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From: Food Quality & Safety magazine, December/January 2009

A Cool Way to Clean

Dry ice blast cleaning is a cheaper, more efficient method

by Stuart Rabkin

Keeping food processing surfaces clean is a production manager’s main concern. Removing leftover food, grease, grime, and other residue from production equipment is critical for preventing bacteria growth and ensuring safe, high quality food products. As sanitation regulations become more stringent, labor costs increase, and the industry becomes more environmentally conscious, food companies are looking for new cleaning processes and solutions.

Caked-on dust, flour, grease, and oil, along with baked-on carbon, are some residues that are prevalent—and difficult and costly to remove from baking and production equipment. To ensure product quality, these residues must be removed frequently. Unfortunately, traditional cleaning processes, such as steam, water, and manual scrubbing, are slow, inefficient, and ineffective. Plant managers at a baked goods facility in Chanhassen, Minn., for example, found that it took a three-person maintenance crew nearly nine hours to clean their 30’ x 50’ machines. During that time, the cleaning crew could only remove 80% of the residue; the machine’s small parts and hard-to-reach areas simply could not be cleaned by hand. This scenario is not uncommon.

The food industry is heavily regulated. Some regulations concern water disposal and recycling sanitation issues. Others go as far as detailing the number of hours maintenance crews must devote to cleaning equipment. Any cleaning solution used by a food company must provide optimal cleaning results, while being safe enough to clean surfaces that come into contact with food products. The cleaning method used could impact the taste, cooking, processing, and overall quality of the food product.

One alternative to conventional cleaning processes used by food companies is dry ice blast cleaning, a process similar in concept to sand or bead blasting. Unlike sand or bead blasting, however, dry ice blast cleaning is not only safe for food processing environments, but also costs less, cleans more efficiently, and is more environmentally responsible.

Dry ice blast cleaning uses recycled carbon dioxide (CO2), a colorless, tasteless, odorless gas that is found naturally in the atmosphere. Dry ice blast cleaning is a process that accelerates dry ice particles through high-velocity nozzles to impact the surface being cleaned. The combination of kinetic and thermal shock effects breaks the bond between the residue and the surface being cleaned. The residue falls away from the surface and is easily wiped away. Because dry ice particles sublimate upon impact, dry ice blast cleaning eliminates the added cost and inconvenience of secondary waste treatment and disposal, as well as the worry of downstream contamination.

The solution is capable of removing—without chemicals or water—fat-based, protein-based, carbohydrate-based, and mineral salt-based soils, along with microbiological films like bacteria, yeasts, and molds, and lubricating greases and other insoluble soils. The grade of dry ice typically used in this cleaning process is equal to or greater than that of the dry ice used in the food and beverage industry, and the process has been approved by the Food and Drug Administration, Environmental Protection Agency, and United States Department of Agriculture.

Cost Savings

In many cases, in order to properly clean the mixers, cooling tunnels, conveyors, motors, panels, slicers, weighers, and dividers along the food processing and packaging lines, plants must stop production, shutting down and disassembling the machines. Stopped production means lost money, an issue compounded by additional costs, including labor, cleaning materials, toxic waste disposal, water usage, and reclamation systems.

At the recommendation of a sister plant, the baked goods company mentioned above turned to dry ice blast cleaning. During its initial cost analysis, the company determined that a dry ice blast cleaning system would save the plant more than $15,000 per year in cleaning labor and expenses alone, which proved to be an understatement. Dry ice blast cleaning provides a faster, safer, more efficient, and more environmentally friendly cleaning solution than other cleaning methods. It cleans equipment in less time, with fewer resources and manpower, as it increases productivity.

After initial use of the system, the company saw a 100% removal of all caked-on and baked-on residue, even from the small parts and hard-to-reach areas of the machines. In the food industry, the highest costs are associated with labor. The dry ice blast cleaning system requires only one worker and takes less than one-third of the time previously needed clean all the machines, changes that saved the company nearly 80% of its labor and resources costs. The company also expects an 80% improvement in product life versus water cleaning, eight years longer in the case of the conveyor chain, which has an average cost replacement of $100,000.

Efficiency, Environmental Benefits

In addition to being time consuming, inefficient, and strenuous, conventional cleaning processes, which use water, chemicals, and rigorous scraping and scrubbing can also damage production equipment. Replacing damaged parts results in further production stoppage and downtime.

