Food Engineering

Goodbye, elbow grease

March 6, 2006
The business case for automating plant sanitation has always included soft savings, though the value of extending production runs between sanitation shifts is appreciated by food and beverage processors. But even the soft dollars are acquiring a harder edge as customers and regulators increase pressure for documentation that the soil removal and equipment sterilization steps that are supposed to be done do, in fact, occur.

Spray nozzles clean eggs being conveyed to a cracking machine. Albumin from prematurely cracked eggs presented foaming problems that were engineered out of the automated system. Source: Central States Industrial.


Clean-in-place (CIP) systems continue to spread beyond the dairy and brewery sectors, with meat and poultry processors and soft-drink bottlers actively looking for ways to transfer CIP concepts to their own operations. The need to control pathogens, allergens and other sources of cross contamination has increased interest in automated systems. Automation also provides an opportunity for data collection to validate procedures and optimize the use of cleaning and sanitizing chemicals. "The cost of cleaning chemicals is a major issue for food processors," points out Steve Cook, food engineering manager at Central States Industrial (CSI), a designer and fabricator of stainless-steel piping systems.

While many cleaning and sanitizing chemicals are available, cost and restrictions on discharged wastewater pose challenges to plant operators. More economical alternatives are needed, and few, if any, cleaners are as economical-or common-as salt.

Electrolyzed oxidizing (EO) water is a cleaning technology that has been applied to sushi, eggs, poultry carcasses and raw vegetables. Researchers at Penn State University have applied it as a cleaning and disinfecting agent in milking systems. Using an EO water generator from Atlanta-based Hoshizaki America, they created alkaline and acidic solutions from simple salt and compared the sanitizing effectiveness to chlorinated detergent and a weak acid in CIP piping. The generator contains positively and negatively charged electrodes in an electrolysis chamber separated by a membrane. The cathode side generates a solution with dilute sodium hydroxide, while the anode side creates a solution with high oxidation-reduction potential (ORP). When used in combination, the solution combines high ORP, chlorine and low pH to deliver powerful antimicrobial cleaning.



Researchers fabricated this pilot milk-transfer system to test the efficacy of electrolyzed oxidizing water for CIP sanitizing. Source: Penn State University.

"Instead of buying expensive chemicals, storing them and then handling them, you would simply buy a truckload of salt," explains Ali Demirci, an associate professor of agricultural and biological engineering who coordinated the research project. "This solution is a lot more environmentally friendly: the worst thing you get is sodium chloride at 0.1 percent. It could be used in any kind of CIP sanitizing equipment and would completely change the protocol." Besides reducing chemical costs, EO cleaning requires less energy because water only has to be heated to 60

To produce 216,000 lbs. of liquid egg a day, Center Fresh Egg Farm relies on a candling station a bit more modern than, say, an actual candle. Source: Central States Industrial.

Lend a hand

Manufacturers intent on removing the elbow grease from the sanitation process are more likely to work with JohnsonDiversey's Rock Hill, SC, office, where Cliff Vaughn hangs his hat. Vaughn is the engineering project manager for the company's North American food group. His projects have included an actuated manifold that swings into place to clean hard-to-reach areas between filler valves and bowls while the machine is in operation. The mechanical device was created because mold tended to form in those areas with other automated cleaning devices, tempting operators to try to wipe the area clean while the filler was in motion. "In the six years since I developed that, I'm sure I've saved a hand," says Vaughn.

Filler OEMs began incorporating automatic valve cleaners in European beer fillers a dozen years ago, with US breweries following a few years later. Second generation systems now are being incorporated during equipment fabrication.

A more recent development is external CIP for beverage operations. "Five years ago, there was only a handful of applications, mostly in soft drink bottling and brewing," says Vaughn. "Now we're engineering external CIP systems for other beverage companies and looking for ways to make the enclosure smaller."

Essentially a clean room erected around a filling machine, the setup includes high-pressure water nozzles to deliver foamed sanitizers and rinse solutions to the exterior of the equipment during a CIP cycle. Enclosures of 9,000 cubic feet or more used to be built; by downsizing the space, less water and fewer chemicals are needed to achieve the same results.

External CIP without the walls was the assignment for Project Engineer Richard Gardner of Spraying Systems Co.'s Hudson, NH, office two years ago. A maker of potato salad and other specialty items was bringing a new 80,000-sq.-ft. facility on line and wanted to automate the fogging of food-contact surfaces with quaternary ammonia and chlorine solution. Besides the labor involved, manual fogging resulted in uneven chemical applications, resulting in food-safety risks or washdowns and recleaning to remove excessive chemicals. Gardner divided the plant into 25 zones and mounted 47 atomizing nozzles below the ceiling to fog each area.

The control system regulates a dosing pump and flowmeter, calculating the proper amount of chemical concentrate to mix with the volume of water flowing through the meter to deliver a mist with 800 to 1,000 ppm of sanitizer to surface areas. "If you switch from a 1 percent to a 0.5 percent solution, the pump knows it has to work twice as fast to deliver the right solution," says Gardner. "The calculation is complex, but it's intuitive for the operator." The controls are tied to a plant-wide HACCP validation system.

