To better serve Eastern U.S. markets with its packaged fresh vegetable salads, Dole Value Added Products last year started-up a new $30 million, 156,750 sq.-ft. plant on a 40-acre site in Springfield, OH.

Unlike Dole's salad plants at Yuma, AZ, and Soledad, CA, (Food Engineering's 1995 New Plant Of The Year), which semi-annually rotate production equipment for proximity to seasonal raw materials, the Ohio facility operates year-round as well as around the clock. Three manufacturing shifts operate five days per week, with shipping continuing on weekends.

Currently, about 300 employees convert about 200,000 lb. of 14 different raw vegetables per day into ready-to-eat salads in 38 SKUs, all retail packages. "We produce every SKU every day," says Plant Manager Lenny Pelifian. This typically means five major changeovers (films, packaging machine tubes and washdown) and 21 minor changeovers (film only) per day.

The plant doesn't produce every SKU in the Dole salad line. However, it receives finished products from Soledad and Yuma for further distribution. "We manufacture about 70,000 cases per week, with ability to ramp-up to 150,000 cases per week in the future," Pelifian says.

USDA standards

From groundbreak to startup in March 1998, the Springfield plant was executed as a fast-track design/build project in just 11 months by a team combining engineers from Dole and The Dennis Group (Springfield, MA), which had earlier partnered with Dole to execute the Soledad and Yuma projects.

Like Soledad, the Springfield plant is designed to USDA-equivalent sanitary standards. All process equipment is made of stainless steel with continuous welds and open construction. Interior wall panels are made of insulated epoxy-coated aluminum. An employee/ utility corridor minimizes potential cross-contamination between process rooms and provides a thermal break between process rooms and offices, reducing condensation. Plant temperature is maintained at 33-36¿ F to minimize product degradation and extend shelf life. Entrances into process rooms are equipped with antibacterial hand-wash stations and boot baths.

The plant was also designed for expansion, allowing space for additional packaging lines.

Process profile

Raw vegetables are converted into packaged salads no later than 36 hours from receipt on a first-in, first-out basis. Fresh vegetables are received mainly from Dole facilities at Soledad or Holtville, CA, (which supplies Yuma) 24 hours per day, six days per week, via refrigerated trailers which typically reach Springfield in 36 hours. Iceberg and Romaine lettuce are vacuum-cooled or hydrocooled before shipping from California. Iceberg, cabbages and carrots are received in 450 to 600-lb. corrugated totes, other vegetables in 50 to 60-lb. cartons.

Totes are fork-lifted to automated dumpers supplying conveyors feeding three manual trim lines and an automated trim line. Cartoned vegetables are manually dumped. On the manual lines, workers remove wrapper leaves, defects and cores from lettuce and cabbages, which proceed to Urschel TranSlicers for cutting. Cross conveyors link the three lines to add cut vegetables as needed for specific salad varieties. Ultrasonic sensors measure product depth on conveyors and control the addition of minor vegetables to achieve appropriate mix ratios.

Blended salads move via FMC horizontal-motion conveyors into the first stage of a triple wash system. First, the blend is sprayed with chlorinated water and dewatered in a Key Iso-Flow vibrating conveyor ("shaker"), which moves the blend into a second tank. The water is screened for fines and returned to the first tank. In the second tank, the blend is twice sprayed with chilled water containing a lower chlorine concentration, then dewatered again.

The automated trim line shreds and blends red cabbage and carrots for "Classic Mix" salads and includes inspection conveyors, cutting machines, a closed-loop chilled wash and chlorination system, dewatering shakers, a screening system, a non-chilled recirculation loop and an augur blending system actuated by ultrasonic sensor which adds cabbage/carrot mix in the specified ratio.

Salads are dispensed via vibrating conveyors into 300-lb. capacity stainless steel baskets on three dryer lines. The baskets are hoisted into centrifugal dryers to spin out excess water.

Baskets elevate to dispense salads onto Iso-Flow metering conveyors supplying four Yamato combination scales atop three single-tube and one twin-tube Hayssen vertical form/fill/seal (VFFS) bagging machines. The conveyors, of "double-stack" design, can each supply two packaging systems, eliminating the need for additional downstream equipment when new packaging lines are installed. Pouches containing dressings, seasonings and croutons are manually deposited into scale collection cones. (Automated pouch indexers are being integrated.) The VFFS machines package salads at 55-60 bags per tube per minute in 12 different bag sizes. The bags are made of films with varying oxygen transmission rates. Filled bags move through metal detectors to four manual cartoning lines supplied from box erectors overhead. Filled cartons are bar-coded via ink jet, conveyed to a palletizer, stretch-wrapped and fork-lifted to a 52-pallet order-pick area.

Water carrying vegetable waste (culls) flows through grinders and rotary-screen drums, where water is separated from waste. Water is recycled for cleaning floor drains, then routed to an equalization tank for measured release to the municipal wastewater system. Culls are dewatered through a screw press and conveyed through chutes into trucks operated by a local compacting service.

An Opto 22 system distributes process control to about 1,500 I/O points through four controllers integrated with PCs and touchscreen human machine interfaces (HMIs). The system integrates with a database linked to Dole headquarters at Salinas, CA; with the bar-code system for tracking shipments; and with Datastream software, which schedules and records maintenance and repair activities.

Incoming vegetables are visually inspected for spoilage and physical defects, and samples sent daily for microbiological analysis to Siliker Laboratories in Columbus, OH. The plant operates a HACCP program with critical control points including swab tests for plant hygiene; on-line chlorine analysis; and wash-water temperature. Statistical process control (SPC) is applied for continuous improvement of packaging specifications and salad-mix ratios.