issues are resolved early and without redesign, layout improvements are detected early in the design phase and flow efficiency and food safety are greatly improved.
Jerry Rudie, PE, PMP, is a senior project manager at SSOE Group.
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A sanitary plant design includes a zone matrix organized around moisture activity, material logistics, pathogen activity and process control.
The size of the site for a new petfood plant should allow for all buildings, parking lots, access roads and future expansion. Adequate drainage of water should also be a priority.
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