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.
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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.
Curds …
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.
Highest Tech
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.
Quality Control
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“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
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