Lots and Lots of Mozz
November 1, 2004
Lots and Lots of Mozz
by James Dudlicek
Leprino’s Lemoore West plant stands as a symbol of quality and efficiency.
Perhaps the most amazing thing about the world’s largest mozzarella cheese factory is that it was built with expansion in mind.
Leprino Foods Co.’s Lemoore West facility in Lemoore, Calif., already can process 6 million pounds of milk a day, but the company is ready to double that if necessary. The $300 million plant, on a 100-acre site just off Highway 41 about 45 minutes south of Fresno, follows a linear design that allows production to be enlarged in increments of 3 million pounds. At some stages of production, expansion can occur within the existing walls, according to Bob Delong, Leprino’s senior vice president of production operations.
The plant turns that milk into more than 600,000 pounds of mozzarella and cheese blends every day — reportedly enough to cover about 800,000 pizzas — in several forms, including Leprino’s patented QLC® (Quality Locked Cheese) frozen shreds. The facility also manufactures lactose powder and whey protein concentrate.
With constant demand from Leprino’s many customers, including the country’s best-known pizzeria chains, time and efficiency are of the essence. “We can take a load of milk and have it on a pizza in six hours,” plant manager Steve Becker remarks.
Opened late last year, Lemoore West is one of nine plants Leprino operates around the United States and is a companion plant to the company’s Lemoore East facility a couple of miles away.
The Lemoore West plant is integrally linked by an access corridor that runs about 1,500 feet from end to end. That’s a lot of ground to cover, so let’s get started.
Taking it All In
The raw-milk supply for Lemoore West is managed by Dairy Farmers of America (DFA), which collaborates with California Dairies Inc. to ensure delivery obligations are met. The milk comes from farms in Tulare and Kings counties, dairies of some 1,000 head each in the richest milk production area in the United States.
The plant’s six drive-through bays can receive up to 1 million pounds of milk per hour from trucks arriving on a continuous basis. The bays are also used to load products like sweet cream for shipment across the country.
Upon arrival, raw milk is tested for temperature, pH and antibiotics. When it tests clean, the milk is offloaded into six silos, each with a capacity of 1.2 million pounds, or 150,000 gallons. Constructed on site, the silos rest on 6-foot-thick concrete footings, required to comply with California’s earthquake codes, says Mike Reidy, senior vice president of procurement, logistics and business development. Automatic sampling equipment draws raw milk for component testing.
Two agitators in each silo keep everything moving, with raw milk pumped out for pasteurizing followed by cleaning in place. “It’s a challenge to wash them because of their size,” Becker says of the silos. “You have to slowly heat them up or it could result in structural fatigue.”
Controlled by touch screens, two HTST pasteurization lines handle 182,000 pounds of milk per hour. Milk is than standardized to the desired fat level with an infrared system that analyzes the milk every 30 seconds for its fat-to-protein ratio, Becker explains. Sweet cream pulled off the raw milk is stored and sold.
The starter room features an HTST system linked to eight starter processor tanks and two starter media mix tanks. Starter, developed using a mother culture from the lab, is added to the pasteurized milk inline on its way to the cheese vats, where rennet is added.
A fully automated system controls the 20 cheese vats, 10 each under the guidance of two plant operators. The computer-integrated manufacturing system, or CIM, keeps a detailed record of every batch that passes through the vats, including lab results. Leprino developed the control system, which links operations at all of the company’s plants with the corporate office in Denver, from where everything can be monitored and process data easily analyzed.
After 20 to 25 minutes of ripening and setting, the cultured milk forms a gel-like consistency, Becker says. Once the gel-like mass is achieved, the curds are cut by the agitator blades. Curds are then cooked followed by a predraw of some of the whey from the vat. Finally, after a short period of settling, the remaining whey is pumped off.
“This is the ‘art’ part of it,” Becker says, “how long you have to cook it to get the right compositional level.”