Cleaning methods can severely alter a food company’s end product. Because food will likely come into contact with any cleaning agents used, all cleaning solutions and methods must be safe. To ensure product safety, the U.S. government has imposed regulations on where chemical solvents can be used—if they can be used at all—and on how water is used for cleaning and where it is disposed of following the cleaning process.

Food companies are also driven by concerns about toxic cleaning chemicals, which pose a health risk to employees, the environment, and the company’s food products. Many companies are focused on implementing ways to reduce their footprints on the environment and operate in more environmentally responsible ways. General Mills, the sixth largest food company in the world, has publicly communicated several ways in which it is working to “advance sustainability around the world while minimizing the impact” that its products and packaging have on the environment.

Part of the company’s sustainability message includes the following efforts:

  • reduce water and energy use;
  • control air emissions and wastewater discharges from production operations;
  • manage potentially hazardous materials properly;
  • use recycled content and recyclable materials whenever possible;
  • minimize solid and hazardous waste generation;
  • prevent spills or releases; and
  • support and participate in organizations that promote environmental stewardship and encourage awareness of our shared responsibility for people and the planet.

Nestlé has called water its top priority, aiming “to reduce the amount of water used per kilo of food and beverage” produced, as well as taking care that the water it discharges into the environment is clean.2 Sara Lee is focused on “a LEAN/ Continuous Improvement mind set to relentlessly pursue waste elimination,” and has reduced water consumption at one bakery by “eliminating water-cooled compressors and making our sanitation practices more water efficient.

The Problem With Water

The use of water to clean equipment, to carry the cleaning detergents and sanitizer to the surface and then carry the soils or contaminants away from the surface is common in most food processing companies. The problem with this method is that impurities in the water can drastically alter the effectiveness of the detergent or sanitizer; additionally, any microorganisms in the water will affect the food contact surface. Minerals in the water—and cleaning compounds—can leave behind residue, causing film to form on the machines’ surfaces.

Dry ice blast cleaning leaves behind no residue and produces no secondary waste. Unlike cleaning solvents and chemicals that may be hazardous to the environment, dry ice blast cleaning is an environmentally responsible process, making productive use of otherwise unproductive CO2 and reducing the need for water in the cleaning process. It also eliminates the inconvenience and costliness of wastewater treatment and recycling issues. The dry ice blast cleaning process is a dry process and is, therefore, non-conductive.

Unlike steam cleaning or power washing, dry ice blast cleaning won’t cause flash rust or leave behind a wet surface on which bacteria or mold can grow. It is a fast cleaning method that is used by food companies around the world to clean everything from baking ovens and food conveyors to mixing vats and packaging equipment, all without damaging the equipment. The cleaning process can be performed while the equipment is still hot and running, which eliminates prolonged production shutdown times. And dry ice blasting machines such as those offered by Cold Jet of Cincinnati are portable, which means production equipment can be cleaned while it is still in place, eliminating the need to transport the equipment to designated cleaning areas.

Dry ice blast cleaning can help to dramatically reduce equipment downtime, sanitation labor, cleaning prep time, and costs associated with replacing damaged equipment. It also helps to increase worker productivity and safety, both by allocating labor more efficiently and by eliminating employee exposure to harmful chemicals and the potential for injuries related to manual cleaning processes. Product life is also greatly improved when compared to chemical, water, or abrasive cleaning methods. By using dry ice blast cleaning, companies can support sustainability and green initiatives by eliminating dependency on harmful chemicals and water. Using a cleaning process like dry ice blast cleaning can help to create a cleaner and safer production environment while reducing costs and ensuring the safety and quality of food products.

Today, leading food companies, including Kraft, ConAgra, and Hershey, among many others, are using dry ice blasting in their processing and packaging lines to take advantage of this technology’s cost, quality, productivity, and environmental benefits.

Rabkin is the chief marketing officer for Cold Jet. For more information, call (800) 337-9423 or go to www.coldjet.com.

References

  1. General Mills. A champion’s code of conduct. 2008:15. Available at: http://www.generalmills.com/ corporate/commitment/COC_English_GMI_site.pdf. Accessed December 8, 2008.
  2. Nestlé Policy on the Environment. Nestlé Web site. Available at: http://www.nestle.com/ SharedValueCSR/Environment/Introduction/Introduction.htm. Accessed December 8, 1008.
  3. Sara Lee Corporation: Sustainability Report: 2008. Available at: http://www.saralee.com/sustainability_report/2008/Assets/PDF/SaraLee_SR2008_Environment.pdf. Accessed December 8, 2008.

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