Cleanroom shapes the future of juice bottling
High speed, low-heat aseptic process enables juice company to introduce square bottles
By Paul B. Summers
It`s hip to be square. But to bottle its Clamato brand of juice in square bottles, Mott`s Inc. (Stamford, CT) engineers needed to design an aseptic cleanroom that would enable them to bottle the drink using a low-heat filling method. In July, the company opened its latest bottled-juice manufacturing facility in Tecate, Mexico, which includes a state-of-the art cleanroom. The company credits the cleanroom technology with enabling it to introduce the square plastic bottle. The 150-year-old company claims to be the first in the U.S. to use aseptic cleanrooms to produce bottled juice. Mott`s produces apple sauce and apple juice, as well as its Clamato, Mr & Mrs T bloody Mary mix and some Holland House cocktail mixers, and Rose`s and Mott`s Fruitsations brands in cleanrooms.
The Clamato bottling line is an unusual application of a cleanroom, which is usually dry. Not only is the cleanroom wet, but the juice is actually bottled within the cleanroom. This helps the company achieve the quality and appearance it wanted for its bottled juices. One of the major obstacles company engineers faced was that, while cleanrooms are typically used in a dry environment, Mott`s had to be constructed for a wet environment. Cleanrooms must control the humidity to avoid the tendency for bacterial growth. To maintain cleanroom standards, the equipment has to be washed down with a hose. To meet this requirement, the walls of a Class 100 filler cabinet, which operates within an 1,800-square-foot Class 10,000 cleanroom, were constructed with easy-to-clean stainless steel. Clean Rooms West Inc. (Tustin, CA) designed Mott`s cleanroom air system, keeping in mind these special requirements.
Mott`s first used a cleanroom when the beverage industry began switching from glass to plastic bottles in the early 1990s. To make its products stand out on the supermarket shelf and be more consumer and environmentally friendly, Mott`s wanted to use a distinctive square, plastic container with an easy-grip handle. However, to produce the new container engineers needed new technology, and a low-heat process that would require a cleanroom. They waited to switch to plastic bottles until the needed technology — high-speed machinery designed specifically for aseptic cleanrooms — became available on a cost-effective scale.
That equipment became available at the end of 1993, and was incorporated into the company`s first cleanroom in its Aspers, PA, plant where apple juice and Clamato are made. Mott`s second cleanroom opened at the Williamson, NY, plant in 1995 to keep up with the increased demand for plastic containers. Apple juice, Clamato, Mr & Mrs T, Holland House Cocktail mixers and Rose`s lime juice are bottled there.
The Tecate facility is the company`s third cleanroom, and it posed some unusual challenges. Company engineers had to contend with Class 4 seismic conditions in Mexico. Concerned about the possibility of earth tremors, they built the walls of the Class 10,000 area using stainless steel laminated panels with polyurethane foam in-between for thermal insulation. The panels will withstand greater vibration and flexing than more common types of construction, such as concrete blocks or laminated particle board.
While most beverage companies continue to use the standard “hot-fill” method of bottling — replacing glass with plastic bottles that could withstand the high heat — Mott`s switched to a low-heat filling process, which enabled engineers to use slightly different material for their square bottles. The hot-fill process involves heating the juice to a high temperature, pouring it into the bottles at about 190 degrees Fahrenheit, maintaining that temperature for three minutes to kill bacteria, and then cooling it. The low-heat process involves heating the juice to an even higher temperature (than 190 degrees F) to pasteurize it and then cooling it before filling pre-sterilized bottles.
Mott`s juice-filling and cleaning processes take place in a 320-square-foot Class 100 cabinet within an 1,800-square-foot Class 10,000 cleanroom. Air from the Class 10,000 area blows through filters in the overhead stainless steel air plenum, creating a laminar flow of Class 100 air down over the machinery and maintaining a temperature of 70 degrees Fahrenheit.
The bottles and caps enter the cleanroom on separate conveyors, after they have been sterilized with a liquid sanitizer to remove contaminants. The conveyor transports the bottles to the rinsing machine in the Class 100 cabinet, where they receive a final rinse with sterile water to remove any traces of sterilant and proceed to the filling and capping machine. Mott`s uses a process that heats the juice to pasteurize it prior to cooling in a closed, sterile system leading to the filling machine. After the bottles are capped, they exit the cleanroom into the general production area.
At the outset, by aseptically filling the bottles in a cleanroom, Mott`s had the advantage of greater flexibility in bottle design. In a hot-fill operation, a bottle`s sidewalls must be designed to withstand the contraction of the cooling process so they don`t buckle. Since Mott`s juices are cold filled, the bottle`s sidewalls could be molded into a unique handle to make it easier for consumers to grip and pour. The bottles are blow-molded in the plant.
To ensure an aseptic environment in the cleanrooms, Mott`s uses a clean-in-place and sterilize-in-place system, laser air-particle monitoring equipment, environmental swabs for surface sampling, special chemicals, and luminometry for detecting microorganisms.
The cleanroom operators wear protective cleanroom suits, gloves, boots and face masks. They enter through the Class 10,000 gowning room, where they receive an air shower for additional cleanliness before proceeding to the main area of the cleanroom.CR
Paul B. Summers is manager of engineering at Cadbury Beverages Technical Center in Trumbull, CT. Mott`s Inc. is a subsidiary of London-based Cadbury Schweppes PLC. Mr. Summers was responsible for the design, supply, and installation of aseptic product and container sterilizing systems for the Clamato line, and influenced the cleanroom design.
Key facts:
Air system designer: Cleanrooms West (Tustin, CA)
Designer/builder: Nielsen Billingham Builders Inc. (San Diego).
Size of facility: 320 sq. ft., Class 100 filling cabinet within an 1,800-square-foot Class 10,000 cleanroom.
Purpose of facility: To aseptically produce Mott`s apple juice and Clamato brand juice.
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Clamato`s new square plastic bottle.
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An operator in Mott`s Williamson, NY, plant cleanroom.