Chemical and water savings also result from automated surface cleaning (ASC) such as conveyor-belt systems, though it can take years for the reductions to generate a return on installation costs. "Where we see the best return on investment is the ability to extend production runs between sanitation shutdowns," notes JohnsonDiversey's Vaughn. Plants have pushed cycle times from 24 hours to 48, then 72. "At 96 hours, you've gained a whole extra day's production a week," he says.

"Validation with swab tests allows you to extend the run time because you're able to document that your equipment was clean," adds Vaughn. "I don't think 120 hours is necessarily the limit to how far the industry can go, though as a practical matter most systems won't run that long without an upset."

ASC is a concept primed for growth, believes Rick Nelson, manager of project engineering in Ecolab Inc.'s South Beloit, IL, equipment fabrication facility. Customer expectations are forcing some processors to migrate from manual cleaning and sanitizing to ASC. Chemical concentrations, spray pressures, water temperatures and other variables are easily collected from PLCs and integrated into HACCP reports. Nelson cites a cheese-plant client who wants to make the transition to an ASC controller to eliminate the problem of incomplete handwritten logs and validate the cleaning of critical control points. "Currently if they get an audit request from a key customer, they could risk having the order rejected," he points out.

Standardized ASC units for belt sanitizing can satisfy simple cleaning tasks, such as infeed conveyors to a filler or other CCP. For plant-wide systems, the engineering becomes complex. Retrofits are much more likely than greenfield installations, and boring holes every four feet to accommodate spray nozzles adds significant cost. "In some cases, it may involve more piping than you have in a CIP system," says Nelson. To keep capital costs in check, a modular design is often appropriate and effective. A project for a sports-drink bottler benefited from a modular approach. "Sanitation was taking almost an hour between changeovers, and they were doing a lot of changeovers," he recalls. "We installed a modular design that was able to take cleaning times down to 14 minutes."

Dramatic efficiency gains are made possible by equipment designs that facilitate self-draining and leave surfaces exposed for cleaning to a microbiological level. Sanitary design standards promulgated by the American Meat Institute and promoted at seminars for dairy, meat and poultry corporate managers dovetail with ASC. "AMI seminars do an excellent job of advancing sanitary design for equipment that couldn't be automatically cleaned before," says Nelson.



A central system with adequately sized tanks, pumps, filters and heat exchangers simplified CIP for three egg-wash lines at Center Fresh Eggs. Source: Central States Industrial.

Foam cleaning

Recirculating CIP sanitizing water as a pre-rinse is a common economy, provided soil loads are moderate. Residual chemicals and the heat in the water are too valuable to flush down the drain before wringing out all possible value. Still, CIP systems require multiple tanks and huge volumes of water. Some equipment manufacturers are rethinking CIP and opting for a single-pass approach coupled with foam.

Pressurized air mixed with detergent optimizes the automated cleaning system in FMC FoodTech's spiral freezers. "Everything inside the box is considered a food contact surface," according to Ingmar Pahlsson, who manages the spiral freezer business from Helsingborg, Sweden. That includes the evaporator, which can have up to 3,000 square meters of surface area. A recirculation system would require 14,650 gallons of water to clean the zone; by using low-pressure foam and a rinse cycle, water use is 5,200 gallons. Less water simplifies waste removal: the foam collapses and dilutes into the water, and gravity carries it down sloped surfaces to drains. Self-priming pumps that can overcome cavitation issues from entrained air are unnecessary.

Foam-and-rinse won't remove dense particles such as chunks of meat from the spiral's belt; manually operated high-pressure hoses are required. "When you have a lot of debris on the belt, the recipe system in the PLC enables processors to tailor the cleaning program," Pahlsson explains. After an initial rinse, operators leave and restart the sanitation cycle.

Listeria is the challenge organism in a freezer. Because of USDA's focus on listeria risk, US processors pushed FMC to offer steam cleaning as a freezer sanitation option. "Over the past year-and-a-half, that is a customer-driven demand we've responded to," says Pahlsson. The fully-welded enclosures accommodate steam sanitation, but steam at 180

For more information:

Steve Cook, Central States Industrial, 800-654-5635, stevec@csidesigns.com

Rick Nelson, Ecolab Inc., 815-389-8132, rick.nelson@ecolab.com

Ingmar Pahlsson, FMC FoodTech, Ingmar.Pahlsson@fmcti.com

Frank Sack, Hoshizaki America, 770-487-2331

Cliff Vaughn, JohnsonDiversey Inc., 803-327-1275, cliff.vaughn@johnsondiversey.com

Ali Demirci, Pennsylvania State University, 814-863-1098, axd29@engr.psu.edu

Richard Gardner, Spraying Systems Co., 603-595-8819



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