Dry Ice Blast Cleaning for the Food Processing Industry

The food industry faces the constant challenge of maintaining cleanliness and hygienic standards. Traditional cleaning processes that rely on water and manual scrubbing can be time consuming and require strenuous labour. The innovative process of dry ice blast cleaning is quickly gaining widespread acceptance as an alternative to conventional cleaning methods because it is capable of rapidly removing stubborn deposits from both processing equipment and the production environment.  

Dry ice

Dry ice is the term used to describe the solid form of carbon dioxide (CO2), a colourless, tasteless and odourless gas found naturally in our atmosphere. Dry ice is extremely cold (-78.5°C/-109°F) and when exposed to warmer temperatures, instantly vaporizes (sublimates) from a solid into a gas. 

How dry ice cleaning works?

Dry ice blast cleaning units are completely mobile, self-contained systems. Small dry ice pellets, about the size of a grain of rice, are fed from the unit's storage tank into a stream of compressed air. The pellets travel along a flexible hose, exiting through a high-velocity blasting nozzle at approximately the speed of sound.   

An operator directs the pressurized dry ice stream from the blasting nozzle at the contaminated surface. The dry ice blasting process is similar to sand, bead or soda blasting, but it is much gentler. Cleaning is the result of the interaction of several different factors:

  • The turbulent stream of freezing dry ice pellets from the blasting nozzle strikes the contaminated surface and rapidly decreases the temperature. The extreme cold causes the surface contamination to become brittle and fracture. 
  • Unlike abrasive sandblasting, dry ice pellets instantly vaporize on impact with the contaminated surface creating an explosive cleaning effect. This dislodges residues and lifts the contaminants away, leaving nothing behind but a clean, dry surface. The removed materials generally become a light, dry residue, easily swept or vacuumed away. 

Blast cleaning optimization

You can achieve optimal dry ice blasting results by adjusting the pellet speed and flow to suit the specific target surface. Factors to consider for the object being cleaned include the material type (ex: stainless steel, plastic) and the thickness and nature of contamination (ex: baked on residues, hardened glue deposits).    

Typical applications in the food industry

The Canadian Food Inspection Agency (CFIA) accepts food grade dry ice for use as a general cleaner. It also meets United States Department of Agriculture (USDA) guidelines. Dry ice blast cleaning finds numerous applications within the food industry including:  

  • production equipment - ex: ovens, bake trays, slicers, food moulds, fryers  
  • packaging equipment - ex: folders, gluers, palletizers, baggers
  • production environment - ex: walls, floors, piping, exhaust fans
  • electrical components - ex: motors, switches, panels, wiring
  • inaccessible or tightly spaced areas - ex: bulbous welds, conveyor components, crevices, dead ends

Benefits of dry ice cleaning

  • Waterless process — dry ice instantly vaporizes during the blast cleaning process, leaving behind no residues. This waterless cleaning procedure is ideal for industries that rely on dry cleaning methods (ex: bakeries) and for other sensitive cleaning applications (ex: electrical equipment).  
  • Non-corrosive — no abrasive cleaning agents are required, thus avoiding damage to equipment surface integrity (ex: pitting, corrosion).  
  • Deep cleaning — pressurized dry ice effectively cleans various nooks and crannies that are difficult to reach using brushes or other traditional cleaning methods.
  • Microorganism removal — dry ice blasting is effective for the removal of Salmonella, E. coli and Listeria from stainless steel, ceramic tile and food grade plastic surfaces.
  • Costs savings — reduced labour and other sanitation associated costs (ex: chemicals, water savings).
  • Clean hot — equipment surfaces are blast cleaned while still warm, which prevents prolonged shutdown times. 
  • On-site cleaning — mobile blast cleaning machinery eliminates the need for target equipment to be moved to designated cleaning areas.
  • Non-hazardous — the dry ice blast cleaning procedure requires no toxic cleaning chemicals, solvents, sanitizers or detergents.

Disadvantages and possible solutions

  • Contaminants removed during blast cleaning may become airborne. Because particles removed during dry ice cleaning are usually relatively large, airborne particles normally land in the immediate area. Surrounding equipment can be covered or re-cleaned and sanitized.
  • Capital investment required for dry ice blast cleaning equipment may be difficult for small and medium   enterprises to absorb. Instead, dry ice blasting rental equipment is usually available or contractor services may be used. 
  • Painted surfaces are sometimes damaged during the blasting procedure. Adjusting the equipment's pellet speed and flow may prevent such damage.

Safety precautions

  • Proper ventilation when working in confined spaces is vital, because high concentrations of CO2 gas may lead to asphyxiation. 
  • Hearing protection is required because of the extreme noise generated during the blasting process.
  • Protective clothing like gloves and face shields help blast cleaning equipment operators stay safe from the freezing temperatures of the blast nozzle and any loose debris that may fly off equipment they clean.

Related Links

For more information, email the CVO/Food Safety Knowledge Centre or call 204-795-8418 in Winnipeg.