Curds are then moved onto the dewheying and matting conveyor, or DMC. Distributed across a belt, the curds gradually form into a mat as whey continues to be expelled and acid develops. “This is one of the most critical steps. You do the fine-tuning here,” Becker says.
Drained whey is sent off to be clarified and separated for later use. The curd mat is transferred into a cooker-stretcher of Leprino’s own design, which heats the curd and continues to drain off liquid. “It melts the cheese and stretches it as if you were making it by hand,” Becker says.
Salt is added before the evolving cheese is sent to the block molders. Flowing through a pipe in a “molten” state, the cheese is conveyed into a hopper that feeds to an auger that pushes the cheese into the carousel block molder from below. The molder creates blocks of 6, 10 or 20 pounds, which are pushed out of their molds by metal fingers into a brine flume.
Cheese blocks move through an indexed brining system, which holds the blocks for up to four hours. Blocks of cheese are shepherded onto shelved racks that are lowered into the 150,000-gallon brine tank, which initially required 12 truckloads or 600,000 pounds of salt; additional salt is used to maintain brine salinity. With 80 6-pound loaves on each of nine shelves in each of the 28 racks, some 120,000 pounds of block cheese — about a third of the day’s production — can be brined at one time, Becker says.
Cheese that is not produced in block form can be directed into the production of Ribbon products or even further into IQF (individually quick-frozen) shredded products. These other cheese products start in a proprietary extrusion and brining process that transforms hot molten cheese into a nearly frozen ribbon after a 20-minute trip through the system.
The cheese comes off the extruder in a ribbon that’s 1/2 to 3/4 of an inch thick, Becker explains. The ribbon is cut into strips and stacked four high before it moves on for dicing and shredding. Strips are cut by Leprino-designed cutters into 3-inch squares, which are shredded or diced further to customer specifications. The shredding room has six lines but has ample room to expand with an identical setup alongside it.
Prior to final shredding based on customer requirements, the cheese passes through the first of four metal detectors and a checkweigher to document yields in a continuous process. A digital readout high up on the wall displays output through shred lines, which Delong says averages about 30,000 pounds per hour.
Cheese exits the shredder and travels up an inclined conveyor on its way to an eight-minute stay in Leprino’s patented QLC freezer, where the temperature of the shreds is taken to about –20 degrees F. This individual quick-freezing process locks in the cheese’s flavor at its peak, Reidy explains. “We’ve designed the cheese to perform the way an aged block would perform and locked in the quality by freezing,” he says.
Leprino’s QLC can be held frozen for at least a year and will perform as expected for several weeks after thawing.
IQF cheese is filled into a plastic bag lining a 15-, 25- or 30-pound case. The automated filler is divided into 20 different hoppers, which release the right amount of cheese for a given-size case. Each case is checkweighed, the bag is folded and the case is weighed again and sealed before passing through a final metal detector before heading off to be palletized.
In the palletizing room, kept at a constant 40 degrees F, cases are sorted into rows of four, then three rows per layer before being lowered onto a pallet in 12 layers of 12, totaling 144 stacked cases. The loaded pallet then advances to a stretch wrapper that spins the pallet to wrap the stack of cases in clear film.
Back at the block operation, trays are lifted out of the brine tank and the cheese is herded into another flume, which takes the blocks through the washer for a rinse-off before packaging. Conveyors channel blocks into two packaging lines at a combined rate of 27,000 pounds per hour.
A robot picks up six blocks at a time and drops them into formed film trays, which then pass through a sealer to receive the top layer of film. Once the film is cut, blocks are weighed and passed through a metal detector; some have labels applied, while others are wrapped in pre-printed film.
Robotic case loaders load eight to 10 6-pound blocks in each case before palletization. Another robot grabs and places a wooden pallet, then lays down a cardboard slip sheet before stacking cases two at a time for a total of 40 on each pallet, which are then stretch-wrapped.
Extruded cheese that’s not shredded is Leprino’s patented Ribbon cheese, which is sold for various applications including shredding by the customer. Ribbon cheese is packaged in wrapped blocks and 1,000-pound totes.
