Cleaning in a Dry Processing Environment

Goals of dry cleaning
Benefits of dry cleaning
Tools for dry cleaning
Order of dry cleaning
Alternative dry cleaning methods
Related links

The most common sanitation procedure used in the food industry is a wet process that includes pre-rinsing, washing (with chemicals), post-rinsing and sanitizing. However, in facilities where use of water may increase the risk of microbial growth, alternative dry cleaning procedures are needed. Examples of facilities, or areas within facilities, that require dry cleaning procedures are:

grain and cereal processors (ex: milling)
dry blending (ex: spices, cake mixes, etc.)
warehouses
dry storage areas (ex: packaging, dry ingredients, etc.)

Some facilities (ex: bakeries) will require a combination of wet and dry cleaning.

Goals of dry cleaning

Dry cleaning is an effective cleaning method for low moisture food processing environments. Dry cleaning procedures reduce the risk of product contamination and pest infestation while limiting excess moisture in the dry processing environment.

It is important to remember that dry cleaning methods will not remove all traces of product or result in a sanitized surface but they will help reduce the presence of food safety hazards.

Benefits of dry cleaning

The benefits of effective dry cleaning include the production of safe product, improved shelf life, and reduction of off flavour, odour and color. To an extent, it could also prevent equipment deterioration and increase production efficiency.

Tools for dry cleaning

To prevent cross contamination, tools used for dry cleaning should be color-coded and dedicated for cleaning specific equipment, areas of the facility or types of food residue (ex: allergens). Tools used for cleaning food contact surfaces must not be used on floors. Examples of tools used for dry cleaning include:

brushes
brooms
dust pans
scrapers
vacuums
pressurized air
pigging devices (ex: for cleaning inside pipes)

Care must be taken if using pressurized air to clean. This is necessary to avoid more widely dispersing soils or contaminants (especially allergens) and to prevent injuries that may occur due to flying debris. When you blow air on a workstation or piece of equipment, you are simply moving debris from one area to another to make it easier to pick up. A broom or vacuum cleaner is the best cleaning method.

Compressed air may be needed to clean difficult to reach areas. These include corners, nooks, grooves and other unusual designs that can be difficult to clean. Use the lowest possible pressure to do the work – and do not exceed 30psi. Workers must be trained to follow safe work procedures that include wearing personal protective equipment.

Order of dry cleaning

When performing a dry cleaning procedure, work from the top down. Areas requiring compressed air should be blown off first. Then, move on to overhead fixtures such as pipes and lines, allowing dirt to fall to the surfaces below. This residue is cleaned as you work downward. Cleaning is finished with sweeping or even better, vacuuming the floor.

Alternative dry cleaning methods

Other less common dry cleaning methods include:

Inert particle blasting
- Dry ice pellet blasting involves applying high velocity ice pellets to loosen soil. The dry ice vaporizes on contact and the product residue is then easily removed. Specialized equipment is required.
- Sodium Bicarbonate blasting is similar to the method above for dry ice blasting.
Steam sanitizing involves applying high temperature steam to a surface to kill micro-organisms.

As with any cleaning procedure, the above methods must be validated to ensure they are effective and suitable for use in a facility. Always keep records of your dry cleaning activities.