“At the front end of the process, ingredient receiving and storage has been a major issue confronting the baker,” noted Brian Ivkovich, senior vice-president, Zeppelin Systems USA, Odessa, FL. “In recent years, added concerns of ingredient quality, contamination, safety, product liability, lot tracking and traceability have become increasingly important.”
Don’t forget worker safety, process efficiency, environmental issues and such secondary issues as proper silo cleaning, bag disposal and maintenance of automated systems, observed Bill Kearns, vice-president of engineering, Fred D. Pfening Co., Columbus, OH. To respond to all these concerns, bulk ingredient systems needed to become more reliable through the use of sensors and control technology. “Instead of a dozen alarm pilot lights on a control panel, systems now commonly have a hundred or more warning and alarm messages incorporated into operator screens, which call attention to problems before they reach a failure or shut-down condition,” Mr. Kearns said.
Two major challenges that bakers face involve creating systems capable of transporting various ingredients without residue or dust accumulation and with accurate, on-time portioning, noted Dominique Kull, manager, bakery supply systems, Buhler, Inc., Minneapolis, MN. A control system, he added, can alert bakers immediately if any ingredient is over- or under-dosed.
“If there are ingredient variations on the front end, you will not achieve consistent end product quality,” he said. “Food safety and quality are only assured with a sustainable ingredient handling system.”
Using sensor-controlled variable-frequency drives in critical locations can regulate systems that previously required frequent manual adjustment to keep running. Even some relatively low-tech developments such as permanently lubricated bearings and gearboxes have cut down on maintenance, Mr. Kearns suggested.
“Sifter manufacturers also have improved their machines by making them more accessible for maintenance and inspection and by developing more rugged drives and maintenance components that require less maintenance and lubrication,” he said.
SIFTING FOR CLUES.
Some of the biggest questions on the front end involve whether to sift prior to or after putting material into storage, noted Stuart Carrico, food process manager, Mac Process, Kansas City, MO.
“Some customers have a preference. Others are open to suggestion,” he said. “International food companies are generally slated toward sifting prior to storage. Some even go through metal detection prior to storage. The next largest challenge for bakers is anything having to do with meeting or complying with the National Fire Protection Association’s (NFPA) standards and how those standards may affect ingredient storage if not sifters or sifting of materials.”
When it comes to sifting, a greater number of bakers are leaning toward screening all dry ingredients, according to Mark Ungashick, executive vice-president, Shick USA, Kansas City, MO. For most ingredients, other than flour, bakers and other food producers generally rely on scalping to remove foreign particles and other substances such as paper and string. However, Mr. Ungashick said, scalping alone doesn’t necessarily prevent pest infestation that could cause a problem for the operation.
Mr. Ivkovich also noted that using both scalpers and screens can provide a multifaceted front for enhanced food safety in modern material handling.
“First of all, removal of impurities through the use of in-line coarse scalpers from a truck or rail car unloading systems is the first line of defense,” he said. “Secondly, active screening systems, with appropriately sized sieve openings, are used directly in-line in pneumatic conveying systems or trough gravity or atmospheric-pressure sifters.”
For bulk material handling, most bakeries prefer in-line sifters that are inserted directly into a dilute-phase pressure or vacuum conveying system vs. a gravity-flow sifter that works under normal atmospheric conditions and is not designed to accept air flow that will influence the sifting action.
In-line sifters rely on the ingredient handling system’s pneumatic air flow to transfer ingredients through the sifter. Unlike gravity sifters, they do not need blowers along with associated filter receivers, airlocks, surge hoppers and dust control to get the material to reach its destination, explained Bob Ricklefs, manager of sales and service, Great Western Manufacturing, Leavenworth, KS. However, if food processors need a sifter for precision particle grading or fines removal, then a gravity flow system is usually preferred.