Palletized product is taken off to cold or frozen storage to await shipment by truck or rail.
… and Whey
Production of Leprino’s various whey products begins in the separator room across the hall from the cheese department. Whey from the cheese vats and DMCs is pumped to one of two raw whey holding tanks. These tanks are rotated and cleaned in place within four hours of use.
From the storage tanks, whey is routed first to one of six clarifiers to remove cheese fines that are returned to the cheese process. Clarified whey is then separated to remove final fat before pasteurization and ultra-filtration.
Skim whey is then transported more than 1,000 feet to the whey department at the other end of the plant, where it is pasteurized. In ultra-filtration, using two two-stage UF systems, the protein fraction is separated from the lactose/mineral portion, or permeate.
Protein is concentrated to 34, 60 or 80 percent before being evaporated in either a regular or instantized format and dried. The dried whey protein concentrate (WPC) powder is vacuum conveyed to one of four 75,000-pound storage bins before packaging.
The permeate fraction is evaporated to 60 percent solids and cooled in 14 10,000-gallon crystallizing tanks for 24 hours, using a specific cooling rate to produce the best yielding crystal size. The crystals are then separated from the mother liquor via two decanters, then further processed through a lactose refining system to increase the purity level desired for the final product. Next, the crystals are harvested from the refining liquid through two centrifuges arranged in parallel.
The lactose drying system uses a two-stage dryer. Dried lactose is milled to 100- or 200-mesh granulation and air conveyed to one of three 100,000-pound storage bins.
Both the dried protein and lactose powders can be packaged in 20-kilogram bags or bulk totes of up to 2,000 pounds. Two bulk-bag systems are employed, as well as one in-line filler and one carousel filler.
Behind the Scenes
Keeping a plant of this size and complexity running like a fine watch requires a solid infrastructure of utilities and maintenance. It also requires a heck of a lot of power and water.
The maintenance facility, including a shop area and spare-parts storage, is strategically located in the power/utility grid of the plant. Management of plant maintenance is assisted by a computer-based system used to generate work orders, projects and preventative maintenance activities for the facility’s 34 technicians.
Spare parts are on hand for practically every operation in the plant for immediate replacement to ensure production goes on undeterred. “When you’re dealing with a perishable product like milk, you can’t have any down time,” Delong says.
To supply steam for the multiple heating requirements in the plant, there are three 1,200-horsepower, natural gas-fired boilers with steam generation capacity of 41,400 pounds per hour each. “They’re all outfitted with state-of-the-art burners and air-handling equipment to meet the strict California emissions requirements,” Reidy notes.
In the air compressor and water filtration room, four compressors generate air while three booster pumps feed the facility with a constant supply of water, up to 6,000 gallons per minute. A 150,000-gallon water storage tank guards against water pressure surges from in-plant needs and city pressure fluctuations, and five continuously cleaning water filters remove particles as small as 10 microns from city water used throughout the facility.
For refrigeration needs, 20 ammonia screw compressors provide 12,850 horsepower for a rated 13,482 tons of refrigeration. Rounding out this system are six ice water chillers and 15 evaporative condensers.
And tucked away above it all is the plant’s “utilidor,” a utility corridor that runs the length of the plant and carries all vital utility pipelines.
All of Leprino’s proprietary technology is incorporated into the Lemoore West plant. The facility combines its innovative and efficient systems for cheesemaking and finishing to produce both traditional block cheese and its unique Ribbon and IQF products.
In addition to an efficient drying system that produces instantized whey proteins, the plant uses robotics extensively in its cheese and whey packaging systems. And for plant control, Leprino’s computer integrated manufacturing system allows the company to record and monitor all critical control parameters on a real-time basis.
“We believe our systems enable us to produce products with the greatest price-value relationships in the industry,” Reidy says. “Leprino employs unique and proprietary systems in starter making, fermentation, mixing, brining and shredding.”
Among these are the IQF freezing process, which dates to 1986; the “same-day dice” process; and brine-cooling technology that enables Leprino to eliminate lengthy intermediate aging and produces cheese with superior functional properties such as body, texture, shredding and melt.
“A lot of our innovation has come in response to customers,” Reidy says. “The whole issue of shredded cheese versus sliced cheese was in response to a customer saying, ‘This is what I’d like to have on my make table in my restaurant.’”
The company plans to continue to refine its mixing systems and will evaluate additional shredding capability, along with refining existing processes to maximize efficiency and flexibility.
“Everything we do starts with quality every day,” says Richard Barz, senior vice president of quality assurance, research and development. “Quality is twofold: Quality first and foremost is the safety aspect; the second part is performance attributes, what customers are expecting. These are the two general categories that we live and breathe every day.”
Internally, Leprino maintains a proactive quality control process for all its plants, built around comprehensive programs for quality systems and food safety established by the company’s corporate quality assurance group (QA). Each plant includes staff dedicated to monitoring production. Sampling and control-parameter monitoring are conducted continually each day.
Plant sanitation efforts are audited internally on a daily basis, as well as on the corporate level in conjunction with other quality systems to ensure compliance with company policy and regulatory requirements.
Technicians oversee the entire manufacturing process around the clock. Besides providing in-process checks such as metal detector, cheese temperature and scale checks, the technicians sample finished products including baked pizzas to perform simulated melt, stretch, handling and flavor tests.
Leprino technicians bake more than 6,000 pizzas per year at the Lemoore West plant as part of the company’s quality-control effort. The cheese’s browning, blistering and other qualities are tested against individual customer requirements. “We work with them to develop the uniqueness they want,” Delong says.
Meanwhile, in-process samples are tested for fat, moisture, pH and salt levels. Samples are held at various refrigeration conditions.
On the food safety side, Barz says, “we historically have been pretty aggressive as a general rule.” All Leprino plants operate under an extensive HACCP program supported by a number of prerequisite programs including ingredient quality assurance, sanitation and personal good manufacturing practices (GMPs). The entire program is under frequent review.
Environmental pathogen sampling from nonfood contact areas of the plant is done to ensure the process environment remains sanitary. All pathogen testing is conducted at Leprino’s lab in Denver to preserve the integrity of production environments. All product classes are tested at least monthly for pathogens, some as often as each product run.
Employing stringent allergen control, Leprino requires vendors to provide information about their processes and ingredient sources to guard against undeclared allergens. In addition, employees are trained to understand allergens, their control and their role to ensure food items containing allergens they may bring for themselves are limited to break rooms and offices.
Meanwhile, suppliers are qualified and certified by Leprino’s quality assurance group based on specific criteria including quality programs, food safety and GMPs. Suppliers must also offer proof of liability insurance, product guarantee, FDA plant registration and, if required, kosher or halal certification. Supplier approval is location-specific, so all manufacturing locations that supply material must be individually approved.
Suppliers that consistently meet specifications can earn the right to have their materials accepted based on certificates of analysis. Others must have materials tested prior to use.
Corporate QA and the internal audit group conduct frequent mock exercises to test recall capability, including all food ingredients, primary packaging and finished product. Various other audits include process compliance and food security procedures. Additionally, plant quality and food safety systems are routinely audited by customers, regulatory agencies and third-party specialists.
“We have well over 100 audits from outside companies in a given year,” Barz says. “Internally, we audit our factories from a corporate standpoint twice a year. Quality-control managers at each plant audit their facilities once a month.”
In regards to employee safety, Leprino maintains a comprehensive program supervised by three safety specialists in the human resources department at the Denver headquarters. These officials work closely with safety supervisors at each plant to ensure all programs are proactive and enforced.
Programs range from the comprehensive requirements of Process Safety Management required by the Environmental Protection Agency and OSHA’s Risk Management Program to videotaping of employee movements on the job to ensure maintenance of appropriate ergonomic conditions.