“Not only are the initial system investment and installation costs substantially lower for in-line sifters, the ongoing operation, maintenance and sanitation expenses over the life of the system are reduced,” Mr. Ricklefs said. “Another important benefit is that the in-line concept gets the sifting protection as close as possible to the finished product with a minimum of additional costly equipment”
Great Western’s QA Series sifters, he added, incorporate sanitary features such as stainless steel contact parts with fewer welds, lighter-weight components and moulded neoprene gaskets that simply snap on unlike previous, labor-intensive silicone gaskets. Moreover, depending on the model, the screen trays are made from stainless steel or from a single piece of aluminum. Such a design, Mr. Ricklefs said, eliminates woven wire backwire as well as fasteners, gaps and crevices.
For personal safety, wrap-around guards with an integrated pneumatically operated safety circuit stops the sifter if an operator tries to access it.
MORE LINES OF DEFENSE.
Sifters or in-line magnets can be placed in various locations along a conveying line to prevent any foreign matter from getting into the process, according to James Toole, sales application engineer, KB Systems, Bangor, PA. “Our centrifugal in-line sifter also operates quietly and safely, with no need for additional guarding,” he said.
“This is very useful when a unit is located on or around the production floor. In addition to that, each unit is designed to minimize production downtime with the use of an easily removable screen assembly,” Mr. Toole said. “The majority of systems that KB has installed are closed-loop. This type of system will generally contain any dust and alleviate the area of hazar-dous materials.”
Along with chute magnets or in-line sifters, an electronic metal detector with an automatic diverter that detects ferrous and nonferrous metal can provide yet another layer of defense, Mr. Ivkovich said.
By automating ingredient handling, bakers can better track ingredient usage as well as monitor and control any problems if they occur.
“You can isolate a bad batch of flour with the use of inventory control and lot tracking devices,” Mr. Toole said.
Specifically, Mr. Kearns suggested, automation improves traceability documentation of batch numbers because the system records times and the types of ingredients without depending on operators to manually write down what’s used.
Reducing human error throughout the process is the best way an automated system can improve food safety, Mr. Ungashick said.
“The less an operator directly interacts with the weighing and handling of ingredients, the greater the chance that the finished product will be safe for consumption,” he noted.
Several food companies are pursuing what Mr. Carrico calls “no touch” models for handing all ingredients for their products. “We believe that as food safety and other forces such as NFPA continue to impact our customers, they will start looking harder at removing human intervention,” he said.
Automating all material handling, especially minor and micro ingredients, might not be affordable for some bakeries either because the systems are too expensive or because of an inadequate return on investment.
In such cases, companies such as AZO, Memphis, TN, offer systems such as the modular-designed ManDos, which can weigh, record, document and feed minor and micro ingredients into the mixing process.
“These are weighing stations in which the operator can guide and weigh the ingredient manually and that can be controlled by barcodes registered as [ingredients] are delivered to the [mixing] process,” noted Walter Sonntag, division manager marketing/documentation, AZO GmbH & Co., the parent company based in Osterburken, Germany.
RATCHETING UP CONTROLS.
Automating material handling reduces the potential for exposing ingredients to contamination. “Bulk systems, in particular, eliminate potential contamination from paper, plastic and glue from bags and boxes,” Mr. Kearns said. “In addition, they are less subject to rodent and insect contamination than ingredients stored on pallets in warehouses.”
Installing controls to avoid cross-contamination can reduce allergen issues.
“Instrumentation and control systems can be employed to provide interlocks and preventive measures to keep personnel from sending ingredients to the wrong destination,” Mr. Ivkovich said. “If a problem is detected in the finished product, whether due to operator error or supply chain issue, it is easier to track and locate the source of contamination if the control system is equipped with the right tools.”
To provide traceability and quality assurance, many companies offer a variety of software packages. Zeppelin’s PRISMA system, for instance, provides formula management, production scheduling, batch logging and lot tracking and can be integrated with a company’s manufacturing resource planning (MRP) system to provide a global ingredient management system, Mr. Ivkovich said.
Likewise, Shick has developed its automated ingredient management (AIM) system that combines ingredient and formula management with production scheduling, data collection, lot tracking and reporting, user security and business system integration, Mr. Ungashick said.
Buhler’s WinCoS.r2, its newest generation of plant automation, offers a self-learning batch system designed to improve efficiency and accuracy, according to Mr. Kull.
To ensure food safety, the best defense ultimately starts with a proactive offense by providing the necessary controls at the beginning of the process.