Plants employ safety observation teams to watch processes and detect any unsafe behavior. Safety results are reviewed daily in preshift meetings with further review at monthly plant-wide meetings to discuss achievements on safety incentive plans. A final review of safety results is completed during quarterly onsite reviews by senior management.
“Safety is obviously a very important factor in doing business,” Reidy says. “We’re proud of our safety record but we’re always looking to improve it.”
Training supervisor Stephanie Johnson says plant leaders also try to impress on employees the importance of safety at home. Delong agrees. “Safety’s a habit,” he says. “You can’t do it just at work or just at home.”
Clean, Clean, Clean
The term “spic and span” barely scratches the surface in describing the lengths to which Lemoore West goes to keep a tidy house.
Employees and visitors enter the production area through an air shower, which blows residual lint and particles from outer clothing. Wash stations are strategically located between all stages of production. In addition, hygiene barriers separate processing and packaging areas, as well as packaging and palletizing areas. At these points, people moving between said areas must wash hands yet again and strap on fresh booties before proceeding.
Furthermore, work areas are constantly being cleaned, scrubbed or otherwise maintained to a near-spotless condition. And as much effort as is expended on cleanliness indoors is devoted to what the plant sends out after the cheesemaking process is done.
Wastewater from both Lemoore plants is treated at the West plant’s innovative new facility before it’s released to the city’s wastewater treatment system, where it is ultimately used for crop irrigation. Some 2 million gallons of dairy waste from both plants are treated here daily. “With the strict environmental regulations California maintains, this facility is absolutely critical,” Reidy says.
The plant also employs a secondary holding and distribution system to utilize condensate generated by the permeate evaporator in cooling towers, boiler feed systems and CIP systems. This has reduced the demand for fresh water to the plant by about 600,000 gallons per day, while reducing the effective flow to the wastewater treatment plant by 500,000 gallons per day.
In addition, combustion emissions are as low as possible due to the application of new technologies to the steam boilers and WPC dryers, which can burn either natural gas or liquid propane.
Training is Crucial
Even with the high level of automation at Lemoore West, the human element is an indispensable component of production. “Training is absolutely essential to run this business,” Reidy says.,
Part of that is instilling in its work force the Six Leprino Quality Principles: customer service and satisfaction, continuous improvement and measurement, employee involvement in problem solving, personal and leadership development, productivity enhancement and ultimate establishment of Leprino Quality as a way of life.
Managed by the human resources department, employee training programs include standard operating procedures, safety, quality team meetings and task force meetings. The company credits a good part of its success to employee involvement.
That started from scratch two years ago for Lemoore West. “We started prior to start-up with a production supervisory trainee program, where we put supervisors out at other facilities to train on equipment so they’d be ready to help our folks when we started up the facility,” explains Debbie Vlotho, human resources manager. “We started that process with supervisors preparing to come in and help write procedures for this facility and train our new hires.”
Orientation for new employees includes three days of classroom training covering all aspects of plant operations. On the fourth day, they transition to the plant floor.
As part of classroom studies, Leprino employs an internally developed e-learning module system that takes new hires through a tutorial covering every piece of equipment in each stage of production.
“With all these people trained, they become the experts in their particular area of operations,” Reidy says. “We like to use our people to help solve our problems. They’re the ones who are most knowledgeable. So we’ve developed what we call the Leprino Quality Problem-Solving Process. It’s team-driven, with a heavy focus on continuous improvement — a hallmark of the company’s success. It’s been vital. It keeps people engaged and involved, to get the benefit of the knowledge of the people who are closest to the issue. It has been tremendously successful for us.”
The challenges were many in taking the Lemoore West facility from green field to working plant. The company reports spending more than $8 million just on workforce training before the first pound of cheese was produced, as a move toward ensuring success. Production scheduling also was a challenge, due to the variety of products made at the plant.
But it’s clear Leprino has surmounted these and other challenges successfully, and appears poised to take on whatever other demands are placed on Lemoore West. df$OMN_arttitle="Lots and Lots of Mozz";?>